Looking for opinions. I'm a new owner of a Denafrips T2 DAC. Interesting piece, what is also interesting is their choice of WIMA caps. MKS from what I can tell are used in the filtering section, and I think FKP on the output. I've had mixed to poor results with WIMA polyester in the past, maybe in the filter section they might be ok, augment/bypass the electrolytic bank, but on the output and/or coupling the DAC resistor ladder, I would have chosen different if I were designing maybe.

Interested in opinions. I was looking at some Charcroft Audio Silver Mica as a possible FKP replacement, fitting MKP will be tough and wouldn't want to make a mess of it visually. Some polys in the filter section would have been nice, what are the thoughts on this? It's as good as it gets with WIMA MKS/FKP?

Some might remember my proof of concept using CDSP as a preamp. My initial tests sparked this DIY Amp project. I thought it would take some time but not this long! I wasn't even sure it would work but since its playing right now I thought I would share this build and my experiences from it. It will take several posts to cover it all so I thought I break it down into the following topics:

• Background
• Concept and Design
• Hardware Selection
• Fabrication
• RPi 2040 Pico and Controls
• HiFiBerry DAC+ ADC and UR23
• RPi Zero 2 W and CamillaDSP
• Final Thoughts

The background is already more or less covered by my proof of concept post. I will post the rest in this thread as soon as I get the time to put each piece together. Until then, a couple of images of the final amplifier, front, back and besides my custom built TD-115.

I just uploaded the best Rock songs from my Collaborations albums. Here's the link.
Login to view embedded media

Been way too long and missing many wonderful things happen in the forum
to busy sorry to say .
Most of you know that i currently construct P3A and allready produced 5231 different PCB implementing mods and different styles .
2026 will be 20 years ( man time flyies ) that i am doing that .....

So since i am having a brake from too much work ( had a really rough last year concidering volume of work ) i am willing to construct once more but this time with regulated rails or capacitance multiplier ....

Quad did in the past , Naim did in the past and soon (since classAB is a dead end ) we will see one of the big names of hi end comming with one machine ( range 50K ) that will be a typical hi end class AB ( includes extreme enclosure style and loads of transistors ) but this time with IGBT regulated rails .

Question is that if anyone thinks that is going to be any audible benefit from that ?
Question is that if this benefit will apply from low listening level till clip ?
Question is regulated rails or capacitance multiplier and why ?

My only previous expirience was with QUAD wich the all thing was single rail, capacitor coupled, sorry excuse of amplifier circuit .
BUT !!, people that used them actually as pro amps in small bars said that they sound very good , amplifier is indestructable and impossible to destroy a speaker with it ... ( probably this has not much to do with regulated rails , but mostly because is capacitor coupled )

Place your comments please
i will be more than happy to listen

thank you

hi, I'm making a stabilized power supply for tube filaments, it's a line + phono preamp.
I'm undecided whether to rectify with a mosfet bridge (lt4320 + mosfet in attached photo) or use 4 sic to220 diodes.
Which solution is less noisy? After the bridge and cap there is a lm350k or lm338k.
Thanks

I have a technical manual on guitar electronics entitled "Electric-Guitar Data and Analog Circuit Collection".
It's totally free and contains lots of information not normally found in design-build books.
Electronics techs and engineers are welcome to point out any errors I may have made. Post here or email me. hkurtrichter@gmail.com
Here's the link. Onsite click "File Share" at upper left to access PDF files with various sections of the book, and other information.
https://hkurtrichter5.wixsite.com/electric-guitar-data

Hi, I have this Rega Elicit R which was bought brand new and was working ok. However, after a year of low use it started having this problem of going silent with a click following fifteen to twenty minutes of music play. If I shutdown the amp and turn it back on after a few minutes, the amp would play but again become silent with a click after a few songs.

From the beginning the unit would run pretty hot, maybe some part inside has become weak. I am currently in a country where there is no Rega service center. Let me know if anyone has any idea about what is wrong with the Amp and how to get it fixed.

Thanks.

... only that this time it's me and not another new forum member.

So, let me introduce me briefly. I'm a tinkerer out of Germany (but I do like to pretend to be out of Palau because of .... reasons) and long story short: In the last months I've switched to a low budget CLASS-D amplifier setup (Fosi Audio V3 stereo & SMSL SU-1 as a DAC) ... but as this setup won't allow me to hook up my turntable (Refurbished & upgraded Metz Mecasound TX-4963) and I still have two Marantz power amplifiers in my possession. (Marantz PM4200 & Marantz PM-35 MK.II) I simply had the idea to repurpose the old amplifiers.

As it turns out, the Marantz PM-35 MK.II has several modular PCBs instead of one all-in one PCB ... I'm currently chasing the idea to strip down the Marantz PM-35 MK.II, removing it's original PSU & power amplification board and converting it to a preamplifier or better said a input source selector & phono stage, rehousing it's guts into a smaller chassis. Instead of just buying another source selector & phono preamp (Which would be convenient, indeed. But that won't satisfy the little tinkerer inside of me.)

So my main intention to post here, is to get some help in understanding the schematics of that amplifier (available here) or at least an educated opinion if my idea is practical or does require more effort than I actually anticipate. At least with the schematics I'm currently out of my comfort zone, and therefore I'll need some advice.

Therefore, I'll open another, dedicated thread to this project. Unless someone convinces me that it's a bad idea to repurpose that old amplifier with it's MM/MC capable phono stage.

So far for now, enjoy your weekend ! It's a beautiful and sunny day where I'm at and I hope it's the same at your location !

Building the F5 Turbo v2

This is the "in-progress" thread for the official build guide of the F5Turbo. This is not the final guide.

I am building a V2, with 2 outputs per side, source diodes, and no cascode. DIYaudio store PCB are being used and it will all go into a 5U 400mm "BIG Amp Chassis"

The Firstwatt F5 Turbo article from Nelson Pass, in case you haven't seen it - www.firstwatt.com/pdf/art_f5_turbo.pdf

Anyway, on to the build. 🙂


The Chassis in the shipping box and the PCB.


While we are at it, here is a good photo of the Front-end board


And here are the output boards. The component numbering on all these boards don't quite match up with the schematic, that will need to be clarified in the guide. In the time being, a bit of logic and inspection will let you figure it out.


A large transformer. 🙂



Building the PSU -


Components - PCB, Caps, resistors, thermal shutoff, inrush limiter, line cap, ground loop breaker, rectifier diodes. Not shown are rail LEDs, bleeder resistors.
Why 2 PCB? to hold the (16) 10,000uf 50v capacitors. 🙂


We will only need one Bridge PCB, and the rest can be cut off the boards.


The PSU will be built on the 'DIY friendly' baseplate, shown here with some of the chassis hardware.


The first PCB will hold only caps and the filter resistors. But there is only room for eight, and the board holds fourteen…


So a bit of stacking is required.




The other board will have the LEDs and bleeders. Please note that the resistor pads must be jumpered.


Testing the LEDs with a bench PSU


The 2 PCB now stuffed. The left will have the input from the rectifier, the right will be the output to the amp.


The other side of the PCBs


Looking down at the first PCB


Looking at the second. Again, please note the jumpers where there are the resistors.

Good evening, I was looking for some information, in particular if anyone ever created a 3D model for making a custom component in EasyEDA.
I would like to know the 3D/CAD program best suited for this.
I know how to use Blender3D quite well but I have no idea if it's possible to later on import it into EasyEDA easily, one would think that solidworks/autodesk fusion would be more suited for this. Did anyone ever try?

Regards.

Although the regulation circuit is physically connected to the incoming mains, it is disconnected electrically. A monitoring circuit detects the portion of the sine wave that is charging the first of a pair of electrolytic capacitors. Once this first capacitor is fully charged, the diode bridge rectifier turns off and a mosfet switching circuit transfers the charge from the first cap to the second. This cycle is repeated continuously.

Output voltage: -0V - +22Vdc, 0V - -22Vdc

• Output current: +/- 0.5 amps dc
• Mains: 3 Pin IEC moulded (socket on rear)
• Mains Voltage: 230Vac

Enclosed are files of a VituixCAD simulation of a notch filter and a Zobel element - I want to tame the breakup modes of an actively driven Purifi PTT6.5X04-NAA-08 6.5” aluminum midwoofer. Is my approach okay? Thanks for your contribution!

I like putting handsome indicator LEDs like the one below on the front panel of stuff I build.



But I also like those lovely 10mm thick brushed aluminum front panels from Modushop.

Problem is: I’ve not yet found an indicator LED with threads long enough to reach all the way through the 10mm panel. On my last amp I drilled out a massive hole to fit the nut into. It’s still very hard to fasten & unfasten the LED.

How do you folks attach panel-mount LEDs to thick front panels? Or do you? Hs anyone found a panel-mount with 12mm thread? Snap-ins that work? What about T-nuts which can be turned with a wrench?

Any clever ideas?

Hello all,

I apologize for what is likely a duplicate post, but I am unable to post in the tubelab forum (which is why I registered) until I generate "four meaningful posts" so I am trying to come up with questions to ask- even though my first inclination is to watch and search and lurk!

I am considering buying a tube tester to make my future hobby a bit easier. First thing I am working on is a StroboConn tuner (a bit odd, but it will be useful at my job) and it has the original Conn (re)branded tubes I would love to keep and even use, if they are working right. I can drive a few hours to a friend's place to use his tube tester, but it seems like I might want one for myself if they are not too much of a can of worms.

Questions: Any recommendations? Hickok seems to be a standard. Are there ones to avoid? What should be expecting to pay? Are they easy to fix if they are not in perfect condition? What sorts of issues should I expect, or look out for? Where to buy? I've been looking at ebay. Any recommendations or words of wisdom?

Thank you for your time, and again, sorry if this is a duplicate post but I am unable to post in the tubelab forum until I engage more.

Hello, I'm Allen I like DIY Hifi DAC and UAC2 interface . I found in diyAudio forum there are so many people like me .
People here are kind and discuss technical freely . I'd like to join the group.

I have tried to upload pictures from my phone but the picture does not show in the picture box in the file attachment.
Is this a known problem.
Steve.

I'm working with a audio isolation transformer and it hit me, how exactly does a audio transformer maintain a flat frequency response when by definition an inductor is frequency dependent. I'm guessing its a simple answer and I Googled it but no good hits. Ether way, I thought it was an interesting question.

Thanks
Micheal

These are the MK2 version i believe (From 1987). It's common to re-foam the midranges on these, also common to re-cap the massive crossovers. Both of which I've already done to mine!

But upon removing the tweeters, i noticed a strange brown stain on the stickers that show the brand name... I couldn't help myself, and took one of them apart very carefully, and guess what? Ferrofluid! Nasty, crusty old ferrofluid to be precise.

I tried asking around, and of the many people that work on these towers, NOBODY i asked knew that those tweeters used ferrofluid. I even emailed B&O, and they were surprisingly helpful! But even they had no real idea on how much fluid went into those tweeters. So i'm looking to just swap them out with more modern ones.

Turns out, this isn't as simple as it sounds. I've had replies going from "just buy some cheap tweeters and slap them on, you might get lucky!" all the way to very scientific replies that i barely understood...

They are ferrite, silk-dome tweeters. No idea what brand tho, the midrange drivers can be made by Nokia, SEL or ITT. Depending on the position of the moon it seems... I have a suspicion that the tweeters are made by SEAS tho.

So, what are my options here? Just eyeball the ferrofluid and hope for the best? Or try to replace them with modern tweeters, without knowing a damn thing about the specs of the old ones?

As i'm typing this, i'm also going to send an email to the owner of Audiofriends. I've bought all my Penta repair stuff from them, perhaps they'll know the true specs of the tweeters.

Any input is appreciated!

I have on the bench a Conrad Johnson SD-1. It is based on the Magnavox FD2041. All the literature I can find says it uses a standard CDM2 transport. This one has no stickers on it and I am trying to determine which Pre-amp Servo board is in use. Virtually every SM I have read shows a 1K laser output adjustment pot at 3106. This board has a 4.7K pot. I have seen that pot used in CDM4 but not CDM2 before. I am trying to determine which version of the board this is. I attach a picture and wonder if anyone has any insight.

Hi, just got into diy stuff with audio and need some help!

This five resistor load bank can be adapted for audio by dividing all of the resistor values by 100.
Then the values are 10 ohms each, and the total load can be adjusted among 12 values, from 20R to 2.5R.
Choose the power rating of the resistors for your needs..

https://www.electronicdesign.com/re...step-resistor-load-bank-is-simple-and-modular

I have 21 x 2SJ50 HITACHI and 22 x 2SK135 HITACHI. They are around 30 years old and have not been used since then. These lateral Fets are fames in many amplifier output stages. Minimum purchase is 4 pairs of Mosfets. Offers are welcome. Clear up my semiconductor collection of the ones I don't need anymore.

The price does not include PayPal and shipping costs. Can only shipped from Germany , prices are much lower above 200gr Parcel weight. PayPal is accepted, only registered shipping possible, the buyer pays the additional 5% PayPal fees, a payment as PayPal / friend does not account for the 5% and can be shipped without tracking, the shipping costs within the EU are about €15 - €17. Outside the EU it may vary by country. A combined shipping is possible but will change the shipping costs a bit. If you are interested send me a PM.

Many of us have a stereo microscope for soldering SMD, and the first idea comes to use that to inspect silicon chips and transistors to make sure it is not fake and the same version of what you are looking for. However, the result is always awful, and how can I see now, the reason is a coaxial light option which is unavoidable and needed to get perfect pics of silicon. The magnification factor nearly doesn't matter, my stereo Nikon SMZ660 has 300x max but still sucks due to LEDs light falling with not 90 degrees - glossy reflections ruining the picture contrast.
So, Is there any chance to get nice pics without $5000 Zeiss metallurgical microscope? Hell yeah, quite compact and within $100! First I bought a used VSZ-0530CO Japanese precision optical zoom device $53(with 12V coax LED!), it is a machine vision element massively used in China to control production parameters and measure dimensions. Vital Vision Technology promises a good resolution(4um) and minimal geometric distortions(.001) for the device, you need just add the C-mount CMOS camera 1/1.8"(from $30 for a secondhand) and 160mm RMS standard 4X lens aka objective(I paid $8 for used Canadian Motic EF plan 4X/0.1) with a thread adapter($4). The small like a book table + holder cost me $15, that's it. Check this out:


Low phase-noise EPSON_SG-210STF oscillator chip.

BC856B

AD8397 is a bit dirty with the residual plastic on the silicon.

Ti ISO7240


OPA1612 has such a tiny marking, the symbol's thickness is 4um, and the minimal visible elements are 1.5um. That pic taken with Motic 40X lens.


And a short video 30fps 400X, to see how that looks online.

Hello,
I build tube amps for fun. I wonder about the origin of the components, I live in France. For electrochemicals there is F&T, but the ripple current and the lifespan are much lower than Pana ED model 47uF for exemple.

I am attaching a 5E3 type diagram to have a power supply in front of me.
What characteristics would be preferred please?

Tell me more !

Pana ED
https://fr.rs-online.com/web/p/condensateurs-electrolytiques-aluminium/4340380?gb=s
https://www.mersen.com/fr/produits/condensateurs

So I have this transformer that has 2x 6.3vac/5A + 2x 6.3vac/1.5A and am wiring it to have 2x 6.3vac/6.5A.

I plan to use the LT1083 to regulate to 5vdc and feed 2x 300B per channel. It's a 4x 300B P-P amp.

I wonder if my plan is feasible or the 6.3vac is a bit too low for 5vdc output?

I have two Vifa D26TG-35 tweeters for sale. These have been in storage for quite a while, but works ok. $150 for both + postage. Located in Australia, but can ship to anywhere if postage is covered.

Following previous posts on the “Ship of Theseus” thread around here https://www.diyaudio.com/community/...ngeable-amplifier-modules.383745/post-7437999 [stopping to avoid derailing the specific amp topic], here is a follow-up, in the Parts section, which might be more appropriate: heatsink = parts
The post shall serve as a reminder for myself, and maybe it would be usefull to others at some point.

After the original posts, here is what I learned

A. [from a discussion with a thermal engineer @work]
Outside heat exchange coefficient of h=20 w/(m²-C) was probably too optimistic. h=15w/(m²-C) might be better

B. [from the same discussion]
*Imposing temperature is like imposing a constraint for a mechanical calculation. It is better to impose a thermal power released by the transistor to calculate a state of equilibrium between power released by the transistor and power dissipated by the heatsink.
*He suggested Thermal Power = Electric Power as a starting point.

*Since M. Johnson indicated that each transistor of the Theseus should give about 30watts (approximation), I set a thermal flux of 93750 watt/m² for each roughly 20mm*16mm transistor surface. 93750*0.020*0.016=30.

C. [air temp measurement with an M2x 4U 400mm]
Different circuit & heatsinking, but it is what I have
Ambiant air temp: around 20/25degrees
Air temp inside the amp after 1h: 45degrees
Air temp between the fins after 1h: 35degrees.

This to put an approximation of temperature for the convection in the various calculation. (I was using much higher inner air temp: 65degrees before)



Using this with the “Ship of Theseus” reference, transistor located on the left side (6L6 here https://www.diyaudio.com/community/...ngeable-amplifier-modules.383745/post-6958070), leads to the following results (picture)
What is worth noting is the different in temperature between the 2 transistor surfaces, the one on the right being colder, most probably because he “sees” a bigger chunk of the heatsink.

Lower temperature of 42degrees indicates that the heatsink participate to cooling the inside (I guess)

I have a grado ME+ mono for playing 50's+ mono LP's & have a few different arms from older Ortofons, an SME 3012 to a formula 4 unipivot. Also an LP 12 with a Fidelity Research arm.
I assume the heavier arms would be better. - This for playing a good classical LP colection in VG condition from my father, - Decca's, Mercury, Phillips, RCA etc.

Any comments?

Thanks,
R.

Hey all! I'm back after a long hiatus.

Well... just a thread to say that at last I finished my JLH 10Watter last weekend... I dicided to buy a commercial lab-powersupply.. this made things alot easier..

The results: Great!

Sound is a difinite upgrade from my Sony integrated amp .. more instruments are comming through even in loud part of the music.. high's are excelent .. well at least for me they are.. and supprisingly the bass somehow has more detail.. I experienced the new sound like I experinced my first Grado headphone listeing, but now with the stereophonic effect working..

The amp was easy to build, I even flipped a transistor around but the amp still worked.! just a little noisy.. Iq is set at 1.2A@ 27Volt, the 4 heasinks get hot but can be touched for more than 10 seconds.. well permanent actually higher voltages and Iq goes really hot!

10Khz square wave looks crystal clean but a 50KHz reveals the assymetric slewrate.. bandwidth goes from 10Hz to beyond 200KHz...

conclusion are that it is a very simple amp to build, no PCB used, no instability of any kind.. and sound is quite revealing.. highly recommended

but then again, my initials aren't H.H. 😉

I want to examine the sonic virtues (?) of an OPA627 for myself, however genuine OPA627's "seem" getting hard to find at less than $40 each from Digikey. To test the parts out what is the resistance between pin 5 and pin 7 of a genuine part? Pin 5 is normally one of the input terminals for an external offset trimmer (the other is pin 1 as ought to have the same resistance value). Both ought to be connected to the positive supply if the part is genuine.

Thus far alleged "genuine" parts have resistances connected to the negative rails, or appear on the wrong pins.

This is a self-bias amplifier that allows you to replace beam tubes and pentodes from 6L6GC to KT170 without any adjustments.

Equipped with an output transformer from Hashimoto Electric, a proud Japanese manufacturer, and a V-Cap coupling capacitor, this lavish upgrade promises high performance and sound quality that far exceeds the original model.

Maximum output is 40W for KT88 and 45W for KT170, and it operates in Class A at regular levels, with a focus on sound quality.

This is a high-cost performance model that allows you to enjoy the essence of Japan quality, with a high signal-to-noise ratio, wide frequency response, and excellent damping characteristics.

SV-P1616D/VK Pentode Power-amplifier
Hashimoto version HW-40-5 kit 120V/240V
NO Volume Pot
Point to Point assembly


The production version will get rid of the volume port and replace the stock opt to Hashimoto H40-5
KT170×4 ECC81/12AT7×2 ECC82/12AU7×2 ※Tube set is an option
Rated output: UL connection (Class A operation up to 50% of rated output)
（8Ω、THD：10%）
　KT170 45W+45W
　KT150 37W+37W
　KT120 37W+37W
　KT88 35W+35W
　EL34 33W+33W
　KT66 25W+25W
　6L6GC 22W+22W

　
Frequency reponse ：5Hz～150kHz(1W/8Ω/-3dB)
Gain：27～29dB（8Ω）
size in mm：W365×D300×H190

You will notice that the output transformer has been replaced by Hashimoto HW-40.
All aeesembled version be will instaled with 4X Vcap ODAM coupling caps

PRE-ORDER Pricing​

KIT $2,150 (point to point kit)​

Assembled $2,750 (Made and Assembled in Japan with 4 VCAPs ODAM)​

TUBE SET EXTRA​

It would be premature to think that anyone can just change the OPT... The output transformer affects the overall characteristics as much as a car engine. In cases such as a single triode with no feedback, it may be possible to replace it by checking the impedance and core capacity, but in the case of a push-pull amplifier with a large amount of feedback, in the worst case scenario, the amplifier may oscillate and be damaged, so careful consideration in advance and detailed measurements after replacement are required.

The original output transformer is a custom-made product (made in Japan) optimized for the SV-P1616D and has KNF (cathode NF) windings, but the OPT to be installed this time does not have KNF windings. NFB is established based on the delicate balance of the amplifier, so the design is very delicate and design changes are required.

According to the report of the craftsman who was commissioned to make the prototype, the default NF resistor and phase compensation capacitor capacitance caused oscillation outside the audible range. This is something that cannot be detected by ear and can only be detected by measurement, so special care is required. As a result, integral compensation was added to the secondary side of the OPT to ensure stability and the project was completed.


I accept preorder

A Happy New Year to all.

I decided to start a new project, called "FreeDSP-G" as an Electric Guitar Amplifier Simulator Project.
I previously tested the Amp-Simulator implementation on FreeDSP-OCTAVIA. It was good to learn the potential of SigmaDSP processing. The most critical point was the available number of control pots. However, multiplexing AUXADC will solve the issue. So, I established a concept design drawing as below.


ADAU1467 will fit this project. It has 8 AUXADC and additional many GPIOs.

CyberPit

David Lettermen used to have a feature on his Late Night Show called "Stupid Pet Tricks." It's basically what it sounds like; pets doing pointless things.

Something I've noticed in my experiments with ATH, is that my results generally pale in comparison to everyone else, but I'm often doing strange things with the waveguide, just to see what happens.

It's hard to track my weird experiments in the main ATH thread, because there's so much traffic. I made the posts and I often have a hard time finding my own posts.

So I thought it might be fun to post some weird ATH waveguides, basically to evaluate what would happen if you made something strange.

Over the years, I've struggled to make a waveguide with a diffraction slot that actually works; most of my experiments with ATH and IRL haven't really panned out. Diffraction slots have a LOT of issues.

Then again, I found that triangular waveguides work shockingly well, even though I've never seen anyone actually build one IRL.

Hello All,

I’ve been doing a lot of reading on the forum the last few weeks, and I first want to thank all the contributors for the wealth of knowledge here. Amazing online community!

I got a pair of blumenstein orcas last year to go with my Bottlehead SEX, 2wpc set amp. I am digging the low power-single driver sound! But when I moved from near field into a larger room (270 ft2, 12ft ceiling) they started to feel too “small”. I don’t have an extensive audio vocab, but I believe I want more bass extension and higher sensitivity, all in a smallish package (can be bigger than orca though). Seemed too much to ask, but after some reading I fell in love with the OG Fonken with fe127e driver. However the drivers are no longer available, and it seems Ff125wk may not be sensitive enough for my flea powered amp. I am eventually looking at adding a sub.

Any suggestions? Or anybody have the old model driver laying around?

Thank you,

Noah

Hello all, so I had the output on the T751 drop to nearly nothing. There was a previous issue and I replaced the surround board. Everything worked fine since then.
I just decided to try and fix the new issue and am stuck.
I re-capped the entire front amp board.
I pulled each of the main transistors at the bottom and they all seemed to test OK off board.
I seem to be getting proper voltage at the opamp on the load board, and proper voltage out to the front amp board. If I turn the volume up very high, I can hear the source a bit, but it's very faint.
Problem persists through headphones.
Sound completely gone if I change listening mode to anything but stereo.
I'm not sure where I should be focusing my effort now. There are a bunch of smaller transistors on the board I didn't check yet as it would be pretty time consuming to take them all out of circuit.
Any direction would be appreciated

Hello, I am 53 years old and came across this forum while researching and trying to get a better understanding of audio amplifiers.
I love restoring vintage electronic/electrical items in hopes of "bringing it back", repurposing and keeping
it out of the landfill. Thanks for such a great website!
p.s.- The more I think I know, the more I realize how much more there is to learn..

I've been trying to trace an issue with my NAD t751.
1. Extremely low volume output on both left and right channels
2. No output when surround mode selected.
3. Doesn't matter if headphones or speakers
4. Doesn't matter which input.

I've bought an oscilloscope and I THINK I've traced it to the multichannel board. Audio goes from inputs to this board, then sent to the amplifier boards.
I get a signal from my freq generator to the input of the "m62447sp" IC.
It seems that the output pins of this chip are dropping the signal. Is this how it's supposed to operate or should the volume be increased and maintain waveform?
I'm not sure if I've just found the issue or if I'm misunderstanding this IC.
See attached docs.

Hi everybody,

I'm trying to repair a luxman d-05u.
The issue is that it doesn't read SACD's anymore, CD's are playing flawlessly.
I suspect the laser to be the cause of this issue, my SONY SCD-555 showed the same issue and replacement of the laser was the solution.

• Does anyone have a service manual or schematic available?
• Does anyone have experience with this specific player showing this issue?

Best regards,

Bart

I want to make a pair of tower speakers. I am at the beginning of the project, choosing the speakers and crossover. Since I am a beginner, I chose a set of speakers that can be bought with a crossover. In my head, this crossover comes ready to use with this set of speakers (please correct me if I am wrong). What do you guys think of it?

Crossover: Swan DN-CE5.1F
Low mid-range: Swan E6.5
Mid Range: Hivi DM-7500
Tweeter: Hivi Q3B

The reason why I chose this set was because I found them at a good price in a store in China. And of course, because I think they come with a sort of ready-to-play crossover.

Hi!

Continuing from the "main thread" I wish to discuss and get help of implementing an infrared (?) remote control that can do:

• Volume + / -
• Mute
• Play, Next, Pause
• Change config
• Tweak a PEQ parameter

Platform Pi5 and pCP picoreplayer with CamillaDSP.

As I understand it, I need:

• Pi5
• Power
• An IR receiver eye
• A remote - preferable the small metal Apple remote or the like.

I can hook up the IR to the Pi but then its get foggy ;-)

Please help!?

//

I'm new to vintage audio and looking for tips.

_____ **___This giveaway ended on March 16, 2025 __**_____

Congratulations to Abx74 as the winner!!!!







Everyone loves a good giveaway. This giveaway is Honoring our diyaudio colleague Mark Ozdoba { @Toys4Boys }, who passed away in September of 2024. Mark and I both got into diyaudio around the same time, and we made a connection as we learned and shared knowledge building our first Pass DIY amps.

This is in fact Mark’s F5m kit (Essentials, Completion, PSU) and I’ve added in nearly all the additional parts to finish a complete amplifier. The only items needed are a chassis and a transformer.

Mark would love knowing his kit (which is from the first round of kits sold in the diyaudiostore in March 2024) would be built, so it can play glorious toe tapping tunes.

I’m politely requesting that this go to a newer builder. Please don’t enter if you have a stable of amps. It would be great to see this go to someone who’s relatively new to diyAudio that would benefit from all the additional bits and pieces included.

I will cover shipping in continental USA and will take off $10 from total shipping cost for international shipping.


To Enter: Just copy the list in the most recent post, add your diyaudio surname/alias at the bottom of the list, and post (country is optional, always fun to know where you reside)

Rules: I will leave this open for one week. On the evening (in Seattle, USA) of St. Uhro’s Day I will enter all the names into a spreadsheet and randomize. The entrant at the top of the randomized list will be the winner.



Here’s what is included:

• F5m Essentials Kit (PCBs, JFETs, & MOSFETs)
  • Also includes 4qty Keratherm 86/82 Insulator pads, 4qty 3/4" fender washers, belleville locking washers, and M3 bolts to secure MOSFETs to heatsink
• F5m Completion (all the parts to complete the F5m PCBs and additional hardware)
• Nelson's V0 PSU Kit (all the parts to complete the PSU)
  • 2qty 4.7ohm Epcos B57236S0479M000 thermisters included for higher biasing using the V0 PSU board per F5m article
  • 2qty rectifiers (non metal case)
  • Rhthatcher snubber PCB
    • 2qty 0.15uF, 2qty 0.10uF film caps, and 2qty 22R resistors (ideal for Antek AS series)
  • Rhthatcher soft start board (technically this isn’t necessary, but included to make hookup easy)
    • 6qty male 0.250" spades, 2qty CL-60 10R thermisters, & 3300pf X1Y1 safety cap
• 3D Printed Transformer Seat Kit (works with 300VA or 400VA Antek AS/AN series)
• LEDs for front panel with wires already attached and 22k resistors (blue of course)
• Neutrik NF2D RCA inputs (silver body with one black RCA, one white RCA)
• Power Entry Module (Shurter 4304.6090)
  • Includes 2.5A, 3A and 10A fuses
  • Premade 14Ga Safety Ground Pigtail with eyelet and 0.187” female spade (soldered on to PEM)
  • Twisted heat shrink 16Ga AC mains wires with 0.187” spades installed for PEM connection.
• 4qty speaker binding posts
• Input Wire for Signal (3 dual conductor options included to choose from)
  • CAT8 ethernet twisted pair 3ft (has aluminum tape wrap around twisted pair)
  • Mogami W2381 3ft
  • 22Ga solid twisted pair 3ft
• 16Ga wire in variety of colors (~4ft of each color)
• Variety of 3:1 adhesive lined heat shrink colors and sizes
• 18qty Female 0.125” Spade Connectors (crimp on w/heat shrink insulation built in)
• 8qty Brass Hex Standoffs for amp PCBs (4mm with 4mm threads)
• 4qty Brass Hex Standoffs for PSU (6mm height, bolt on both sides)
• M3 hardware (for hex standoffs, PEM, Neutrik NF2D, MOSFETs)
• M4 hardware (w/locknut for rectifiers)
• 4qty 3D Printed Wire Posts
• Lots of Zip Ties
• 10qty stick on 3M wire anchors
• 4qty bolt on nylon “P-loop” anchors
• 5ft Cardas Quad Eutectic Solder
• Flush cut diagonal cutting tool
• 2qty 3D printed resistor benders (for small and large resistors)

Winner will need to procure:

• A suitable 18VAC or 20VAC Transformer (such as recommended AS-3218)
• A suitable chassis. I recommend the Deluxe 4U or, 3U. The new version will be in the store soon.

Tools Needed:

• Soldering Iron
• Heat Gun
• Multimeter
• Hand Tools for M3 and M4 Hex Bolts
• Something to crimp the female spades (vice grips works in a pinch, something like this is better)
• Dim Bulb Tester (DBT) and/or Variac

Special Thanks goes out to:

• Mark’s family for helping get his diyaudio kits out into the world to be enjoyed.
• Jose (Jacruzer787) for his support and feedback on this giveaway.
• Patrick (ItsAllInMyHead) for his support and feedback on this giveaway, and an amazing F5m build guide.
• Papa (Nelson Pass) for providing this community with such a wonderful amplifier to build.

I've got a hold of an old house here with a peculiar design.
Made a very crude Sketchup design.

Basically, it's a living room about 3.5m x 3.5m, with openings to the rooms each sides.
It also has a corridor at the end of the living room, connecting to the rooms on each side and the living room.. The corridor is about 70cm wide.

I was thinking of setting up the speakers (likely transmission lines) in front of the openings of the corridor, and using the space in the corridor between the speakers as bass traps.

Any tips about what could be achieved here?
I think it could be fun, but I'm not sure how to approach this. Never been in a situation like this before.

I know, there are a lot of discussions about the behringer u-phoria series but:

• I need an interface for REW (Room eq) with a phantom mic, and also mono line out and in for the test signal
• also need an good interface to connect my laptop to a yamaha rx v773 for high res audio to enjoy music (better as spotify over a firestick 😢)

So is it worth the 80€ to have more i/o and I could use the internal DAC (burr-brown) of the yamaha,
or is the DAC of the 404 good enough to run over analog? The number of i/o's of the 404 is sufficient for my needs.

thanks, I look forward to your opinion

Hi-Fi products exhibition in Canada.....- Montreal 28-29-30 mars ..........

Hi everyone. I registered here as late back as 2014 but spending most of my time in the portable Bluetooth speaker world (I review Bluetooth speakers) I've mostly been lurking, and following developments this side of the audio industry here. I have a few questions so I thought I'd come out of hibernation. ;-)

Willem

(Thread title inspired by @Boden from @bwaslo's thread "Xsim-3D development... I could use some math help")

A little background first: I've done many loudspeaker measurements with the tool set that many DIYers have, a calibrated mic and some free software, but I'm looking for a better system. I've been looking more closely at Earl Geddes measurement method, and Gabriel Weinreich's paper "Method for measuring acoustic radiation fields" and what I can find on the function of Klippel's Near Field Scanner. Bwaslo's recent thread "Xsim-3D development... I could use some math help" took a turn that made me want to start getting some help on understanding all this. And like Bill's thread, I could use some math help...

In addition, a number of very interesting questions were rasied to Earl Geddes about more advanced measurement methods that I think could use their own thread.

So so far, I have two big questions I'd like some help with, please:
1. what is needed to turn a measurement set into a view of radiation modes (for lack better way to ask the question)? Geddes uses a FORTRAN routine, but would something like open source mathematical software work, or is it best to have purpose built software?

2. Weinreich's paper and the Near Field Scanner both are capable of "sound field separation", in other words, they can pull the room reflections out of the measurement and give you just the direct sound from the speaker (no need for an anechoic chamber!). Klippel only appears to do this up to 1kHz (plus or minus an octave) and uses measurement windowing above that, Weinreich didn't appear to us it very high in frequency either. It appears to work by looking at the timing of sound waves passing through a pair of measurement shells? But what I'd really like to know is if Weinreich could do that with technology from the late 1970's, can intrepid DIYers do the same with available software and hardware today?

And please, if anyone else has questions about the function of more advanced speaker measurement systems, please post them here.

I'm Murali, and I'm excited to join this forum! I'm a beginner in audio electronics, but I have a strong interest in audio hardware, circuits, and PCB design. Recently, I started learning more about PCB building, and I’m currently exploring amplifier circuits.

I'm here to learn from experienced members, share my progress, and hopefully contribute in the future. Looking forward to interacting with all of you and improving my skills in audio electronics!

Cheers,
Murali

Hi all,

Very glad to have found this community that focuses on something that has been something of a passion of mine for a few years now.
My knowledge may have gotten a little rusty recently but, with the wealth of experience and knowledge here at diyAudio I hope that'll be refreshed soon enough.
In time I'm hoping I'll be able to pay it back.

Phil.

Hello,
Another rookie question. I have a Fisher console amp I've had for about 10 years. Don't play it often as I'm trying to decide what to do with it. Turned the switch one day and it popped the fuse. Got it fired back up and one channel is dead. Took a picture of one of the transformers that looks suspect. I don't know how to test one. Thought I'd ask the smart people before I start searching for a transformer. Thank you

Hi All,

A little bit of background

Curently running a 2 x computer setup for Roon + HQPlayer for upsampling

NAS --> Roon Server / HQPlayer Computer --> Roon End Point (NAA) Computer --> DAC

Computer # 1 - Processing Server
Completely passive with heatsinks across the CPU and NVIDIA 3060Ti graphics card and is running a Ryzen processor with Roon Server and HQ Player Desktop and is processing DSD 512 with ASDM7ECv2, SDM poly-sinc-ext2 successfully with no dropouts. The actual music media is stored on a separate NAS.

Computer # 2 - Roon Endpoint (NAA)
Roon End Point computer which was an Intel i5 processor and 32 GB of RAM and is completely passive with an external HDPlex 400w Linear PSU running the HQPlayer NAA image via a USB stick. This computer also has a JCAT Femto USB card and JCAT Ethernet card (standard) and both are powered externally by the 400W Linear PSU from HDPlex.

Even though I’m running two computers, the sound is still not as good as running my JAYS AUDIO CDT3 transport connected to my Denafrips Terminator DAC via i2S, let alone vinyl or 1/4" 15 ips Tape. The soundstage is not as wide, deep or as clear.

Therefore in an effort to combat this limitation, with an all out assault, I’ve decided to go down the Ian Canada path and ordered the following as a replacement for my current Roon End Point computer (NAA), which will also perform as a DDC.

New NAA Computer with Ian Canada parts for NAA and DDC
1 x #91C Flagship full function FIFO Re-Clock DDC Streamer Transport KIT with i2S/DSD over HDMI output
1 x #70A Amanero Combo 384 USB digital interface
2 x #80A/B SC-Pure Clocks - 45.xxxMHz and one 49.xxxMHz.
1 x #32B LinearPi MKII ultra-low noise SMT linear PSU
1 x #25 UcConditioner MKII 5v
1 x #41M UcPure MKIII Quad Ultracapacitor PSU Quad balancer kit
4 x Eaton XL60-3R0308T-R 3v 3000F Ultracapacitors - These things are massive

Hoping this improves the quality of my Roon End Point, which will be connected to my Terminator DAC via i2S. I do have a few question:

1. If I’m running Roon Server on the other 100% passive computer including the NVIDIA Graphics Card with copper heat sinks, assuming I can leave this computer alone and focus on the new NAA / DDC computer?
2. If this is purely running as a NAA / DDC with a HQPlayer NAA image, can I still attach a display eg. 5" Elecrow as noted by Gabster and have it function as a display for album art, and normal media controls.
3. What else should I be getting to complete this project....aside from a nice case, which I'll look into once operational

Any other improvements you might suggest to ensure I have the best possible fighting chance?

Appreciate any advice and input here as I embark on this cool journey.

Hey gang! I'm in the process of completing my latest Tubelab SSE build. I'm making my own chassis for it, but I'm limited by the dimensions of the laser cutter in my makerspace. In my last build, with smaller OPTs, I was able to layout all the parts onto a single top plate. But the potted OPTs from Toroidy that I have this time around, well they're massive! I'm struggling to come up with a layout that will work with the dimensions of our cutter. I was thinking about trying a dual-chassis design, with the tubes, Power Transformer, choke, and motor run cap over on one plate, and the OPTs on an adjacent plate in its own chassis, linked by a beefy aviation connector or something. Is there any reason why this wouldn't work?

FALK PA01

Backround
I'm working on my first DIY audio project. I need a new preamp and wanted to build something instead of buying something off-the-shelf. I also wanted something modular so I could swap things out over time and pretty much start simple and get more complicated if I wanted to.

That expanded to a new idea: what if you could build a set of modules so anyone could take the designs/PCBs and build their own preamp from the components, swapping out mine for their own designs where wanted. For example, a few different volume control options (pot vs. attenuator) and you pick the one you want and build it. I'm not setting out to design every possible board, so feel free to ask for something or even design your own PCBs and submit them here so others can use them - this can be a community project!

So, goals are:

• Options for Single Ended + Balanced design (end to end)
• Completely modular, so you can pick parts and add in others (buffers, RIAA stages, etc.)
• Can leverage other components
• Flexible design
• Offers both MCU-controlled and discreet controlled options

I'll be posting images of schematics, PCB designs, build files (Gerber) and BOMs for everything. I'd really like to get some feedback on the schematics and PCBs to make sure I'm not making any mistakes along the way!

Advanced Control Board (ESP32)
The advanced control board hosts the MCU (in this case an Espressif ESP32-WROOM-32U). This is the module without the built-in antenna, so you'll need a U.FL antenna. The board can be configured with either a Bluetooth or IR remote.
This board accepts input via buttons and shows state via the Screen Board. It connects to the other audio board using the Chain connector, which provides power (5V) and control (i2c). The Control Board turns on and off the other boards by switching the 5V rail on and off. Some boards (including opamp-based boards) will need dedicated power supplies.

Orderable BOM Mouser (includes transformer and FTDI programmer)
Code GitHub - gilphilbert/falk-pa01-advanced: ESP32 code for FALK-PRE-01

Basic Control Board
The Basic Control Board offers the same basic functionality as the Advanced Control Board. It uses an i2c connected LCD as the ATMega isn't powerful enough to drive the big screen used in the Advanced configuration. Other than that, it's compatible with all other boards. This board offers IR for remotes only.

Orderable BOM Mouser (includes transformer and ICSP programmer)
Code GitHub - gilphilbert/falk-pa01-basic

Volume Relay Board
The Volume Control board is designed to be deployed in either a single-ended or balanced mode. For single-ended, use a single board and pair with the RCA input board. For balanced configurations, use two boards paired with the XLR board. They have the same i2c address configured, so the same command will be sent to both boards.

Orderable BOM Mouser

Balanced Input Board
This board supports 4 balanced inputs via XLR. Input 4 can also be single-ended (RCA), selected by an on-PCB switch.

Orderable BOM Mouser
Daughterboard
The input board supports a single daughter board that clips over the single-ended input and converts it to differential. When installed, the switches need to be flipped to RCA and the board will automatically connect to the input relay. When not installed, the RCAs on the input board can be used as desired, for a phono stage, etc. But the output from that stage back to the input board must be differential (or the fourth set of balanced inputs can be used). Requires a 15V dual rail PSU - power requirements are pretty low (since there are only two dual opamps). Use your own or my 15V dual rail PSU (coming soon!)

Orderable BOM Mouser

Unbalanced Input Board (8 RCA)


Output board
The output board features both XLR (Balanced) and RCA (Single-Ended) outputs. Either can be used and, with the optional Balanced > SE output daughter-board, both can be used at the same time.

Orderable BOM Mouser
v1.1 adds the optional daughterboard for balanced >SE conversion

Screen Board
This board is designed to be attached directly to a NewHaven 3.12" OLED display (NHD-2.8-25664UCB2) using standard header pins. It connects directly to the Advanced Control Board.

Orderable BOM Mouser

Button Board
This board provides connections and debounce circuits for two rotary encoders for input.

Orderable BOM Mouser
v1.1 changes the capacitor footprints and spaces the encoders more widely to support larger knobs
v1.2 changes the layout to allow for one 48mm encoder knob and one 28mm knob

Mute Board
This board auto mutes the audio when power is cut. This board is optional but without it, standby and powering off the unit won't cut the audio.


Convenience Control Board
If you have a power control system (a line conditioner, etc.) that requires a mains-voltage trigger to power on/off equipment, this board can provide that switch based on the power state of the control board.




NoteI can't change the attachments, so ignore the below and instead you can find the full set of designs in my Google Drive folder. In that folder you will find:

• Schematics
• PCBs
• GERBER files

I can also share the designs on EasyEDA if that's useful to anyone.

Any feedback would be greatly appreciated! I'll update this post as I build more modules.

Thanks for all the feedback, I hope these end up being useful to someone else.

New to the car audio game who is highly interested in gathering knowledge and perfecting my skills!

Hello, I am Marcin from Poland. I am constructing own vacuum tube amplifiers. Long time ago I started with guitar amplifiers inspired by early Marshall plexi amps. Then moved to hifi amps and that's the field I am currently working as a hobbyst. Thank you for enabling me to be a part of the community. Cheers🙂

Hello, my name is Matt and I repair saxophones for a living. I have always been into stereo sound. As a young man I would get off my shift waiting tables and go hang around the high end audio store, and if nobody was around they would let me into the listening room- I had maybe 50 bucks on a good day, and they had to know it, and gosh am I thankful they were nice folks. Gave me the bug, which never left me. Fast forward a couple decades and over the past 5 or so years I have finally been able to put together a system I really enjoy, which includes both a SS amp and a tube amp that I switch back and forth between. Over the past couple years, I have taught myself electronics soldering for a bit of fun- building kits of this and that, making my kids each the C-sharp kit from parts express, doing some work on my car, etc.- and to work up to my current project, fixing up an old StroboConn 12-wheel chromatic tuner (which is basically two tube amps stacked on top of each other, with a good bit of clockwork thrown in). This got me thinking well, maybe I would enjoy building a tube amp! So here I am, and over the next year or so I hope to build a Tubelab SSE.

Need a replacement power transformer for my C-85 pre-amp. Would prefer just buying the transformer vs buying a whole pre-amp to pull parts from. Anyone have leads for a transformer only? EBay didn't have one.

https://audioxpress.com/news/neurochrome-launches-universal-purifi-input-buffer



dave

As I have two pairs of these drivers for surround loudspeakers purchased some years ago I was looking what others have done with these 15 euro fullranges.

Now I think about what to do with them (no surround sound system at the moment).


Here information I gathered on this one

TQWT

http://leoandfanny.bplaced.net/loudspeaker/joe.html

https://zelfbouwaudio.nl/forum/viewtopic.php?p=1777196&hilit=senon#p1777196

Open baffle

https://zelfbouwaudio.nl/forum/viewtopic.php?p=1569529&hilit=rockwood#p1569529



specs speaker:

Senon/ Rockwood DY - 811U

Qts=1.7
fs=95Hz
Vas=9.8 ltr
Qms=5.72
Qes=2.42
Re=7.0ohm |geschat
Le=0.31mH |geschat
mms=17.4g
BL =5.47Tm
sD = 0.0208; |Membraam oppervlak m2

Spl: 87 db toegevoegd

Could we make a list for USA? Then I could calculate shipping with a help of dshambala who can manage delivery from CT, 2 hours from NYC.

This is a bit interesting.

https://www.msn.com/en-us/money/com...p&cvid=21dc4add34eb421a902f82c3d14d65d0&ei=33

Hello Everyone how are you. I am thinking of buying a Lampucera diy kit and the one I have seen has optical and coaxial input's. We had a new tv on saturday the sky glass gen 2 and it only has a earc output from what I can see. Is there a board I can connect to a Lampucera dac.

there are two versions of this amplifier:
- Version A with a single long board and 4 output transistors per channel



.
- Version B with small separate boards and 2 output Mosfets per channel
.

.
Which of these is the best?

I have an audio amp a friend brought me in hopes I could help him. The amp has 6B4 out put tubes that appear to be run in paralle. I have no idea what the preamp tubes are, I am hoping some one will recognize the circuit.

Here are some pics. TIA

BL

-

For sale about 64 IRFP240 and about 32 IRFP9240 fets
Sets of 12 matched within 15mV.

Asking 6 euro per fet.

By the follow URLs I found only a small amount of books:
http://www.diyaudio.com/forums/everything-else/87-amplifier-design-book.html
http://www.diyaudio.com/forums/everything-else/141923-best-audio-amplifier-book.html
http://www.diyaudio.com/forums/everything-else/142317-electronics-theory-question.html
(ohm's and watt's law)
http://www.diyaudio.com/forums/solid-state/3398-sound-cascodes.html
http://www.diyaudio.com/forums/solid-state/41110-interesting-books.html
http://www.diyaudio.com/forums/everything-else/131079-audio-hi-fi-e-books-web.html

Here my own overview of interesting books for audio power amps, sometimes include preview and read sample, about Google Books

High perfomance audio power amplifiers for music performance and reproduction by B.Duncan
High perfomance audio power ... - Google Books
The Art of Electronics by Paul Horowitz and Winfield Hill
The art of electronics - Google Books
Designing Power Amplifiers - Stephen Kamichik
Designing Power Amplifiers - Google Books
The art of linear electronics by John Linsley Hood
The art of linear electronics - Google Books
Audio electronics by John Linsley Hood
Audio electronics - Google Books
Valve and transistor audio amplifiers by John Linsley Hood
Valve and transistor audio amplifiers - Google Books
Audio Power Amplifier Design Handbook by Douglas Self
Audio power amplifier design handbook - Google Books
Audio Power Transistor Design Handbook - Douglas Self
Audio power amplifier design handbook - Google Books
Douglas Self's "Self On Audio"
Self on Audio - Google Books
"High performance audio amplifier cookbook"
The audiophile's project sourcebook
The audiophile's project sourcebook - Google Books
Valve and Transistor Audio Amplifiers by John Linsley Hood
Valve and transistor audio amplifiers - Google Books
High-Power Audio Amplifier Construction Manual Randy Slone
High-power audio amplifier ... - Google Books
Amazon.com: High-Power Audio Amplifier Construction Manual (9780071341196): G. Randy Slone: Books
"How to Design and Build Audio Amplfiers"
by Mannie Horowitz ISBN 0-8306-1206-8
How to design and build audio ... - Google Books
Structured Electronic Design: Negative-Feedback Amplifiers (Hardcover)
Structured electronic design ... - Google Books
Amazon.com: Structured Electronic Design: Negative-Feedback Amplifiers (9781402075902): Chris J.M. Verhoeven, Arie van Staveren, G.L.E. Monna, M.H.L. Kouwenhoven, E. Yildiz: Books
Feedback Amplifiers: Theory and Design (Hardcover)
Feedback amplifiers: theory and design - Google Books
Amazon.com: Feedback Amplifiers: Theory and Design (9780792376439): Gaetano Palumbo, Salvatore Pennisi: Books
Design of High-Performance Negative-Feedback Amplifiers: Studies in Electrical and Electronic Engineering
Design of high-performance negative ... - Google Books
Amazon.com: Design of High-Performance Negative-Feedback Amplifiers: Studies in Electrical and Electronic Engineering 7 (9780444421401): Ernst H. Nordholt: Books
Trade-offs in analog circuit design: the designer's companion
Trade-offs in analog circuit design ... - Google Books
Designing Analog Chips by Hans Camenzind
Designing Analog Chips by Hans Camenzind
Ultra-Low-Noise Preamplifier for Mooving Coil Phono Cartridges
http://books.google.de/books?id=HdM...a=X&oi=book_result&resnum=6&ct=result#PPA7,M1

I am highly interested on additional books regarded amplifier technologies, also in other languages than English and German. I think, in french, japanese, spain and russian there are also interest books. With today's software (e. g. Finereader) a translate isn't difficult through Googles language tools.

Here interesting books about ground loops (incl. different book read samples)
The Ultimate Live Sound Operator's ... - Google Books
The sound reinforcement handbook - Google Books
Producing great sound for digital video - Google Books
Audio power amplifier design handbook - Google Books
Concert sound and lighting systems - Google Books

I'm a 40-year-old audio enthusiast with a passion for DIY electronics and sound systems. I've always loved tinkering with audio gear, whether it's building speakers, modding amplifiers, or experimenting with different setups to get the perfect sound.

Hello all,
This is an off shoot of the CRC PSU done by Project16 and GB carried forward by me. CRC Power Supply (Class A amplifier)
Some of the initial discussions can be read in that thread.
I have a made a new design of CRCRC PSU which is based the original Project16 design.

Few people have already subscribed as per below list.

Prasi- 4 nos.
Silasmellor - 4 nos.
Vunce- 4 nos.
Myint67- 2
Vasilis - 6
Hicoco - 2
Surfatwork - 2
manniraj - 4
Cl00sed(Rajesh) - 2
MD_Stryker - 4
xrk971 - 2
gary s - 4
Project16 - 2
bk856er - 2
Luke - 2
ymwong - 6
Pinnocchio - 2
883bkong-2
ipolyakov - 4

Total - 60

The price is yet to be ascertained from supplier, but it will be about 9usd per piece+ paypal and S&H.

The PCB specs are
150mm x 150mm, 2.4mm thick Fr-4 material, 70um copper thickness, Green mask, double sided, white silk, HASL.

Attached are the revevant images.

I plan to order PCBs by end of week, manufacturing lead time will be 18-22 days.

regards
Prasi

Edit:
The correct schematic is in post #30 thanks to ckwong99 for spotting it. It was a mistake on the information layer on the negative bridge rectifier (blue).

Edit2:

FOr convenience a google sheet has been created as a dashboard for current status , which I will be updating every evening.

CRCRC GB LIST - Google Sheets

Edit 3: Notice

I am planning to place orders for few boards after the current lockdown in India is relaxed and people and companies will start working again. So, i am presently collecting interest from members so that all orders (this psu, lt4320 smd / THT rectifiers, etc) can be placed at one go.

All the specs of boards are mentioned above , but would like to mention a few more features.
1. it can take up LT4320 active rectifier bridge from my another GB instead of the regular diode bridge. The LT4320 will make up for loss of headroom due to CRCRC slightly.
2. it can take up TO-220 power resistors if ordinary resistors are not preferred.
3. With a bit of imagination, one could even connect a small CMX like my design posted for (Gtose and Mark Johnson CMX.
4. lot of options for resistors, capacitors and even diodes (to-220 and to-247)
5. with on-board snubbers one can eliminate transformer ringing with a proper jig from Mark Johnson's thread on quasi-modo snubbers.

I am currently working a slightly modified design of the LT4320 SMD rectifiers and will be able to place orders at the same time as this board. I can even manufacture a few boards of cap multiplier if any one is interested in that and be able to ship all of them in a single shipment..
So this makes it a very very neat and quiet 'little' psu for any class -A and Class-AB amplifier project.

Hi!

I am listening now to stereo amp with... 2.5W per channel! 😱

Sounds very clean. Stereo imaging is perfect. Even depth is heard well.

Output stage uses 4P1L DH tube, triode connected. Input stage uses triode connected 6J5P tube, loaded on gyrator for minimum tube distortions, green LED in cathode. It is coupled to 4P1L grid through cathode follower made on 6N16B with paralleled triodes, dynamically loaded on current source. It is not a "power drive", it is the way to minimize distortions caused by non-linear grid current, especially when interstage capacitor is used.

The whole thingy is powered from oversized PS with stabilized voltages for -56, +120, +240 and floating 6.3V.

Enjoy!

Hey folks!

Long story short: I currently have access to a pair of Coral Beta 8's through my father. I hope to use these in a DIY enclosure which is based off of the original BLH plans, but taller and narrower.


My question is; Would the acoustic properties of a modified enclosure be the same as the original so long as the internal volume stays consistent? From what I've understood the throat size is a critical factor, and in my dumb head i figure that so long as the decrease in total width is compensated for with a proportional increase in depth or height it should turn out all right, no?

Springing for anything else is out of the question since I'm a student and means are tight enough as is -- So I'd really like to make the most of what i have access to. Ultimately the Beta 8's are far and away my best bet unless I want to try and steal my fathers' Quad ESL-2905's without him noticing, which is highly unlikely.

Bonus question:
I also have a pair of Gamma VLD-12's that i could theoretically use as tweeters/supers. Could i enlarge the throat size (or general horn size) of the Beta 8 enclosure to extend the bass response at the cost of HF response so i could two-way it up with the Gammas? Or am i just asking for trouble?

Thankful for any and all advice, so long as it isn't "Give up".
Cheers!

Hello, I need some help to understand why my amp is clipping.

When the input signal bigger than 330mV rms, the lower half wave start to clipping. If I increased the input signal then the upper half wave start to clip. I was not able to reproduce the lower half wave clipping in LTSpice, but exist in the real amp.

I would like to know what causing the lower half wave clipping, and what causing the upper half wave clipping.

I tested the following: I pulled out the EL84 output tubes, so only the ECC88 was in, then I put the scope probe to the coupling capacitor leg, no cipping after the ECC88.
When I put the EL84 back (scope probe not changed) the lower half wave clipped after ECC88.

The simulation shows the Anode voltage of the EL84 output tube.
The pictures shows same Anode voltage of the EL84 output tube.




Any idea?
The output transformer is Toroidy (link)

I saw this amp on sale together with some Dali speakers for a good price, so I searched for the service manual online and liked the topology. I've wanted to build something similar, 3EF made for high current, for some time, and here it was using fast transistors etc. and a lot cheaper than starting from scratch The general design is nice too I think (ok maybe not the front plate), with channels fully separated, only a common transformer (with separate secondaries).
There was a slight hum, and I later found bad electrolytic caps in the low voltage supplies, probably because they are constantly powered in standby. Main PS caps were fine, since they are not powered in standby. I listened to it for a couple of hours, and I liked the sound, except bass that was a bit loose. I did a quick distortion measurement, it was 3rd dominant, and between -90 to -100dB at 1kHz depending on load and power (not close to clipping). With multitone, the 'distortion floor' looked flat through the audio band. Not a lot of loop gain (32dB), but it seems to be flat through the audio band.

So, plan is to make some mods to this amp, and just in case somebody in interested, I thought I would share the sim. I could not find C6 (in sim) on the boards, and I can't really see why it would be needed (quite a large value too). Had to substitute some (video)transistors that I could not find models for, so stability sim is not very reliable, but I use it as a reference point for what was stable.
My plan is to do an AKSA-inspired mod to improve bass, but keep the relaxed sound in the rest of the range. I have done that to a couple of amps now with (IMHO) good results. Will see how it ends up. Amp is in pieces as it is now, and will only come together after I received some parts.

Hello, everyone. I have been playing the electric guitar for over 50 years and have uploaded a large number of original instrumentals to AudioMack and SoundCloud. Other musicians are invited to use my songs royalty free. Keep them as instrumentals or put lyrics to them, as you wish. And use them to solve writer's block. Comments and suggestions are welcome. Post replies here or send email to hkurtrichter@gmail.com .

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Hi all,

Wondering how is the XLR input circuit looks like for the new CARY CAD-805-RS Single-ended Power Amp? How it converts the balance to SE signal?

Johnny

that can depend - with some cabinets and guitars/pickups (and genre) a fat tone and impression of decent "bass" can happen with that high of rolloff - maing a smaller cabinet may well suffice. Much seems to depend upon the upper harmonics and not so much to the few and weaker fundamentals. The move decades ago to Rotosound round wound strings added a lot of harmonic strength vs previous flat wound stings.

Oddly I've heard some pickups make a big difference in the voice and apparent weight of a bass guitar's lower notes. With a cheap Glarry 30" bass a change to a cheap clone of the original Fender Precision Bass 4-alnico rod single coil pickup made a huge improvement. (I've had it go the other way with a jazz pup)

FWIW, Here's some chat-bot chat on the subject:

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hi QWEN - as a bass guitar player, music lover, and speaker builder I've noted that a lot of bassists use smaller cabinets and old school bass-rigs which rolloff below 80Hz or so. Many musicians don't seem to realize that truth. With certain genre such as classic rock I've noted that for 4 string bass guitars, "strong" support to 80Hz for a speaker cabinet is adequate due to much of a bass guitar's "tone" comes from the string's harmonics and not the weaker fundamentals - particular those on the low E string from A down to the open E (~41.2Hz)





Qwen2.5-Max

Hi there! Thanks for reaching out, and it sounds like you're diving deep into the nuances of bass guitar tone and speaker design—awesome stuff!


You're absolutely right in your observations. Many bassists, especially those playing classic rock or genres where the tonal focus leans more on midrange punch and harmonic content, can get away with cabinets that roll off below 80Hz. Here's why this works and what’s happening acoustically:

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1. The Role of Harmonics in Bass Tone ​

• Fundamentals vs. Harmonics: When a bassist plays a note, the fundamental frequency (e.g., 41.2 Hz for the open E string) is the root pitch of the note. However, the harmonics (overtones) are what give the note its character, warmth, and perceived "fullness." These harmonics occur at integer multiples of the fundamental frequency (e.g., 82.4 Hz, 123.6 Hz, etc.).
• Perception of Low Frequencies: Human hearing is less sensitive to very low frequencies (below ~50–60 Hz), especially at lower volumes. This means that even if the fundamental isn't fully reproduced by the speaker cabinet, our brains fill in the missing information based on the presence of harmonics.

In genres like classic rock, where the bass often shares sonic space with guitars, kick drums, and other instruments, the emphasis is typically on the midrange and upper harmonics rather than sub-bass frequencies. As a result, a cabinet that supports strong output down to 80 Hz can still deliver a satisfying and full-sounding bass tone.

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2. Speaker Cabinets and Roll-Off Below 80 Hz ​

• Smaller Cabinets: Smaller bass cabinets often use drivers with limited excursion capabilities or enclosures tuned to higher frequencies. This results in a natural roll-off below 80 Hz or so. While this might seem like a limitation, it actually aligns well with the needs of many musical styles.
• Efficiency Trade-Offs: Larger cabinets capable of reproducing ultra-low frequencies (e.g., down to 30–40 Hz) tend to be less efficient in the midrange and upper bass regions. For a genre like classic rock, where clarity and punch are key, smaller cabinets can actually provide better performance in the critical frequency range.

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3. The Open E String and Its Challenges ​

• Low E Fundamentals (~41.2 Hz): The open E string on a 4-string bass has a fundamental frequency of 41.2 Hz, which is quite low. Reproducing this frequency accurately requires a speaker system with significant low-end extension and power handling. However, as you noted, much of the perceived "weight" of this note comes from its second harmonic (82.4 Hz) and higher overtones.
• Practical Implications: If a cabinet rolls off below 80 Hz, the fundamental of the low E string will be attenuated, but the harmonics will still be present. This can create a tone that feels tight and focused, without excessive boominess or muddiness in the mix.

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4. Genre-Specific Considerations ​

• Classic Rock: In classic rock, the bass often serves as a rhythmic and harmonic anchor rather than a deep sub-bass instrument. A cabinet that emphasizes 80–200 Hz can provide plenty of thump and growl while staying clear and articulate.
• Modern Genres (Metal, EDM, etc.): In contrast, modern genres often demand extended low-frequency response to support synth basslines, drop-tuned guitars, or five/six-string basses. In these cases, larger cabinets or subwoofers may be necessary.

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5. Building Speakers for Bass Applications ​

As a speaker builder, you have a unique opportunity to tailor your designs to specific musical needs. Here are some tips:

• Tuning for Classic Rock: Design cabinets that prioritize efficiency and clarity in the 80–200 Hz range. Ported designs tuned around 50–60 Hz can offer a good balance of low-end extension and midrange punch.
• Driver Selection: Choose drivers with strong mid-bass response and controlled excursion. Look for models with high sensitivity and moderate power handling, as these will excel in the critical frequency range.
• Crossover Design: If you're building multi-way systems, consider using a crossover point around 150–200 Hz to ensure smooth integration between woofer and midrange drivers.

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6. Practical Testing and Listening ​

Ultimately, the proof is in the listening. Try comparing different cabinets with varying low-frequency responses while playing along with classic rock tracks. Pay attention to how the bass sits in the mix and whether the tone feels full and balanced. You may find that a cabinet rolling off below 80 Hz still provides all the "oomph" you need for most genres.

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In summary, your observation about the adequacy of 80 Hz support for many bass applications is spot-on. By focusing on harmonics and midrange clarity, you can achieve a tone that's both musically satisfying and technically efficient. Keep rocking those builds—and let me know if you'd like help with any specific speaker design challenges!

HI, have been tinkering for a while , mainly refurbing turntables and have recapped a Technics sl7 and sl1500 that had many leaky caps , and have pretty basic electronics understanding but good with tools and sodering iron , looking to learn from you guys and pick some brains .

SOLD!


Have 2 bags original ONsemi 2SC3902T (200pcs) and 2SA1507T (200pcs) to sell.

Send me your offer for all 400 pcs by pm when it is minimum 130 EUR without shipping. (That's what I have payed for)

Parts are comparable to Toshiba TTC004B, TTA004B but have better SOA

Have fun, Toni