Loop Area Question for Integrated Amp
- By RickRay
- Solid State
- 5 Replies
Take a look at attachment. Blue is input signal wiring. Red is one method of wiring hot speaker leads, yellow is 2nd method of wiring hot speaker leads. For loop area improvement, I'm thinking the yellow wiring method is better. I'm just looking for someone to verify this true. Sorry for the crappy drawing in advance.
Electrolytics pre vent stamping
These are Japanese and 50 years old. The application isn't critical, I'd just like to know they're serviceable (usable) without pulling them.
The XSD Speaker
This is a thread dedicated to the eXtremely Sexy Dipole (XSD) speaker that originated as a cardboard prototype 8 years ago in this thread.
I built it 8 years ago using cheap $5 woofers and cardboard. It sounded so good, I made a note to myself that I must revisit this one day as a proper speaker in wood.
That day has come and I am so glad I returned.
Predicted (black) and measured frequency response (yellow):
Harmonic distortion at 1W:
Impedance as seen by amp (it’s a 4ohm speaker):
You can listen to the sound here with the midrange driver I finally decided to use - PRV 5MR450NDY:
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Passive crossover design (values redacted because this is a commercial design):
You are welcome to build it using active DSP and I will give you all the info needed for the crossover slopes and frequencies (470Hz and 4700Hz). I managed to do this 3 way with only 12 components. Possibly 11 if I replace the big electrolytic/film combo with a single large value film cap. If you want to do a passive crossover, you will have to be on your own. I’ll give hints but please understand that as a commercial product I can’t give that out for free.
Detail of the planar tweeter (GRS PTT2522-4) with custom CNC’d waveguide and PRV 5MR450NDY midrange (those of you with hawkeyes might notice the PRV is labeled 4ohms - it’s actually an 8ohm, mislabeled as 4):
Detail of midrange and tweeter from the front with painted baffle board (paint is Rustoleum Uni“Oil Rubbed Bronze” for those interested):
Here’s an earlier version using a 6FE100 mid. Very nice but the PRV is better:
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You can see that the phase variation of the tweeter and midrange through the 4700Hz crossover range is very smooth as the phase is almost flat. This would indicate a near quasi transient perfect time alignment of the midrange and tweeter. This will give very convincing percussion and snap for things like drums, guitar, piano, stand up bass etc. The woofer however, because it’s a slot loaded design, has some inherent time delay that’s not so easy (impossible) to make transient perfect with a passive crossover and a flat baffle. However, this doesn’t detract from the realism as the bass below 500Hz doesn’t define the timing realism from a listening standpoint. Plus, this is an open baffle design and the sounds come from many reflecting surfaces front and back of the speaker just like a real drum or bass would sound in a live performance.
Here is how the slot loaded woofers are setup. They are arranged cone to magnet but wired so both diaphragms push the air out of the slot on a positive signal. This allows the natural asymmetric suspension non linearities to self cancel. The magnet inside the chamber also reduces the chamber volume and this allows a higher upper bandwidth for the woofers. The chamber depth from front to back dominates this but the volume plays some effect. The slot dimensions are 2.25mm wide x 5.5in tall each. The idea is to have the slot cross sectional area to be about 33% of the cone area (Sd). This will give a good tradeoff in slot loading to enhance the bass efficiency and to not have too much of an overshoot. By keeping the depth of the slot as short as possible, we can keep the upper bandwidth higher. We are able to get this woofer array to play up to 470Hz before a natural band pass fall off occurs. We can use this natural falloff coupled with an electrical low pass filter at the same frequency to get a 4th order steep falloff for using only a 2nd order filter. This reduces woofer mid range leakage above its passband. Also, with opposed drivers, the cone motion vibrations end up self cancelling. So the speaker has very little vibration despite delivering a massive bass punch.
Speaking of punch and slap, this speaker has perhaps one of the best I have heard. At 91.5dB (some mid bass is at 94dB), it does not take much amp power to do this. I can easily reach loud (but clear) 85dB to 90dB SPLs at listening position with only maybe 6Vrms. It’s a very dynamic and powerful big sounding speaker. But at the same time, can play softly while still delivering very nuanced bass. Bass from dipole that is tall like this 4 slot array also has less floor bounce issues and almost no room modes. You can walk around and the bass is very uniform. The woofers I used are GRS 6.5in poly cone rubber surround 8ohm budget drivers. 16 of them will cost you a little over $200. The amount of air that can be moved by 16x 6.5in woofers is not to be underestimated. It is incredible and about a little more than two 15in drivers per side. But the front profile is much more family (wife) friendly 12in wide. The floor footprint is 12in wide x 14in deep. It stands about 45in tall
The bass arrays are built using 5 sheets of stacked 3/4in MDF:
About 8in deep side U wings surround the woofers to extend the bass as if the baffle were closer to 28in wide:
Lining the back wings with felt it acoustic eggcrate foam helps to make the sound cleaner. It’s optional though. Sounds quite good without it.
I should mention that the woofers are wired 4x parallel, then two pairs of those in series, then a pair in parallel at the end. Make sure the opposing ones are wired correctly so that they both squeeze air out when the signal is positive. This results in a 4ohm nominal impedance and a sensitivity of about +12dB on top of whatever the nominal 8ohm rating is after baffle step losses. So for an 85dB driver we get about 91.5dB at 2.83v (that’s 2W into 4ohms). What this means is that the drivers barely move for significant SPL and that leaves a lot of headroom so that the distortion is very low.
For anyone interested in building this speaker as a personal DIY project, PM me with your email and I will get you the dimensioned version of this sketch.
Important the cutout diameter for the GRS 6.5in woofers is 5.59in (142mm). Make it smaller than this and the basket won’t be able to fit inside the chamber.
I’ll give you hints on how to do the passive crossover if you like but I would recommend going the active DSP route with three amps. Make sure you use one capable of 4 ohms for the woofers. It’s an easy to make DSP crossover.
In my opinion, it’s one of the best sounding speakers I have built or heard. The dynamics and visceral impact staggering. It is very realistic and can play any music genre well. It excels at dynamic music like orchestral stuff, complex metal guitar bands, jazz ensembles, classic rock, hip hop, techno, pop, and of course girl and guitar easy stuff. I am really impressed by its abilities and hope you give it a try.
If you like to listen to music with large dynamic peaks, this speaker will not disappoint. Bach’s Toccata and Fugue in D minor has a pipe organ crescendo that is registering here at 98dB at listening position 2.5m away in perfect clarity and the speaker isn’t even breaking a sweat. Nominal volume was around 83dB.
Edit May 14, 2023: I’m offering a XO kit and the CNC waveguides in the GB thread here.
Edit July 17, 2022: Woofer array wiring diagram
I built it 8 years ago using cheap $5 woofers and cardboard. It sounded so good, I made a note to myself that I must revisit this one day as a proper speaker in wood.
That day has come and I am so glad I returned.
Predicted (black) and measured frequency response (yellow):
Harmonic distortion at 1W:
Impedance as seen by amp (it’s a 4ohm speaker):
You can listen to the sound here with the midrange driver I finally decided to use - PRV 5MR450NDY:
Login to view embedded media
Passive crossover design (values redacted because this is a commercial design):
You are welcome to build it using active DSP and I will give you all the info needed for the crossover slopes and frequencies (470Hz and 4700Hz). I managed to do this 3 way with only 12 components. Possibly 11 if I replace the big electrolytic/film combo with a single large value film cap. If you want to do a passive crossover, you will have to be on your own. I’ll give hints but please understand that as a commercial product I can’t give that out for free.
Detail of the planar tweeter (GRS PTT2522-4) with custom CNC’d waveguide and PRV 5MR450NDY midrange (those of you with hawkeyes might notice the PRV is labeled 4ohms - it’s actually an 8ohm, mislabeled as 4):
Detail of midrange and tweeter from the front with painted baffle board (paint is Rustoleum Uni“Oil Rubbed Bronze” for those interested):
Here’s an earlier version using a 6FE100 mid. Very nice but the PRV is better:
Login to view embedded media
You can see that the phase variation of the tweeter and midrange through the 4700Hz crossover range is very smooth as the phase is almost flat. This would indicate a near quasi transient perfect time alignment of the midrange and tweeter. This will give very convincing percussion and snap for things like drums, guitar, piano, stand up bass etc. The woofer however, because it’s a slot loaded design, has some inherent time delay that’s not so easy (impossible) to make transient perfect with a passive crossover and a flat baffle. However, this doesn’t detract from the realism as the bass below 500Hz doesn’t define the timing realism from a listening standpoint. Plus, this is an open baffle design and the sounds come from many reflecting surfaces front and back of the speaker just like a real drum or bass would sound in a live performance.
Here is how the slot loaded woofers are setup. They are arranged cone to magnet but wired so both diaphragms push the air out of the slot on a positive signal. This allows the natural asymmetric suspension non linearities to self cancel. The magnet inside the chamber also reduces the chamber volume and this allows a higher upper bandwidth for the woofers. The chamber depth from front to back dominates this but the volume plays some effect. The slot dimensions are 2.25mm wide x 5.5in tall each. The idea is to have the slot cross sectional area to be about 33% of the cone area (Sd). This will give a good tradeoff in slot loading to enhance the bass efficiency and to not have too much of an overshoot. By keeping the depth of the slot as short as possible, we can keep the upper bandwidth higher. We are able to get this woofer array to play up to 470Hz before a natural band pass fall off occurs. We can use this natural falloff coupled with an electrical low pass filter at the same frequency to get a 4th order steep falloff for using only a 2nd order filter. This reduces woofer mid range leakage above its passband. Also, with opposed drivers, the cone motion vibrations end up self cancelling. So the speaker has very little vibration despite delivering a massive bass punch.
Speaking of punch and slap, this speaker has perhaps one of the best I have heard. At 91.5dB (some mid bass is at 94dB), it does not take much amp power to do this. I can easily reach loud (but clear) 85dB to 90dB SPLs at listening position with only maybe 6Vrms. It’s a very dynamic and powerful big sounding speaker. But at the same time, can play softly while still delivering very nuanced bass. Bass from dipole that is tall like this 4 slot array also has less floor bounce issues and almost no room modes. You can walk around and the bass is very uniform. The woofers I used are GRS 6.5in poly cone rubber surround 8ohm budget drivers. 16 of them will cost you a little over $200. The amount of air that can be moved by 16x 6.5in woofers is not to be underestimated. It is incredible and about a little more than two 15in drivers per side. But the front profile is much more family (wife) friendly 12in wide. The floor footprint is 12in wide x 14in deep. It stands about 45in tall
The bass arrays are built using 5 sheets of stacked 3/4in MDF:
About 8in deep side U wings surround the woofers to extend the bass as if the baffle were closer to 28in wide:
Lining the back wings with felt it acoustic eggcrate foam helps to make the sound cleaner. It’s optional though. Sounds quite good without it.
I should mention that the woofers are wired 4x parallel, then two pairs of those in series, then a pair in parallel at the end. Make sure the opposing ones are wired correctly so that they both squeeze air out when the signal is positive. This results in a 4ohm nominal impedance and a sensitivity of about +12dB on top of whatever the nominal 8ohm rating is after baffle step losses. So for an 85dB driver we get about 91.5dB at 2.83v (that’s 2W into 4ohms). What this means is that the drivers barely move for significant SPL and that leaves a lot of headroom so that the distortion is very low.
For anyone interested in building this speaker as a personal DIY project, PM me with your email and I will get you the dimensioned version of this sketch.
Important the cutout diameter for the GRS 6.5in woofers is 5.59in (142mm). Make it smaller than this and the basket won’t be able to fit inside the chamber.
I’ll give you hints on how to do the passive crossover if you like but I would recommend going the active DSP route with three amps. Make sure you use one capable of 4 ohms for the woofers. It’s an easy to make DSP crossover.
In my opinion, it’s one of the best sounding speakers I have built or heard. The dynamics and visceral impact staggering. It is very realistic and can play any music genre well. It excels at dynamic music like orchestral stuff, complex metal guitar bands, jazz ensembles, classic rock, hip hop, techno, pop, and of course girl and guitar easy stuff. I am really impressed by its abilities and hope you give it a try.
If you like to listen to music with large dynamic peaks, this speaker will not disappoint. Bach’s Toccata and Fugue in D minor has a pipe organ crescendo that is registering here at 98dB at listening position 2.5m away in perfect clarity and the speaker isn’t even breaking a sweat. Nominal volume was around 83dB.
Edit May 14, 2023: I’m offering a XO kit and the CNC waveguides in the GB thread here.
Edit July 17, 2022: Woofer array wiring diagram
Aegis DIY Tube Headphone Amplifier
- By L0rdGwyn
- Tubes / Valves
- 228 Replies
Hello,
I am releasing a DIY tube amplifier project, the first complete DIY project I've released on this forum. The amplifier is called Aegis.
I started my DIY journey on the headphone forum Head-Fi. I have something of a tube DIY blog there where I catalog all of my ongoing projects. For a short period of time, I was building and selling my designs as a hobby business, but quickly realized I didn't have the time for it working a full time job. I thought I'd work on a DIY amplifier that forum members could build for themselves without my involvement. I've been working on it for the past year or so.
This is a headphone enthusiast's tube amplifier. I say that as I'm sure some will balk at the cost of parts, which is roughly $2,000 USD. Given what some people are willing to pay for commercial tube headphone amplifiers, which are creeping toward five figure prices, it's relatively affordable. I tried to come up with a design that 1) is easy to build, even for a novice DIYer, 2) uses easy to acquire vacuum tubes, 3) is simple and robust with low likelihood of parts failure and easy to troubleshoot, 4) uses a circuit that is not readily available on the commercial market, and 5) sounds good! I do not typically build budget-oriented designs for myself, and I did not do so here. I like to build amplifiers that look like professionally made products. Please abstain from telling me that it is too expensive, a waste of money, etc. You do not have to build it.
I've included download links to the BOM, chassis CAD files, and an exhaustive project document that includes an explanation of the circuit, schematics, recommended equipment, information on acquiring parts, step-by-step instructions with photos, testing procedures, and some basic measurements. Please note the instructions are written for a new DIYer, not one with experience, so they are very detailed. The gerber files to order the PCBs are attached to this post.
Measurements are in the last section of the build document.
You can find some subjective impressions of the amplifier here:
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https://www.head-fi.org/threads/aegis-diy-tube-headphone-amplifier.965530/post-17224730
https://www.head-fi.org/threads/zmf-caldera-new-planar-magnetic-from-zmf.964836/post-17553801
Please let me know if you come across any typos or anything seems out of place and I will try to address it.
Link to build document PDF: https://drive.google.com/file/d/1C2NSRh8DkC1Blr2GMVC_83XAdM0IUFZA/view?usp=sharing
Link to the Excel BOM: https://docs.google.com/spreadsheet...ouid=113213015624875847507&rtpof=true&sd=true
Link to zipped chassis CAD files: https://drive.google.com/file/d/1GXCq11-S97FtTey2lVpv6CgkBul4Uryb/view?usp=sharing
I am releasing a DIY tube amplifier project, the first complete DIY project I've released on this forum. The amplifier is called Aegis.
I started my DIY journey on the headphone forum Head-Fi. I have something of a tube DIY blog there where I catalog all of my ongoing projects. For a short period of time, I was building and selling my designs as a hobby business, but quickly realized I didn't have the time for it working a full time job. I thought I'd work on a DIY amplifier that forum members could build for themselves without my involvement. I've been working on it for the past year or so.
This is a headphone enthusiast's tube amplifier. I say that as I'm sure some will balk at the cost of parts, which is roughly $2,000 USD. Given what some people are willing to pay for commercial tube headphone amplifiers, which are creeping toward five figure prices, it's relatively affordable. I tried to come up with a design that 1) is easy to build, even for a novice DIYer, 2) uses easy to acquire vacuum tubes, 3) is simple and robust with low likelihood of parts failure and easy to troubleshoot, 4) uses a circuit that is not readily available on the commercial market, and 5) sounds good! I do not typically build budget-oriented designs for myself, and I did not do so here. I like to build amplifiers that look like professionally made products. Please abstain from telling me that it is too expensive, a waste of money, etc. You do not have to build it.
I've included download links to the BOM, chassis CAD files, and an exhaustive project document that includes an explanation of the circuit, schematics, recommended equipment, information on acquiring parts, step-by-step instructions with photos, testing procedures, and some basic measurements. Please note the instructions are written for a new DIYer, not one with experience, so they are very detailed. The gerber files to order the PCBs are attached to this post.
Measurements are in the last section of the build document.
You can find some subjective impressions of the amplifier here:
Login to view embedded media
https://www.head-fi.org/threads/aegis-diy-tube-headphone-amplifier.965530/post-17224730
https://www.head-fi.org/threads/zmf-caldera-new-planar-magnetic-from-zmf.964836/post-17553801
Please let me know if you come across any typos or anything seems out of place and I will try to address it.
Link to build document PDF: https://drive.google.com/file/d/1C2NSRh8DkC1Blr2GMVC_83XAdM0IUFZA/view?usp=sharing
Link to the Excel BOM: https://docs.google.com/spreadsheet...ouid=113213015624875847507&rtpof=true&sd=true
Link to zipped chassis CAD files: https://drive.google.com/file/d/1GXCq11-S97FtTey2lVpv6CgkBul4Uryb/view?usp=sharing
Constructing Broskie tube i/v
- By gabdx
- Digital Source
- 0 Replies
This is about building this. I did not find any build over the Internet. It looks fairly simple to build all it needs is parts values and parts lists as well as details about the CCS so that it can be built without any fuss.
A little background about me. I have no formation in electronics and no commercial interests. I built Broskie unbalancer with great success as well as the Aikido. I had a designer build me a discrete transistor I/V for tda1541, which sounded very plain. I recently modified a pcm58dac from China.
While the AKM dac is a disappointment in all aspects of its sound, with Broskie schematic and a little bit of diy upgrades it keeps impressing me. Where it lacks is in the texture department and sound signature.
On the pcm58, it is highly scalable and responds very well to filters upgrades as well as modern development regulators in the power supply. 4 bits are adjustable. Good chips also exist in decent quantities. It sounds very similar to newer AKM dacs in it's neutral presentation. Maybe the best dac was Cirrus 4398? we should re-evaluate this!
The Opamp classic i/v filter is very accurate especially with modern opamp such as OPA1611, 604, and gets the maximum out of the PCM58.
This is for curious dyer's who want to go into tube territory as DAC output. Far from being colored and warm, a proper tube output stage is very accurate and I am confident in Broskie schematic.
Micromega DUO DAC D/A Converter - how many Versions on the Market? - Overview wanted
- Digital Line Level
- 3 Replies
Attachments
-
Micromega duo-pro PCB top.jpg -
Micromega duo-pro2 PCB top.webp -
Micromega duo-pro2-PCB.webp -
Micromega duo-pro2-PCB-II.webp -
Micromega duo-pro rear.jpg -
Micromega duo-pro2 rear.webp -
Micromega duo-pro2-bottom.webp -
Micromega duo-pro front.jpg -
Micromega duo-pro2 front.webp -
Micromega DUO DAC+PRE front.jpg -
Micromega DUO DAC+PRE rear.jpg -
Micromega DUO DAC+PRE Toroid-I.jpg -
Micromega DUO DAC+PRE Toroid-V.jpg -
Micromega DUO DAC+PRE-PCB-I.jpg -
Micromega DUO DAC+PRE-PCB-IV.jpg -
Micromega DUO DAC+PRE-PCB-V.jpg
Mark Johnson soft start control board
F/S a built up and working board. Unfortunately health problems mean that I wont be completing the project this was intended for. Asking £65 with UK delivery included.
Mini speaker - Japanese 100 Yen shop "Daiso" - 300 Yen speaker's modified model
- By nandappe
- Full Range
- 116 Replies
This driver has weak bass and treble, but the vocal extension is excellent.
It would be difficult to achieve this kind of vocal reproduction with a multi-way speaker using a network or a filtered full-range speaker.
Internal wiring was supplied with the speakers, 6mm MDF and PVC sheets were made by Daiso.
Material cost is less than 1000 yen (6.5 USD) per pair.
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It would be difficult to achieve this kind of vocal reproduction with a multi-way speaker using a network or a filtered full-range speaker.
Internal wiring was supplied with the speakers, 6mm MDF and PVC sheets were made by Daiso.
Material cost is less than 1000 yen (6.5 USD) per pair.
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Attachments
Zenductor 2 in 2U Modushop Galaxy Chassis
The plan is to use this thread to document my integration of a Zenductor 2 stereo pair into a Modushop Galaxy 1GX388 2U chassis.
Except for removal of the tall Mosfet heatsinks, relocation of the transistors to the chassis sidewalls and reuse of the speaker posts I tried to leave the Zenductor 2s unmodified, and make the assembly as modular as possible. DC power and RCA input connections are via connectorized jumper cables. A preamp mounted to the front panel can be optionally looped into the signal path via rear panel RCA input and output connectors. I integrated two digital bias current displays and a large illuminated push button power switch into the front panel.
Heatsinks and transistors after removal:
They look a bit sad, with their legs cut off. Will they ever run again? ;-)
The amps just fit with the jumper cable connections:
Transistors mounted on sidewalls (1.4 K/W heatsinks, tested in https://www.diyaudio.com/community/...galaxy-1gx388-2u-chassis.426972/#post-7997356):
A quick test to see whether the Mosfets survived:
The 3-digit display shows the bias current. All four transistors survived, and get warm, but not hot. Definitely an improvement over the original heatsinks.
A thermal image:
Lots of filing for the bias display cutouts:
It's been a while since I had to do 'precision filing'; maybe I'll fill the gap later.
Almost finished (except for the preamp connections):
With top cover:
Rear panel, still with empty holes for preamp connections:
Except for removal of the tall Mosfet heatsinks, relocation of the transistors to the chassis sidewalls and reuse of the speaker posts I tried to leave the Zenductor 2s unmodified, and make the assembly as modular as possible. DC power and RCA input connections are via connectorized jumper cables. A preamp mounted to the front panel can be optionally looped into the signal path via rear panel RCA input and output connectors. I integrated two digital bias current displays and a large illuminated push button power switch into the front panel.
Heatsinks and transistors after removal:
They look a bit sad, with their legs cut off. Will they ever run again? ;-)
The amps just fit with the jumper cable connections:
Transistors mounted on sidewalls (1.4 K/W heatsinks, tested in https://www.diyaudio.com/community/...galaxy-1gx388-2u-chassis.426972/#post-7997356):
A quick test to see whether the Mosfets survived:
The 3-digit display shows the bias current. All four transistors survived, and get warm, but not hot. Definitely an improvement over the original heatsinks.
A thermal image:
Lots of filing for the bias display cutouts:
It's been a while since I had to do 'precision filing'; maybe I'll fill the gap later.
Almost finished (except for the preamp connections):
With top cover:
Rear panel, still with empty holes for preamp connections:
Attachments
Can somebody help me make this PCB smaller with KiCad 9 and give an opinion
- By sbelyo
- Software Tools
- 22 Replies
So I've never learned how to layout a PCB. I figured I'd throw $15 at fiverr to see if someone would layout this transformer pcb for me with wire to board terminals exposing the taps and giving mounting holes. Attached is what I got back dimensions are 108 mm x 59.9 mm
I'm wanting to shrink it to say 83 mm x 58 mm I just don't know how.
The transformer is a triad FS16-400-C2
Datasheet: http://catalog.triadmagnetics.com/Asset/FS16-400-C2.pdf
The terminal blocks are Phoenix Contact 1706756
Can someone take a look at the gerbers and give me some pointers on how to do it, and if they would make any improvements?
I'm wanting to shrink it to say 83 mm x 58 mm I just don't know how.
The transformer is a triad FS16-400-C2
Datasheet: http://catalog.triadmagnetics.com/Asset/FS16-400-C2.pdf
The terminal blocks are Phoenix Contact 1706756
Can someone take a look at the gerbers and give me some pointers on how to do it, and if they would make any improvements?
The Lab is Back!
- Pass Labs
- 65 Replies
It took a looooooong time, but I finally moved into my new place. And lookie, there's a lab!
Still a lot to unpack and organize, but fingers crossed for some DIY fun this summer 🙂
Miss y'all
Mike
Still a lot to unpack and organize, but fingers crossed for some DIY fun this summer 🙂
Miss y'all
Mike
The Wolverine 4th Group buy
- By stuartmp
- Group Buys
- 126 Replies
This project is a Group Buy. The public group here must agree - in this thread - on what parts will be sold, by whom, and where. Members must abide by those agreements. Any regular sales of the Group Buy PCB, kits or other specific related items outside of diyAudio or this thread will result in the removal of that person from diyAudio.com This is completely at the discretion of the Moderation Team.No one shall send unsolicited or blind sales PMs to anyone else on the forum. This has long been against the rules and will also result in the immediate banning of any person who does so.
Keep this Group Buy clean and noncommercial or risk immediate removal from diyAudio.com.
Hi Guy's
Please Register your details for the Wolverine 4th group buy - Pre Order
After the success of the 3rd group buy in Xmas 2023 and the increasing demand for boards we would like to announce another group buy for the DiyAudio community.
Thank you all for your support and interest in the Wolverine project over the past 2 years.
Once again we will do things a little differently then the 1st group buy to help save on the amount of processing time involved.
Please read the detailed instructions below on how to register for the 4th group buy.
Color will be determined based on numbers. If we don't have sufficient numbers only a single color will be ordered.
Please specify your preference on your order sheet.
To view further details about the EF3-3 vs the EF3-4 please read this post
The prices for 1 and 2 sets of boards are as follows.
For the EF3-3
2 x Precision EF3-3 boards which includes 2 x wolverine IPS boards. (Color to be determined, Green, Black, Blue)
$50.00 USD.
4 x Precision EF3-3 boards which includes 4 x wolverine IPS boards. (Color to be determined, Green, Black, Blue)
$90.00 USD.
For the EF3-4
2 x Precision EF3-4 boards which includes 2 x wolverine IPS boards. (Color to be determined, Green, Black, Blue)
$55.00 USD.
4 x Precision EF3-4 boards which includes 4 x wolverine IPS boards. (Color to be determined Green, Black, Blue)
$95.00 USD.
If you would like more than 2 sets of either boards or you would like to change your indicated quantity,
please let us know and we will get back to you with further pricing.
Please note: These prices do not include shipping to your location.
Shipping will be done at cost price plus an additional $3.00 for the box and packing material.
No added or extra handling charges will be applied.
A copy of the shipping receipt will be emailed to your personal email address once your shipping has been paid for.
Each order will contain:
- The PCB’s that you ordered.
- An A3 copy of the schematic. Both 57V and 64V rail voltage versions have been created. (Dropbox Link)
- The Build Guide, which is a 32 page illustrated A4 color document. (Dropbox Link)
- BOM in excel, listing all the components and mouser part numbers required to build the Wolverine. (Dropbox Link)
- Hole Pattern DXF file and 1:1 PDF file of the Hole locations for Heatsink drilling. (Dropbox Link)
- How to wire a Audio Amplifier. PDF document by Bonsai showing Audio Amplifier wiring best practices. (Dropbox Link)
- Any future updates to the Build Guide, BOM or Schematic will be updated in Dropbox Link for you to download. So please include the e-mail address you would like to use for this purpose.
We are taking payment through PayPal, and you will be sent a PayPal request to make your payment when the boards are ready to ship.
To Register your details
Please open the attached file and enter your details into the excel order sheet.
Please fill out all the fields and then e-mail it directly back to me so we can enter your details into our database:
My e-mail address is stuartmp@internode.on.net. Please use your DiyAudio username in the subject for example
Subject: Wolverine Project – Your DiyAudio User Name
If you have any trouble opening the attached file, please just reply to this PM and provide the following details.
Please be very specific to save any confusion.
- The total number and type of each EF3-3 & EF3-4 boards you would like.
- Your full name, full postal address including country and post code,
- Please include your Phone number for tracking updates once your boards are shipped.
- Your PayPal e-mail address
- Your personal e-mail address for the Dropbox documentation link to be e-mail to you.
We will keep all forum members up to date on the progress of the group buy.
Once we receive the boards we will pack them up, calculate shipping and then send out the payment request to each forum member.
Then once payment has been made you will receive a tracking number so you can track your orders arrival.
Please don't use my e-mail address for any other purpose as I don't have time to respond.
Please post any questions regarding the build of the Wolverine to the main Wolverine Build thread on the forum.
Please post any questions related to ordering through to me using the DiyAudio PM system.
You personal information will not be used for any other purpose and won't be passed onto anyone else.
Kind Regards
Stuart & the Wolverine project team.
Wolverine development Thread
Wolverine Build Thread
Youtube build series
Please see the attached pdf for pricing details. Just let me know what options you'd like when you order your boards.
Please note. The prices shown include the cost of the boards.
------------------------------------------------------------------------------------------------------------------------------------
Heatsinks
We're are also excited to share some great news, which we hope will enhance your amplifier building experience.
The Wolverine team is thrilled to announce that anodized heat sinks are now available for our project.
These heat sinks are specifically designed to fit perfectly with our current boards. Here's what we've got:
- Heat sinks suitable for the IPS Boards V4.9.
- Pre-driver heat sinks designed for V4.2 of the EF3-3 & EF3-4 Output Stage Boards (OPS Boards).
- Driver heat sinks for V4.2 of the EF3-3 Output Stage Boards.
- EF3-3 IPS, Pre-Driver & Driver: $27.5 USD (6 Heatsinks Total)
- EF3-4 IPS & Pre-Driver: $22.5 USD (4 Heatsinks Total)
@jjs is in the USA, and I am in Australia, so please PM whoever is closer to you, and we'll arrange some for you.
Happy building!
Best regards,
Stuart & the Wolverine Team
Attachments
DIY PC/Desktop Setup
- Electronic Design
- 108 Replies
Hello Community,
i want to build my own audio setup for my desktop PC.
My idea is to have 1 tweeter and 1 midrange woofer on the left and right side,
completing the setup with 1 subwoofer in the center under my PC monitor.
What I am mainly listening to is obviously music, occasional podcasts and movies.
The audiosignal is coming only from the aux output (single ended?) of the PC.
The speakers:
2x Tweeter => https://www.parts-express.com/Dayton-Audio-DC25T-8-1-Titanium-Dome-Tweeter-275-045?quantity=1
2x Mid-range => https://www.parts-express.com/Dayton-Audio-DC160-4-6-1-2-Classic-Woofer-Speaker-295-309?quantity=1
1x Sub => https://www.parts-express.com/Dayton-Audio-SD215A-88-8-DVC-Subwoofer-295-484?quantity=1
The IC's I want to use are the TPA3116 for the tweeter and midrange speakers, the TPA3156 is for the subwoofer.
Configuration of the tweeters 2x15W, midrange 2x50W, subwoofer 1x70W.
Now, my first question is...is this even possible, meaning if this is a reasonable setup, does it make any sense what I am trying to create,
leaving out the fact that there are finished solutions for it?
If this all makes any sense, here is what I managed to do in Kicad 6 until now:
Tweeter schematic:
- I am planning to have a couple of external switches to control the state of the amplifiers,
meaning that I have one switch to mute them all and one switch for the shutdown functionality.
- From what I understand in the datasheet the three IC's need to be synchronized.
I decided to leave it to the 400Khz, for the simple reason because the recommended schematic in the datasheet, already does it this way.
How am I supposed to connect those three IC's together, the datasheet makes the example only with two same IC's. I didn't find any citings stating that there is the possibility of connecting more than two IC's togther, so I guess I won't be able to use a subwoofer in this configuration?
Regarding the master IC, which one should it be? I currently picked the tweeter IC as a master.
- My biggest confusion remains on the plimit voltage divider, which sets the output power limit for the speakers.
This is the formula I found in the datasheet.
For Pout, do I need to take 15W or 30W in the calculation?
Rs is the total series resistance, is this the resistance of the speakers on the output + Rds(on) (120mOhm) + the output filter resistance. What do I do if don't have a filter yet, do I need one?
In theory I have all the values required, except for Vp, so I altered the formula to solve for Vp. I got some results and tried to calculate the voltage divider values with the appropriate formula and came to 13,5KOhm and 10KOhm...obviously I do not feel very confident of the result because of the explained reasons above.
- For the supplyvoltage, can I power it all with 24V?
- When the power output of the amplifier changes, do I need to change any output components too? Like the inductors? Do they remain the same if I want to drive a 15W speaker or 50W speaker?
- The endgoal is to have all the components in THT format, except for the amplifier IC, because I would like to solder it myself. Is this a good idea or should I switch to SMD? Does it change anything on the functionality/quality of the endproduct?
These are the questions for now, I also made the schematic for the midrange and subwoofer, but the questions are the same, just for another usecase. So I am going to leave it out for now.
I am also waiting with the pcb design, since I am not so sure what I started here in the schematic...
With the hope that I have chosen the right section of the forum, I would like to thank in advance those who are willing to go through this project with me.
i want to build my own audio setup for my desktop PC.
My idea is to have 1 tweeter and 1 midrange woofer on the left and right side,
completing the setup with 1 subwoofer in the center under my PC monitor.
What I am mainly listening to is obviously music, occasional podcasts and movies.
The audiosignal is coming only from the aux output (single ended?) of the PC.
The speakers:
2x Tweeter => https://www.parts-express.com/Dayton-Audio-DC25T-8-1-Titanium-Dome-Tweeter-275-045?quantity=1
2x Mid-range => https://www.parts-express.com/Dayton-Audio-DC160-4-6-1-2-Classic-Woofer-Speaker-295-309?quantity=1
1x Sub => https://www.parts-express.com/Dayton-Audio-SD215A-88-8-DVC-Subwoofer-295-484?quantity=1
The IC's I want to use are the TPA3116 for the tweeter and midrange speakers, the TPA3156 is for the subwoofer.
Configuration of the tweeters 2x15W, midrange 2x50W, subwoofer 1x70W.
Now, my first question is...is this even possible, meaning if this is a reasonable setup, does it make any sense what I am trying to create,
leaving out the fact that there are finished solutions for it?
If this all makes any sense, here is what I managed to do in Kicad 6 until now:
Tweeter schematic:
- I am planning to have a couple of external switches to control the state of the amplifiers,
meaning that I have one switch to mute them all and one switch for the shutdown functionality.
- From what I understand in the datasheet the three IC's need to be synchronized.
I decided to leave it to the 400Khz, for the simple reason because the recommended schematic in the datasheet, already does it this way.
How am I supposed to connect those three IC's together, the datasheet makes the example only with two same IC's. I didn't find any citings stating that there is the possibility of connecting more than two IC's togther, so I guess I won't be able to use a subwoofer in this configuration?
Regarding the master IC, which one should it be? I currently picked the tweeter IC as a master.
- My biggest confusion remains on the plimit voltage divider, which sets the output power limit for the speakers.
This is the formula I found in the datasheet.
For Pout, do I need to take 15W or 30W in the calculation?
Rs is the total series resistance, is this the resistance of the speakers on the output + Rds(on) (120mOhm) + the output filter resistance. What do I do if don't have a filter yet, do I need one?
In theory I have all the values required, except for Vp, so I altered the formula to solve for Vp. I got some results and tried to calculate the voltage divider values with the appropriate formula and came to 13,5KOhm and 10KOhm...obviously I do not feel very confident of the result because of the explained reasons above.
- For the supplyvoltage, can I power it all with 24V?
- When the power output of the amplifier changes, do I need to change any output components too? Like the inductors? Do they remain the same if I want to drive a 15W speaker or 50W speaker?
- The endgoal is to have all the components in THT format, except for the amplifier IC, because I would like to solder it myself. Is this a good idea or should I switch to SMD? Does it change anything on the functionality/quality of the endproduct?
These are the questions for now, I also made the schematic for the midrange and subwoofer, but the questions are the same, just for another usecase. So I am going to leave it out for now.
I am also waiting with the pcb design, since I am not so sure what I started here in the schematic...
With the hope that I have chosen the right section of the forum, I would like to thank in advance those who are willing to go through this project with me.
Sell THF-51s 2SK182ES NEW NOS TO-79 SIT V-FET, from Japan TOKIN
- By pras1170
- Vendor's Bazaar
- 338 Replies
Tokin SissySIT THF-51S 2SK182ES MJ21193G MJ21194G MJ21194 LM350K STEEP+ 2N5566 My quotation does not include the handling fee of PAYPAL. Please understand that my quotation does not include the handling fee of paying PAYPAL. Old second-hand 2SK180 K180 appearance
2SB206 B206 2SB205 B205 TO-79 NOS New 2SB206 GE-PNP 80 V 30 A 80 W Quantity: 50PCS 1 piece USD: 65.28
THF-51S 2SK182ES K182ES THF51S SissySIT Friends who need matching. Please leave a message.
The event is only open to BBS friends because each VGS may be different, so for friends who need more, I need to spend a few days testing (need to measure a lot) (because everyone trusts me, so I do it myself. I may spend A few days, because I have other work to do, so I will try to measure the time if I can match them randomly, the amount will be slightly higher if you need to follow VGS -4V or more, hope you all can understand, thank you)
EMAIL :378632242@qq.com SKYPE: Live broadcast: 378632242
2:2SK182ES K182ES NOS NEW v-fet TOKIN from Japan Spot quantity: 50PCS
Matching price: USD: 100/1PCS Thf-51s 2SK182ES features: each has a different sequence number, a different number, a 1-10 number (this is a brand new original, only owned by NOS)
Mica thickness 4.5 (thickest)
Buy thf-51s 2SK182ES for free insulating pads, mica sheets, screws
It can be delivered in a package
(if you do not have a friend who bought thf-51s, you need to pay the postage by yourself. If you need, you can leave a message or send it to my email:378632242@qq.com.)
See the picture:
MJ21193G MJ21194G MJ21194 MJ21193 NOS NEW ON Motorola
1pair=USD:11.56
QTY:80pair
NOS NEW ON MJ21193G MJ21194G MJ21193 MJ21194 250V-16A-200W-4MHZ
LM350K LM350K STEEL
USD:11.57 /1PCS
NEW NOS LM350K LM350K STEEP+ 9712+ I have 50PCS
NSC 8608+ LM350K STEEP+ I have 620PCS
LM350K STEEL NEW NOS NSC TO-3 NEW STEELP+ 0142+ NOS 1PCS USD:11.57 I have 785PCS
Brand NSC
Model LM350k
MAX input voltage 35V
The input voltage of MINIi is 4.2V
Adjust the voltage 1.2-33v direct current
Current 3 a MAX
To encapsulate the to - 3
With the original packaging, packaging foam board is die-cast with the manufacturer's brand. I take it apart. I take it apart. Here is a picture of the tube wafer taken by someone using an electron microscope. It can be seen that the wafer is made in Britain. He who knows is sure to know the goods.
The national semiconductor company makes LM350k. It's not a big problem to play with equipment. The money you really spend is worth it. It is also clear that the foam packaging of this tube is also special and each is individually attached to the tube, rather than the usual one with a cylinder in the middle to separate the surrounding tube. It can directly replace the LM317. This tube can be regarded as the more powerful LM317. The current is twice that of 317, reaching 3A. It is a good choice to supply the machine with sufficient current. Naim power supply board made of high current pipe with low internal resistance, which is a feature pursued by burning friend. Spread knowledge by the way. The quality of the steel tube on the net varies greatly, there are used polish to fill the new, some of the pin resin seal holes are large holes. This kind of imported tubes are all small holes. The color of resin is mainly black, brown, green and red, with few blue. The printed word on the surface of the normal pipe is in the middle, and the position is basically the same. Word is not raised, a bit of brown black, and the surface coating is matte color, won't be very bright, that is polished. Iron tube screw fixation will leave a mark on the screw hole where can distinguish between used and new. This tube is typically quoted at more than 300, which is more expensive than LT's 317.
Refer to the official PDF map for details. You can download the PDF for reference.
Shipping and ordering T&C
Sort:
Please give me a PM with the following information:
Forum ID:
Real name:
The recipient:
Contact number:
Mailing address:
Paypal account email:
Bill of materials, quantity and options
The value of the parcel declared for customs/insurance purposes.
payment:
Exclusively provided by PayPal. PayPal fees are always included in the displayed price.
Prices are shown in US dollars, please specify when placing an order.
Shipping and handling:
Shipping fee and courier method: China Post 12day-20day
After receiving PayPal, I will ship within 2 business days.
If someone has not received your package within 20 business days of my delivery notice, please let me know.
The shipping and packaging charges for the order are: 1PCS-4PCS=USD: 12.0 In some countries, China post freight only needs USD: 10.0 (Some countries have far-fetched fare, shipping rates may be high+: USD: 2.0)
4PCS-8PCS=USD: 15.0 (some countries are far away, shipping costs may be high+ USD: 2.0)
Buyers in mainland China, Hong Kong and Taiwan can support the payment (support SF Express)
DHL：If the buyer is in a hurry and wants to receive the goods soon, you can choose DHL.
Shipping fee is: 1PCS-4PCS=USD: 29.22
5PCS-10PCS=USD: 43.84
Because the contract with DHL Express, so the freight, gave me the advantage of the price, the freight will be cheaper
The time limit is: 4-5 days to receive
运输政策：请注意，包裹保险不包含在运输条款和条件中指定的运输费用中。请联系我获取保险报价。如果您想为包裹购买保险，请考虑使用更可靠的递送服务提供商，例如 DHL、EMS 或 FEDEX。 PM，给我留言，如果接受条件，请只下订单。谢谢您的理解。
2SK182ES thf-51s 需要一个匹配的朋友
请留言
Pairing就是配对的价格（PM就可以了）
当我不忙的时候，我会测量。下面是2SK182ES的流程。
2SB206 B206 2SB205 B205 TO-79 NOS New 2SB206 GE-PNP 80 V 30 A 80 W Quantity: 50PCS 1 piece USD: 65.28
THF-51S 2SK182ES K182ES THF51S SissySIT Friends who need matching. Please leave a message.
The event is only open to BBS friends because each VGS may be different, so for friends who need more, I need to spend a few days testing (need to measure a lot) (because everyone trusts me, so I do it myself. I may spend A few days, because I have other work to do, so I will try to measure the time if I can match them randomly, the amount will be slightly higher if you need to follow VGS -4V or more, hope you all can understand, thank you)
EMAIL :378632242@qq.com SKYPE: Live broadcast: 378632242
2:2SK182ES K182ES NOS NEW v-fet TOKIN from Japan Spot quantity: 50PCS
Matching price: USD: 100/1PCS Thf-51s 2SK182ES features: each has a different sequence number, a different number, a 1-10 number (this is a brand new original, only owned by NOS)
Mica thickness 4.5 (thickest)
Buy thf-51s 2SK182ES for free insulating pads, mica sheets, screws
It can be delivered in a package
(if you do not have a friend who bought thf-51s, you need to pay the postage by yourself. If you need, you can leave a message or send it to my email:378632242@qq.com.)
See the picture:
MJ21193G MJ21194G MJ21194 MJ21193 NOS NEW ON Motorola
1pair=USD:11.56
QTY:80pair
NOS NEW ON MJ21193G MJ21194G MJ21193 MJ21194 250V-16A-200W-4MHZ
LM350K LM350K STEEL
USD:11.57 /1PCS
NEW NOS LM350K LM350K STEEP+ 9712+ I have 50PCS
NSC 8608+ LM350K STEEP+ I have 620PCS
LM350K STEEL NEW NOS NSC TO-3 NEW STEELP+ 0142+ NOS 1PCS USD:11.57 I have 785PCS
Brand NSC
Model LM350k
MAX input voltage 35V
The input voltage of MINIi is 4.2V
Adjust the voltage 1.2-33v direct current
Current 3 a MAX
To encapsulate the to - 3
With the original packaging, packaging foam board is die-cast with the manufacturer's brand. I take it apart. I take it apart. Here is a picture of the tube wafer taken by someone using an electron microscope. It can be seen that the wafer is made in Britain. He who knows is sure to know the goods.
The national semiconductor company makes LM350k. It's not a big problem to play with equipment. The money you really spend is worth it. It is also clear that the foam packaging of this tube is also special and each is individually attached to the tube, rather than the usual one with a cylinder in the middle to separate the surrounding tube. It can directly replace the LM317. This tube can be regarded as the more powerful LM317. The current is twice that of 317, reaching 3A. It is a good choice to supply the machine with sufficient current. Naim power supply board made of high current pipe with low internal resistance, which is a feature pursued by burning friend. Spread knowledge by the way. The quality of the steel tube on the net varies greatly, there are used polish to fill the new, some of the pin resin seal holes are large holes. This kind of imported tubes are all small holes. The color of resin is mainly black, brown, green and red, with few blue. The printed word on the surface of the normal pipe is in the middle, and the position is basically the same. Word is not raised, a bit of brown black, and the surface coating is matte color, won't be very bright, that is polished. Iron tube screw fixation will leave a mark on the screw hole where can distinguish between used and new. This tube is typically quoted at more than 300, which is more expensive than LT's 317.
Refer to the official PDF map for details. You can download the PDF for reference.
Shipping and ordering T&C
Sort:
Please give me a PM with the following information:
Forum ID:
Real name:
The recipient:
Contact number:
Mailing address:
Paypal account email:
Bill of materials, quantity and options
The value of the parcel declared for customs/insurance purposes.
payment:
Exclusively provided by PayPal. PayPal fees are always included in the displayed price.
Prices are shown in US dollars, please specify when placing an order.
Shipping and handling:
Shipping fee and courier method: China Post 12day-20day
After receiving PayPal, I will ship within 2 business days.
If someone has not received your package within 20 business days of my delivery notice, please let me know.
The shipping and packaging charges for the order are: 1PCS-4PCS=USD: 12.0 In some countries, China post freight only needs USD: 10.0 (Some countries have far-fetched fare, shipping rates may be high+: USD: 2.0)
4PCS-8PCS=USD: 15.0 (some countries are far away, shipping costs may be high+ USD: 2.0)
Buyers in mainland China, Hong Kong and Taiwan can support the payment (support SF Express)
DHL：If the buyer is in a hurry and wants to receive the goods soon, you can choose DHL.
Shipping fee is: 1PCS-4PCS=USD: 29.22
5PCS-10PCS=USD: 43.84
Because the contract with DHL Express, so the freight, gave me the advantage of the price, the freight will be cheaper
The time limit is: 4-5 days to receive
运输政策：请注意，包裹保险不包含在运输条款和条件中指定的运输费用中。请联系我获取保险报价。如果您想为包裹购买保险，请考虑使用更可靠的递送服务提供商，例如 DHL、EMS 或 FEDEX。 PM，给我留言，如果接受条件，请只下订单。谢谢您的理解。
2SK182ES thf-51s 需要一个匹配的朋友
请留言
Pairing就是配对的价格（PM就可以了）
当我不忙的时候，我会测量。下面是2SK182ES的流程。
Zenductor 2 Amp Camp '24 version
A visual guide to the Rothacher/Pass Zenductor 2
The Zenductor 2 is a mono block, single-ended, zero-feedback, Class-A audio amplifier. You need two for stereo.
Nelson’s article can be found here - https://www.diyaudio.com/community/threads/burning-amp-2024.414636/post-7820909
All photos in this guide will show one amplifier being built.
Parts for one amplifier.
Let's look a little closer at al the various bits -
The circuit board everything attaches to.
Zenductor 2 is powered by a 16v 4.5A brick-style Power Supply.
Here's the magic... the big device is the choke (inductor) that loads the output stage. The darling little transformer is used for voltage gain.
Please note the little circular notch in the plastic closest to the camera, this denotes pin 1.
L to R, RCA input jack, DC power connector, power switch
Capacitors. there are 2 different values that look quite similar. The physically bigger can is 4700uF 25V, the smaller is 6800uF 10V. Make sure you have the right one when stuffing the PCB.
Electrolytic capacitors are polarized. It matters which way they are installed. The long lead is positive (+). The can has negative (-) marked on the heatshrink.
This photo show the 4700uF 25v
1000uF 25v
10uF 35v SILMIC input capacitor.
This is a small value poly capacitor used in the notch network, it's not polarized and can be inserted any way.
Speaker jacks.
Nifty rectangular LED
The input section uses an array of 8 matched Jfet.
Output section is comprised of these two matched Mosfet.
Mosfet heatsinks.
M3 hardware for heatsinks.
Assembly will look like this.
The Zenductor 2 is a mono block, single-ended, zero-feedback, Class-A audio amplifier. You need two for stereo.
Nelson’s article can be found here - https://www.diyaudio.com/community/threads/burning-amp-2024.414636/post-7820909
All photos in this guide will show one amplifier being built.
Parts for one amplifier.
Let's look a little closer at al the various bits -
The circuit board everything attaches to.
Zenductor 2 is powered by a 16v 4.5A brick-style Power Supply.
Here's the magic... the big device is the choke (inductor) that loads the output stage. The darling little transformer is used for voltage gain.
Please note the little circular notch in the plastic closest to the camera, this denotes pin 1.
L to R, RCA input jack, DC power connector, power switch
Capacitors. there are 2 different values that look quite similar. The physically bigger can is 4700uF 25V, the smaller is 6800uF 10V. Make sure you have the right one when stuffing the PCB.
Electrolytic capacitors are polarized. It matters which way they are installed. The long lead is positive (+). The can has negative (-) marked on the heatshrink.
This photo show the 4700uF 25v
1000uF 25v
10uF 35v SILMIC input capacitor.
This is a small value poly capacitor used in the notch network, it's not polarized and can be inserted any way.
Speaker jacks.
Nifty rectangular LED
The input section uses an array of 8 matched Jfet.
Output section is comprised of these two matched Mosfet.
Mosfet heatsinks.
M3 hardware for heatsinks.
Assembly will look like this.
Getting the bugs out of a Kenwood KT-900 tuner (RF nerds wanted)
- By sgrossklass
- Analogue Source
- 6 Replies
I recently acquired a Kenwood KT-900 analog tuner. This relatively rare model was second in line behind the KT-1000 in 1981. I'd been interested in these even back in my tuner nerd days in the mid-2000s, but had to "make do" with a KT-80 and KT-1100 instead (as well as a number of other non-Kenwood PLL synthesizers). Now I finally bought one and have developed kind of a love-hate relationship with it. It's an attractive-looking tuner that's a pleasure to operate (and works fine again after cleaning the varicap wiper contacts and readjusting the MPX VCO and REC CAL oscillator, both of which were way out, plus the usual tweak of the LO trimmer), but it's also a bit of a mess. You may know the type.
For starters, the schematic is blooper city, and even the actual unit has inherited some bugs, indicating that it may have been a bit of a rush job:
Left and right channels swap places midway through. (Outputs on the actual unit are correct, but I have yet to check which parts go on which channel.)
Frontend power supply choke L2 is being shorted out by the layout but still populated. 🤦♂️ False alarm, looks like you can just barely make out a gap below one of the drawn inductor coils if you look really closely.
Filter switching diodes for WIDE mode are operated at 4.8/10 mA instead of the 3-4 mA they'd normally be using. R9 value should be higher than it is.
There is an extra 100k resistor in series with the 47k feeding the AFC varicap diode for no apparent reason. Maybe they intended to add some extra capacitance but dropped it? (And while the touch sensing duly disables it when tuning, the AFC still strikes me as rather faster than it needs to be, leading to audible low-level LO modulation, same as the KT-80. It can correct nearly 100 kHz in 1-2 seconds.)
B+ routing shown is incomplete. Frontend and IF strip are being supplied via diode D5 in series (not in schematic), dropping their supply from about 13.5 to 12.8 V. (It goes without saying that the regulator suffers from the same load / mains voltage dependency as the KT-80, varying by about 80 mV, and would appreciate the same kind of feedforward mod that I recently developed and deployed in mine, bringing idle/load delta down from 92 mV to 1-2 mV the other way. The KT-1000 and KT-1100 would have this issue as well, it's just less obvious because they don't have a bunch of LED blinkenlights that can turn on and off.)
Not really a bug, but the unbiased 2.2µ/50V output series caps could probably use some reforming after over 4 decades. I tried it with the diode test of my multimeter, but that seems to have worked temporarily at best, 2.7 V for a few minutes is just not enough I guess. The unit has a nominal -18 V rail, maybe I'll temporarily borrow that.
Oh, and electrolytic capacitor C93 was installed touching dropper resistor R181 (100°C in operation), great job assembly person.
Furthermore, the case construction kinda stinks - tight tolerances and thin sheet metal with little overlap, what could possibly go wrong? (Reassembling it without tuning dragging anywhere is a bit of a challenge.) The paint seems thin and not very robust as well. I liked the KT-80 a whole lot better in that regard, as well as general parts quality. I also tried to find the grub screw for the tuning knob shown in the explosive diagram, looks like the hole goes all the way down to the shaft. Great, an interference fit.
What irks me the most right now is that while sensitivity, selectivity and noise level are good, it generates fairly strong intermod in the frontend with just two pieces of wire on the 300 ohm terminals in my urban environment, while the KT-80 with a very similar frontend - hardly a true miracle of strong-signal handling to begin with - is substantially less impressed under the same conditions. And I'm not even talking cable levels! (Which I can no longer test as analog FM was turned off on there a while back.) I would like to fix that long-term, so here's where I could use some help.
Here are the factors that I think may be contributing to the problem:
Strike 1 - B+. Where the KT-80 supplies its frontend with 14.9ish V stock and 14.3ish V after my mod, the KT-900's only gets 12.8ish V to begin with. That can't be helping. Not entirely sure why they put the frontend and IF strip behind a diode (if it's needed to avoid reverse discharging, I'll be considering putting in a Schottky instead), and why regulated voltage is only 13.5 V to begin with. (I suppose it's closer to 14 V than 14.9 was, so you could argue that some progress has been made.)
Strike 2 - devilish details.
KT-80 frontend (click to enlarge):
KT-900 frontend:
A lot of things are the same - semiconductors (although an LO buffer is added for frequency counter operation), FM gangs (the varicap just adds the AM plates that had been left out on the KT-80), Balou the balun (L19-0026-05), resistor values. Coupling caps are a bit different, but who needs a 100p in front of the RF preamp in this frequency range anyway. LC fixed capacitors are bigger in the RF circuits and smaller in the LO, but since actual variable capacitance has to be pretty much the same and so is the range to be tuned, inductances can't be much different and so Q shouldn't be either. (I'll have to compare frontend pictures.)
One thing struck me as peculiar: The KT-80 gets a 1.5p coupling capacitor for the LO, while it's only 0.5p in the KT-900. Now I am not an RF guru, but that has to be negatively affecting LO levels at the mixer, which in turn would be worsening its strong-signal handling capabilities as it always does. My hunch is that the LO buffer Q2 via its 1.5p may have been posed enough of a load that it kept the LO from operating reliably without easing up elsewhere. Also, why does R7 have to be as low as 1.5k? Something smells of "let's bodge it until it works" here.
Great, now how does one fix that? Do you reckon one could take some hints from the KT-50, a basic little tuner with a frequency counter that used to sit under the KT-80 in Kenwood's lineup around 1980? It uses the same SC114 hybrid but only runs on 8 V, which I guess is what necessitated a bigger value for C7 (one could certainly add a pF or two to the KT-900's 8p as well):
C8 = 1p certainly sounds more promising. Also note R3 = 100k while using the same type for Q2.
Before receiving the unit, I had thought about trying to squeeze in another filter in the wide path, maybe an MA8 or selected MA5 in place of R8 or something, a type with about as much insertion less as needed to get effective terminating impedance (VR1 -> D3 + R14||R15) to about 330 ohms while matching total NARROW insertion loss of an estimated 9 dB:
Diode bias could be fixed while you're in there.
However, selectivity with the two MLs (280 kHz midrange GDT) in WIDE in this European model is actually quite decent, and I don't have to use NARROW with its two additional MJs (150 kHz regular) all that often.
One MA8 would add about 8/5 MLs worth of group delay deviation while being somewhat more selective than one. Mind you, the result would still be more chill than what the KT-80 shipped with for its compromise bandwidth (1x MM (230 kHz GDT) + 2x MS3G (180 kHz selected) of potentially dubious matching). One could also replace the whole shebang with one MP3 (250 kHz GDT) while losing the gain adjustment, but good luck finding GDT filters in this day and age... I think they were discontinued in about 2008.
For starters, the schematic is blooper city, and even the actual unit has inherited some bugs, indicating that it may have been a bit of a rush job:
Left and right channels swap places midway through. (Outputs on the actual unit are correct, but I have yet to check which parts go on which channel.)
Filter switching diodes for WIDE mode are operated at 4.8/10 mA instead of the 3-4 mA they'd normally be using. R9 value should be higher than it is.
There is an extra 100k resistor in series with the 47k feeding the AFC varicap diode for no apparent reason. Maybe they intended to add some extra capacitance but dropped it? (And while the touch sensing duly disables it when tuning, the AFC still strikes me as rather faster than it needs to be, leading to audible low-level LO modulation, same as the KT-80. It can correct nearly 100 kHz in 1-2 seconds.)
B+ routing shown is incomplete. Frontend and IF strip are being supplied via diode D5 in series (not in schematic), dropping their supply from about 13.5 to 12.8 V. (It goes without saying that the regulator suffers from the same load / mains voltage dependency as the KT-80, varying by about 80 mV, and would appreciate the same kind of feedforward mod that I recently developed and deployed in mine, bringing idle/load delta down from 92 mV to 1-2 mV the other way. The KT-1000 and KT-1100 would have this issue as well, it's just less obvious because they don't have a bunch of LED blinkenlights that can turn on and off.)
Not really a bug, but the unbiased 2.2µ/50V output series caps could probably use some reforming after over 4 decades. I tried it with the diode test of my multimeter, but that seems to have worked temporarily at best, 2.7 V for a few minutes is just not enough I guess. The unit has a nominal -18 V rail, maybe I'll temporarily borrow that.
Oh, and electrolytic capacitor C93 was installed touching dropper resistor R181 (100°C in operation), great job assembly person.
Furthermore, the case construction kinda stinks - tight tolerances and thin sheet metal with little overlap, what could possibly go wrong? (Reassembling it without tuning dragging anywhere is a bit of a challenge.) The paint seems thin and not very robust as well. I liked the KT-80 a whole lot better in that regard, as well as general parts quality. I also tried to find the grub screw for the tuning knob shown in the explosive diagram, looks like the hole goes all the way down to the shaft. Great, an interference fit.
What irks me the most right now is that while sensitivity, selectivity and noise level are good, it generates fairly strong intermod in the frontend with just two pieces of wire on the 300 ohm terminals in my urban environment, while the KT-80 with a very similar frontend - hardly a true miracle of strong-signal handling to begin with - is substantially less impressed under the same conditions. And I'm not even talking cable levels! (Which I can no longer test as analog FM was turned off on there a while back.) I would like to fix that long-term, so here's where I could use some help.
Here are the factors that I think may be contributing to the problem:
Strike 1 - B+. Where the KT-80 supplies its frontend with 14.9ish V stock and 14.3ish V after my mod, the KT-900's only gets 12.8ish V to begin with. That can't be helping. Not entirely sure why they put the frontend and IF strip behind a diode (if it's needed to avoid reverse discharging, I'll be considering putting in a Schottky instead), and why regulated voltage is only 13.5 V to begin with. (I suppose it's closer to 14 V than 14.9 was, so you could argue that some progress has been made.)
Strike 2 - devilish details.
KT-80 frontend (click to enlarge):
KT-900 frontend:
A lot of things are the same - semiconductors (although an LO buffer is added for frequency counter operation), FM gangs (the varicap just adds the AM plates that had been left out on the KT-80), Balou the balun (L19-0026-05), resistor values. Coupling caps are a bit different, but who needs a 100p in front of the RF preamp in this frequency range anyway. LC fixed capacitors are bigger in the RF circuits and smaller in the LO, but since actual variable capacitance has to be pretty much the same and so is the range to be tuned, inductances can't be much different and so Q shouldn't be either. (I'll have to compare frontend pictures.)
One thing struck me as peculiar: The KT-80 gets a 1.5p coupling capacitor for the LO, while it's only 0.5p in the KT-900. Now I am not an RF guru, but that has to be negatively affecting LO levels at the mixer, which in turn would be worsening its strong-signal handling capabilities as it always does. My hunch is that the LO buffer Q2 via its 1.5p may have been posed enough of a load that it kept the LO from operating reliably without easing up elsewhere. Also, why does R7 have to be as low as 1.5k? Something smells of "let's bodge it until it works" here.
Great, now how does one fix that? Do you reckon one could take some hints from the KT-50, a basic little tuner with a frequency counter that used to sit under the KT-80 in Kenwood's lineup around 1980? It uses the same SC114 hybrid but only runs on 8 V, which I guess is what necessitated a bigger value for C7 (one could certainly add a pF or two to the KT-900's 8p as well):
C8 = 1p certainly sounds more promising. Also note R3 = 100k while using the same type for Q2.
Before receiving the unit, I had thought about trying to squeeze in another filter in the wide path, maybe an MA8 or selected MA5 in place of R8 or something, a type with about as much insertion less as needed to get effective terminating impedance (VR1 -> D3 + R14||R15) to about 330 ohms while matching total NARROW insertion loss of an estimated 9 dB:
Diode bias could be fixed while you're in there.
However, selectivity with the two MLs (280 kHz midrange GDT) in WIDE in this European model is actually quite decent, and I don't have to use NARROW with its two additional MJs (150 kHz regular) all that often.
One MA8 would add about 8/5 MLs worth of group delay deviation while being somewhat more selective than one. Mind you, the result would still be more chill than what the KT-80 shipped with for its compromise bandwidth (1x MM (230 kHz GDT) + 2x MS3G (180 kHz selected) of potentially dubious matching). One could also replace the whole shebang with one MP3 (250 kHz GDT) while losing the gain adjustment, but good luck finding GDT filters in this day and age... I think they were discontinued in about 2008.
annulation on waveguide
Hello,
I got my hands on a line array waveguide with faital compression: the Wg141 and the Hf146R.
I measured the frequency response, and I had a question about it:
You can see a cancellation at 700 and 1400Hz.
What is it due to, a reflection at the mouth and therefore an internal resonance? ( if we consider c/2L it could match )
Faital lists this waveguide as being usable from 800Hz upwards, so does that mean they don't consider this problem to be a problem for use where it's in the frequency band?
Thanks
I got my hands on a line array waveguide with faital compression: the Wg141 and the Hf146R.
I measured the frequency response, and I had a question about it:
You can see a cancellation at 700 and 1400Hz.
What is it due to, a reflection at the mouth and therefore an internal resonance? ( if we consider c/2L it could match )
Faital lists this waveguide as being usable from 800Hz upwards, so does that mean they don't consider this problem to be a problem for use where it's in the frequency band?
Thanks
Design steps of building a low-jitter master clock
- By zarandok
- Digital Line Level
- 19 Replies
Attachments
New loadline calculator
- By mjmvisser
- Tubes / Valves
- 7 Replies
Hi folks,
I used to use Giuseppe Amato's loadline calculator quite a bit, but grew frustrated with some of its limitations (and annoyed at the ads and other clutter). So, I created my own. It's open source and hosted on github.com, so in theory should never disappear. If I'm no longer able to maintain it, someone else can fork the project and carry on.
You can access it here: https://mjmvisser.github.io/tubestudio/
Source is here: https://github.com/mjmvisser/tubestudio/
Some notable differences:
Here's what it looks like:
Hope you find this useful!
cheers,
-Mark
I used to use Giuseppe Amato's loadline calculator quite a bit, but grew frustrated with some of its limitations (and annoyed at the ads and other clutter). So, I created my own. It's open source and hosted on github.com, so in theory should never disappear. If I'm no longer able to maintain it, someone else can fork the project and carry on.
You can access it here: https://mjmvisser.github.io/tubestudio/
Source is here: https://github.com/mjmvisser/tubestudio/
Some notable differences:
- multiple SPICE models are supported for each tube, and the source for each is linked
- supported mathematical models are:
- Koren triode
- Koren pentode
- Ayumi triode
- Ayumi pentode
- Paintkit triode
- Paintkip pentode
- Robert Weaver's pentode model
- CurveCaptor's extensions to the Rydel and Koren models
- Adrian Immler's triode model
- link to a datasheet is included for each tube
- both fixed and cathode bias are supported
- you can edit the grid bias voltage directly, and all linked parameters update
- output is graphed according to peak input headroom
- max and average output power and effective mu are calculated for you
- all parameters are saved in the URL, so you can bookmark or link directly to a parameterized model
- 12AX7
- 7025
- 6L6GC
- 6L6
- EF80
- 6P25B
- 6V6
- 6N16B
- 6N17B
- 6N21B
- 6P30B
- 6P37N-V
Here's what it looks like:
Hope you find this useful!
cheers,
-Mark
Rescuing & Reimagining a Technics SL-100c
- By mcrushing
- Analogue Source
- 98 Replies
Dissected, but far from dead:
Here lies the nerve center of an essentially brand-new Technics SL-100c:
So... Where to begin?
Browsing eBay on a recent evening, I ran across a listing to the effect of, " !!PARTS!! Technics SL-100/1500 Tonearm, Platter, Motherboard, Otherboard. "
Okay, uhhh... [clicks mouse]
As advertised, the seller was parting out a "damaged in shipping" 100c that he'd purchased "as a return." After some back-and-forth, a story emerged: Apparently someone bought this $1k+ turntable on Amazon, stripped off the stock cartridge and then returned it in the original box (minus most of the original engineered packaging). As many likely know, there's sort-of a supply chain purgatory where (literally) billions of returned items languish for long periods before being either bundled and resold or trucked off to a landfill. Never did I imagine those items to include things like brand-new turntables with ultra-accurate coreless motors that hifi mags have been raving about.
According to the seller, the unit was basically loose in the box and took a beating in transit: Dustcover destroyed, tonearm badly damaged, chassis cosmetically irredeemable, and... motor working perfectly. Unable to stop myself, I bought the motor, platter and everything you see here for a few hundred bucks.
Why tho?
Well for one thing, I've since confirmed the performance: Assembled with the motor just sitting on my desk, the RPM iphone app shows the platter running at 33.34 +0.03, w/f 0.15% (and even better at 45). That DUSTS the belt-drive deck I spent a mint on five years ago (which frankly leaves me wanting in other ways as well). More than anything, I just want to get my hands into this. I lust after classic broadcast decks, and have long wanted to join the SP-10 club (yes, I've spent a lot of time on The Incredible Thread). But for a lower price-of-entry, and given the specs above, this seems like a pretty cool alternative challenge.
And before anyone asks: Yes, I'm a bit out of my depth. I know this will cost more than I think. I don't yet have all the tools I'll need. There will be massive research and a lot of trial and error. I know there's a lot I don't know, and I'm prepared for this to take a long time.
So all that said, this thread will serve as the build log.
It's getting late, but at some point over the weekend I'll post my progress so far, my overall plan, anticipated next steps, and a few questions for the forum.
Really hoping a few of Technics Heads (and other experienced folks) will vibe with this project, follow and advise.
Cheers!
Here lies the nerve center of an essentially brand-new Technics SL-100c:
So... Where to begin?
Browsing eBay on a recent evening, I ran across a listing to the effect of, " !!PARTS!! Technics SL-100/1500 Tonearm, Platter, Motherboard, Otherboard. "
Okay, uhhh... [clicks mouse]
As advertised, the seller was parting out a "damaged in shipping" 100c that he'd purchased "as a return." After some back-and-forth, a story emerged: Apparently someone bought this $1k+ turntable on Amazon, stripped off the stock cartridge and then returned it in the original box (minus most of the original engineered packaging). As many likely know, there's sort-of a supply chain purgatory where (literally) billions of returned items languish for long periods before being either bundled and resold or trucked off to a landfill. Never did I imagine those items to include things like brand-new turntables with ultra-accurate coreless motors that hifi mags have been raving about.
According to the seller, the unit was basically loose in the box and took a beating in transit: Dustcover destroyed, tonearm badly damaged, chassis cosmetically irredeemable, and... motor working perfectly. Unable to stop myself, I bought the motor, platter and everything you see here for a few hundred bucks.
Why tho?
Well for one thing, I've since confirmed the performance: Assembled with the motor just sitting on my desk, the RPM iphone app shows the platter running at 33.34 +0.03, w/f 0.15% (and even better at 45). That DUSTS the belt-drive deck I spent a mint on five years ago (which frankly leaves me wanting in other ways as well). More than anything, I just want to get my hands into this. I lust after classic broadcast decks, and have long wanted to join the SP-10 club (yes, I've spent a lot of time on The Incredible Thread). But for a lower price-of-entry, and given the specs above, this seems like a pretty cool alternative challenge.
And before anyone asks: Yes, I'm a bit out of my depth. I know this will cost more than I think. I don't yet have all the tools I'll need. There will be massive research and a lot of trial and error. I know there's a lot I don't know, and I'm prepared for this to take a long time.
So all that said, this thread will serve as the build log.
It's getting late, but at some point over the weekend I'll post my progress so far, my overall plan, anticipated next steps, and a few questions for the forum.
Really hoping a few of Technics Heads (and other experienced folks) will vibe with this project, follow and advise.
Cheers!
Noisy NAD 7240PE - how to diagnose issue?
- Solid State
- 28 Replies
Hi everyone - So I have this NAD 7240PE. It's an absolute beast of a receiver that I bought sight unseen from the other side of the country and it arrived pretty beat up. It was super dirty and dusty inside and noisy as hell and the seller proceeded to never return any of my messages 😅. Several of the largest caps had burst at some point and spilled their goop on the PCB, which itself has turned brown from heat in the amp section, it must have been run HOT a lot. The radio tuner side meanwhile is still green as a normal PCB and works pretty well even just using the built in FM antenna.
I switched out the busted caps and cleaned it up and it's working a lot better but there must still be some component(s) fried or something since the amp has a ca. 10 sec period at startup and turn off where it plays this kind of ground saw wave noise through the speakers similar to touching an input jack your finger. After that stops, there is still this random, intermittent popping sound in both channels underneath the audio signal but it decreases slowly until - when the amp is warmed up perhaps - the noise is gone. At this point, the amp works almost noiselessly and sounds absolutely superb.
I'm telling you, the combination of buttons called “Bass EQ” and “Loudness” really make this amp drive way more nice low-end from my two Artcoustic wall mounted speakers than my other, newer NAD C316BEE ever could. It also sounds much more dynamic and enjoyable, no doubt partly due to the pretty complex BJT-based Class G topology in which separate higher voltage power rails are switched to momentarily when triggered by a powerful enough input signal, ultimately resulting in higher efficiency and dynamic range I believe.
Anyway, in my search for knowledge that could help in diagnosing and fixing the issue, I came upon some 7240PE repair threads on here and some people (e.g. Mooley) seem to have the skillset and experience needed to diagnose this kind of stuff so here I am, asking for some tips on what to look into on this amp 🙂
I can record the noises in question if it helps, as well as measure anything with a multimeter. I also have a power supply and even an old analog Agilent Oscilloscope that I bought cheap from my old student job employer (ICEPower) as they had stopped using it in favor of the new digital ones. It has been sitting in a cabinet unused since because I have yet to buy some probes for it - which I will if it will help fix this amp!
P.S. Here's the service manual which includes the amp schematic on page 13 and here's also some technical info on how the Class G voltage switching works for those interested:
I switched out the busted caps and cleaned it up and it's working a lot better but there must still be some component(s) fried or something since the amp has a ca. 10 sec period at startup and turn off where it plays this kind of ground saw wave noise through the speakers similar to touching an input jack your finger. After that stops, there is still this random, intermittent popping sound in both channels underneath the audio signal but it decreases slowly until - when the amp is warmed up perhaps - the noise is gone. At this point, the amp works almost noiselessly and sounds absolutely superb.
I'm telling you, the combination of buttons called “Bass EQ” and “Loudness” really make this amp drive way more nice low-end from my two Artcoustic wall mounted speakers than my other, newer NAD C316BEE ever could. It also sounds much more dynamic and enjoyable, no doubt partly due to the pretty complex BJT-based Class G topology in which separate higher voltage power rails are switched to momentarily when triggered by a powerful enough input signal, ultimately resulting in higher efficiency and dynamic range I believe.
Anyway, in my search for knowledge that could help in diagnosing and fixing the issue, I came upon some 7240PE repair threads on here and some people (e.g. Mooley) seem to have the skillset and experience needed to diagnose this kind of stuff so here I am, asking for some tips on what to look into on this amp 🙂
I can record the noises in question if it helps, as well as measure anything with a multimeter. I also have a power supply and even an old analog Agilent Oscilloscope that I bought cheap from my old student job employer (ICEPower) as they had stopped using it in favor of the new digital ones. It has been sitting in a cabinet unused since because I have yet to buy some probes for it - which I will if it will help fix this amp!
P.S. Here's the service manual which includes the amp schematic on page 13 and here's also some technical info on how the Class G voltage switching works for those interested:
For Sale [EU] Pearl 3 and PSU
Hi,
I'm selling these fully populated and tested Pearl 3 board and its PSU:
130€ + shipping cost.
Damien
I'm selling these fully populated and tested Pearl 3 board and its PSU:
- Pearl 3 with Kemet capacitor, wima and Panasonic MKP cap, 1% vishay resistor and LM833 OPA on dip8 socket.
- PSU with Schaffner 2x18Vac transformer, CRCRC with Panasonic M and Nichicon VR with Wima decoupling cap.
130€ + shipping cost.
Damien
Scott A 426
- By Depaj
- Solid State
- 80 Replies
Hello,
First time here on Diyaudio.
Here's a quick intro before asking what really is on my mind.
I'm living in Lyon, France so you'll have to excuse me for a few mistakes from time to time.
I have been around audio from the 70's and 80's for a long time, the music as well as the equipment and recently I discovered the pleasure of opening them up and try to understand them a little more, repairing and recapping when needed. So I am looking around on the internet for nice pieces.
I currently have a Technics su 8080 with a pair of ditton 66 legends, a technics sl-B2, a teac UD-H01 dac and a philips CD 624.
As secondary setup I have a Dual Pa 5060 saved from being thrown away with technics speakers also saved from a horrible death, a technics SL-PG580A and an ITT turntable (quite rare apparently).
I'm here to learn mostly but will do what I can with my little knowledge to help.
So now the real deal, I'm looking for help with a Scott A 426 I picked up recently.
When I got it nothing worked so I started by isolating the problem : the power amplifier section. I checked all the transistors and most of them were shorted, never seen that much in one single amp. Also a few resistors and diodes were bad so I replaced everything (some with originals some with equivalents but same on both channels).
(the red circled ones have been replaced)
But after all of this the problem doesn't seem solved, I powered it up with a lamp connected in series and it lit up so there has to be something else.
I couldn't find anything so if anyone here has any idea of what could be causing this I would be very grateful.
Thanks
First time here on Diyaudio.
Here's a quick intro before asking what really is on my mind.
I'm living in Lyon, France so you'll have to excuse me for a few mistakes from time to time.
I have been around audio from the 70's and 80's for a long time, the music as well as the equipment and recently I discovered the pleasure of opening them up and try to understand them a little more, repairing and recapping when needed. So I am looking around on the internet for nice pieces.
I currently have a Technics su 8080 with a pair of ditton 66 legends, a technics sl-B2, a teac UD-H01 dac and a philips CD 624.
As secondary setup I have a Dual Pa 5060 saved from being thrown away with technics speakers also saved from a horrible death, a technics SL-PG580A and an ITT turntable (quite rare apparently).
I'm here to learn mostly but will do what I can with my little knowledge to help.
So now the real deal, I'm looking for help with a Scott A 426 I picked up recently.
When I got it nothing worked so I started by isolating the problem : the power amplifier section. I checked all the transistors and most of them were shorted, never seen that much in one single amp. Also a few resistors and diodes were bad so I replaced everything (some with originals some with equivalents but same on both channels).
(the red circled ones have been replaced)
But after all of this the problem doesn't seem solved, I powered it up with a lamp connected in series and it lit up so there has to be something else.
I couldn't find anything so if anyone here has any idea of what could be causing this I would be very grateful.
Thanks
For Sale Power supply for Miro's DACs
Hi,
I have some spare PSUs built for my Miro's PCM63 DAC. Schematic and layout attached.
2 independend sections (separate grounds), transformers for +/-5V or +/-12V outputs, 230V input. Tell me what voltages you need, I'll solder the transformers.
LDOs 7A4701/7A3301, pots for fine adjustment. Caps - Nichicon KZH. I am quite happy with them, no hum and very good PSRR. PCM63 DAC measurements:
So far I have 3 boards for sale, 65 Euro/pc + shipping.
2 black, 1 blue. Size 99x86x30mm
Connectors can be included upon request.
I have some spare PSUs built for my Miro's PCM63 DAC. Schematic and layout attached.
2 independend sections (separate grounds), transformers for +/-5V or +/-12V outputs, 230V input. Tell me what voltages you need, I'll solder the transformers.
LDOs 7A4701/7A3301, pots for fine adjustment. Caps - Nichicon KZH. I am quite happy with them, no hum and very good PSRR. PCM63 DAC measurements:
So far I have 3 boards for sale, 65 Euro/pc + shipping.
2 black, 1 blue. Size 99x86x30mm
Connectors can be included upon request.
What happen to LC Audio Technology? Acquisition by an other Company?
- Solid State
- 5 Replies
Attachments
ALPINE PDX F4 troubleshooting - bought 2 Ebay amps and both have bad channels
- By Touring185
- Car Audio
- 35 Replies
Attachments
For Sale iFi Audio NOS 6922 Vacuum Tubes GE 5670 with Adapters Equivalent
- By bigskyaudio
- Swap Meet
- 1 Replies
Attachments
For Sale JAN Sylvania 7308 NOS Vacuum Tubes Qty 2 Matched Pairs
- By bigskyaudio
- Swap Meet
- 3 Replies
Attachments
Project IV: USB sound card with Hi-End twist
- Digital Line Level
- 13 Replies
Hi folks,
For decades I’ve been dreaming of making digital audio system which would sounds indistinguishable from a good quality analogue one (based on tape or vinyl media).
But only recently it became feasible to build such a system for the reasonable amount of money, thanks to the new AD and DA converters (and other supporting chips) on the market.
Long story short – here is my first humble attempt, I called it Project IV.
Generally, it’s a two-channel AD-DA converter (ADAC) built with high-end philosophy in mind and utilising industrial-grade ADC and DAC chips with good metrological parameters.
The ADAC board itself has balanced inputs, balanced and unbalanced outputs and supports 44.1, 48, 88.2, 96, 176.4, 192, 352.8 and 384kHz sampling rates.
Special steps were taken to reduce system jitter, including low phase noise Crystek 957 series oscillators and 13 low-noise linear LDO regulators on boar, mostly LT3042.
XMOS based DIYHK board is used as USB to I2S interface. Xilinx CPLD converts I2S signals to SPI interface, needed for multibit DAC, and forms sampling logic signals for SAR ADC chips (LTC2380-24).
While looking for information and app notes on LTC2380-24, I have come across very interesting project of Frex: https://www.diyaudio.com/community/threads/osva-open-source-versatile-analyzer.335005/
Highly recommend that thread for those thinking to use LTC2380-24 in their projects.
In my case ADC converter is always working at 1.536MHz for 48k band (or 1.412MHz for 44.1 band) sampling frequency. For 384k, 192k, 96k or 48k output LTC2380-24 chip does 4, 8, 16 or 32 averages respectively, thus improving S/N ratio. The same happens if 44.1k band is selected.
For DAC section I have selected 20-bit AD5791 (or 18-bit AD5781) chips. The reason is that since 2003 I love to use the following topology in my DACs:
It allows me to built a DAC with no feedback in any part of sound path, including reference and output buffer. Decades of intensive use has proven very good musical characteristics of this topology. And AD5781/91 chips have unbuffered R-2R matrix with no OP amp on the output.
Nevertheless, current PCB is allowing to use traditional schematic with high-quality OP amp buffers.
Overall view of the finished board is shown below:
I have done some preliminary measurements of ADC section using low-distortion generator from (again!) Frex (https://www.diyaudio.com/community/...-10khz-oscillator-new-updated-version.287892/).
Found them quite satisfactory:
The next step now is to built tube buffers for ADC and DAC, so the work is in progress…
For decades I’ve been dreaming of making digital audio system which would sounds indistinguishable from a good quality analogue one (based on tape or vinyl media).
But only recently it became feasible to build such a system for the reasonable amount of money, thanks to the new AD and DA converters (and other supporting chips) on the market.
Long story short – here is my first humble attempt, I called it Project IV.
Generally, it’s a two-channel AD-DA converter (ADAC) built with high-end philosophy in mind and utilising industrial-grade ADC and DAC chips with good metrological parameters.
The ADAC board itself has balanced inputs, balanced and unbalanced outputs and supports 44.1, 48, 88.2, 96, 176.4, 192, 352.8 and 384kHz sampling rates.
Special steps were taken to reduce system jitter, including low phase noise Crystek 957 series oscillators and 13 low-noise linear LDO regulators on boar, mostly LT3042.
XMOS based DIYHK board is used as USB to I2S interface. Xilinx CPLD converts I2S signals to SPI interface, needed for multibit DAC, and forms sampling logic signals for SAR ADC chips (LTC2380-24).
While looking for information and app notes on LTC2380-24, I have come across very interesting project of Frex: https://www.diyaudio.com/community/threads/osva-open-source-versatile-analyzer.335005/
Highly recommend that thread for those thinking to use LTC2380-24 in their projects.
In my case ADC converter is always working at 1.536MHz for 48k band (or 1.412MHz for 44.1 band) sampling frequency. For 384k, 192k, 96k or 48k output LTC2380-24 chip does 4, 8, 16 or 32 averages respectively, thus improving S/N ratio. The same happens if 44.1k band is selected.
For DAC section I have selected 20-bit AD5791 (or 18-bit AD5781) chips. The reason is that since 2003 I love to use the following topology in my DACs:
It allows me to built a DAC with no feedback in any part of sound path, including reference and output buffer. Decades of intensive use has proven very good musical characteristics of this topology. And AD5781/91 chips have unbuffered R-2R matrix with no OP amp on the output.
Nevertheless, current PCB is allowing to use traditional schematic with high-quality OP amp buffers.
Overall view of the finished board is shown below:
I have done some preliminary measurements of ADC section using low-distortion generator from (again!) Frex (https://www.diyaudio.com/community/...-10khz-oscillator-new-updated-version.287892/).
Found them quite satisfactory:
The next step now is to built tube buffers for ADC and DAC, so the work is in progress…
Attachments
Scrap DAC (PCM1710U & Cs8412/14)
- By mot on/off
- Digital Line Level
- 7 Replies
Happy new year everyone!
All the best! 🙂
As i didn't have any luck with my previous project (Vestax cdx 12) i decided to up-cycle the DAC of the Vestax.
Not that bad, not that good but i'll give a try.
BB PCM1710 used in several PC players and also in AN cd1.
As i'm gathering information about schematics im nearly at the end of the pcb.
It will be quite simple according to the two schematics describing all the necessary connections between CS8412/14 + PCM1710.
The only thing i will need some help is Pin 16 of Cs8412/14.
I'm thinking it will be great to have a sampling frequency indicator & error indicator (both in leds)
I've found a nice Cs8412 spdif indicator
In this case SEL (pin 16) is LOW so we can have error/frequency info selected according to datasheet.
I was wondering if with SEL in LOW we can enable de-emphasis also.. Seems not but a person with greater skills may know better.
Also how can we add the 96Khz sampling freq. in case we use the pin compatible 8414?
And the pcb so far..
Thank you all 🙂
All the best! 🙂
As i didn't have any luck with my previous project (Vestax cdx 12) i decided to up-cycle the DAC of the Vestax.
Not that bad, not that good but i'll give a try.
BB PCM1710 used in several PC players and also in AN cd1.
As i'm gathering information about schematics im nearly at the end of the pcb.
It will be quite simple according to the two schematics describing all the necessary connections between CS8412/14 + PCM1710.
The only thing i will need some help is Pin 16 of Cs8412/14.
I'm thinking it will be great to have a sampling frequency indicator & error indicator (both in leds)
I've found a nice Cs8412 spdif indicator
In this case SEL (pin 16) is LOW so we can have error/frequency info selected according to datasheet.
I was wondering if with SEL in LOW we can enable de-emphasis also.. Seems not but a person with greater skills may know better.
Also how can we add the 96Khz sampling freq. in case we use the pin compatible 8414?
And the pcb so far..
Thank you all 🙂
