I have a single Lowther A55 waiting for use but the question is somewhat generic - I've been looking around for inspiration and I see a lot of people have been happy putting a full range driver with whizzer cone into a front loaded horn. So I've been reading up on horn theory, and see how a front loaded horn works with a cone driver. But there's not much written about how a whizzer cone driver works in such a horn.
The popular tractrix profile, and other similar profiles usually require the horn to have quite some length in order to reproduce lower frequencies and this looks like a bad starting point to me for a whizzer cone as the high frequencies will be radiated into the walls of the throat and bounce around from there. Or the throat simply cuts off the higher frequencies altogether. I can see why some folk just cut off the whizzer cones and add a separate tweeter.
So it seems to me that only a shallow horn is practical if the whizzer cone h.f. sound is to be preserved. Then it's down to conical profiles for the most part, or oblate spheroid for better loading of the main cone.

Anybody looking into this ??

I'm looking for crossover schematic of Tekton DI for my summer project.

What I know so far.

- The size of cabinet.
- The model of tweeters .(SB29RDCN-COOO-4)
- The model of midrange (eminence beta-6a )
- The schematic of tweeters/mids
All attached here at post

What I don't know

- 2X Midrange and 2X Subwoofer crossover schematic.
- Eminence subwoofer model number.

I hope you can help me to complete the puzzle.

In my mind, DIY Audio as we know it today, started when Nelson Pass published in Feb 1977 Audio Magazine "Construct A Class A Amplifier" As far as I know, this the first DIY project where the builder had to get more involved in the design. There was no kit, save for maybe a PCB. With Dynaco, Heathkit. etc, there were no design choices, just follow the instructions.

https://www.passdiy.com/project/amplifiers/construct-a-class-a-amplifier

So what is with this Holy Grail of DIY Audio?

The amplifier you see in the article in Audio Magazine, is in my possession. I do not mean one like the amplifier you see in article, the exact same amplifier they took the photos for the article in Audio, is in my attic.

I have owned it since about 1986. Around 1993 I called up Pass Labs. I talked to Nelson Pass, asked him about the amplifier. He said there were 4 or 5 people in the Threshold shop that made their own amplifier. He shared with me a couple details that confirm my amplifier and the one in the article are in fact the same.

This all brings me to the point of this thread. What can I do with this amplifier? This seems to me to be a touchstone to the DIY hobby. Being that it is Pass's first published design, (that I am aware of) this is of historical significance among the DIY Audio Community. It belongs in the DIY Audio Hall Of Fame.

I am looking for a new home for this bad boy. I am happy to donate it to any club or organization or somebody that is has an interest in it. Anybody got any ideas?

Hello all,

First of all, excuse me and I know the question is a bit wide and there is no such measurement as 'sound quality'. However I would like widen my knowledge about drivers that combile high spl output, good specs and are considered to be top quality.

Sold 🙂

For sale is a complete working Zen v4 amp.

I am using Jim’s Audio PCB boards. All of my speakers need a more powerful amp (and I built 2), so time for this project to have a new home. The case is pieced together 4U parts from this site’s store since I already had some previous 4U parts. The back is vinyl wrapped.

New lower price of $400 and now including a set of blank F4 boards, full set of IRFP transistors for it, the original blank Honey Badger boards and the negative side of the blank power supply boards in case you want to put something else in this case.

If you’re in the Detroit area you can hear it, otherwise I’ll ship it. If you’re committed to purchasing it, we can FaceTime as proof of operation.

$650 $400 plus shipping.

Hi!
I'd like to repair the filter of my front right MA BX2. I have a 5.0 system with MA Bronze, coupled to Denon 2113. The tweeter from that BX2 speaker is inaudible for some 2 weeks. I took it out and connected it directly to speaker cable, and it sounded ok, no distorsion. So there'something else inside the speak affected, probably the filter, or maybe something else too.
There's no one in my town who whould repair the speaker, and I dont want to send it far away to a specialised audio shop.

I would rather try to repair it myself, but I've never done something similar. Can you help me? The speaker was bought in feb. 2013.

Thank you.

This was an eye opener.....switched on M2 power amp clone, letting warm up a minute and noticed it had shut it self off. Noticed if Ioved cord, would come back on, then off again.

Pulled power cord out, took top off and started looking around shurter wiring. Tried to pull out fuse tray, and it was stuck. Finally getting it out, looked like solder melted out of one end of fuse, which broke off leaving one cap end of fuse stuck in drawer, which had obviously over heated a time or two!

Works well. Comes with DIRAC already pre-loaded.

The screen works fine. Seems like the phone catches the display scanning. I can take more pictures if desired.

US$500 + shipping CONUS

Hello to all,
I have develop very recently this PCB which use 5 LM3886 they can be installed in the PCB all in gainclone/parallel,fully independent channel's or mixed
configuration, and I want to develop a simetric regulator which can power this, so in terms of amps my target is 20A.
About the circuit for the regulator I am thinking of using power op amps as current source biasing some zeners which will set
the voltage on the output, after the zeners I will use a driver and then two devices in parallel for the output section, I am thinking
of using TIP35/36 but would like to ear some suggestions.
Regarding output overcurrent I am thinking of standart VI limiter but I would like to add also a protection, for creating a safe operation area, this by trip the
circuit if the differential voltage between in/out be greater than 7 volts this for temperature don't rise to fast, but this might bring some problems, for
now I would like to if operating an LM3886 and then remove one side of the supply does it burn/short or no problem of removing one side of the supply?
I hope this resonate with more people as this regulator would also work for any amplifier, after I develop this regulator,I will make it available alongside
with my other modules like this one, you can check it here:
https://www.ebay.de/usr/rocksandsound
Regards

AS-0518 - 50VA 18V Toroidal Transformer​

https://www.antekinc.com/as-0518-50va-18v-transformer/
$20 shipped in CONUS.
New-in-box.
Stock Photo:

Hi Guys,

Just seen a recent press release on the new Hypex Fusion plate amps. Look like game changers for active speaker technology. I can't wait to try these babies out. Press release here:

Hypex Electronics Introduces New NCAS500MP Active Speaker Amplifier Module

Help needed identifying blown capacitor
C29

I have a pair of Mission 701s where the plastic front baffle vibrates against the wooden cabinet because the glue has failed. Apparently this is a common problem but I cannot find a good fix.

Any ideas?

If nobody can think of a better plan I'm going to try using an excessive amount of PVA over 4 days.

(1) Remove the woofer.
(2) Run a healthy bead of PVA along a long side of the baffle on the inside.
(3) Leave the cabinet face down (at a slight angle) to dry overnight.
(4) Repeat the procedure on the other 3 sides.

Will that work?

Up for grabs to our established members are my NT25 tweeters , ferrofluid replaced and working perfectly.

I don’t have the mesh dome covers

I have quite a few other tweeters available too , I will list them if they’re wanted.

NT25’s are £75 + p&p ( I’m UK based )

I have a pair of Carnhill Transformers toroidals for sale. Although not "new", they are unused.
Exact specification as confirmed by a recent email to Carnhill is -

Input 230v 50/60Hz across Blue & Brown, there is a single shot thermal fitted in the blue lead, which 103c rated 3A
Output 12v across Black & Red at 6.25A DC (open circuit volts is 12.96v no load)

These are excellent quality transformers with a potted centre to lower physical noise. Fixing is via 2x M5 threaded bushes.
They are quite substantial at 100mm x 50mm

I think 29.50 including postage within the UK is fair. Can knock a couple of quid off if you want both.
Happy to post internationally at extra cost.

Per a theory written in 1960 by Benjamin Bauer, a 2-channel stereo system is flawed by a compromise as each ear hears both speakers (crosstalk). I have been intrigued by this for over 40 years since purchasing the Sound Concepts IR2100 in 1982 (which I still have). This thread will concentrate on older analog solutions such as the Hughes AK-100, SRS PRO 220, Behringer EX-1, and others. Although an electronic solution is not without its own issues, using a stereo imaging processor can bring some enjoyment to music. At this retirement stage of my life, I prefer things to be simple and comfortable. I find having an external processor to be preferable to the acoustic solution of having to have a mattress or a 4x8 sheet of plywood attached to my nose and cones or baffles on my ears. Please feel free to jump in with your thoughts, comments, likes, and questions.

Does anyone know what the original prices were for the Nakamichi PA300ll amps from the 80s?

Need to make (or buy, unlikely) speakers on front wall. Concerns are oddball effects, isolation from wall material, getting drivers aligned with sweet spot when driver height will be minimum of 150 cm / 5 feet (angle down and in a fraction? Thoughts so far:

1. Will run with sub

2. Make thin

3. Surround by acoustic foam or something else up to level of baffle

4. Designs considered (without much research) include spiral horn (Cornu) and https://www.diyaudio.com/community/threads/tangband-3-inch-honeycomb-cone-w3-1797s-hbw-08.409698/

5. Driver size: Was ready to build Pluvia 7 HD floor standers, but I mocked up a couple of designs, which I always knock over - not enough floor space. Have no issue with driver size, but 3" I made already could do with more ooommph in the room. Those are HiVi B3N, so perhaps some other 3" might do, but I could go up to 5" or 6" without any concern. [If the layout on the other side of the wall were different, I'd be looking at putting drivers in the wall].

6. If wall mount is too much compromise, I can go with fairly compact bookshelf (I'm tight on space, with SO's home theatre unit taking up space). GR-Research suggested https://gr-research.com/product/lgk-2-0-pair/ but reviews mixed.

7. I could mount speakers on shelf or extending wall mounts.

8. I could use floor stand speakers upside down, spaced about 1 ft / 30 cm from wall

Thanks for any suggestions, considerations, sympathy. I'm disappointed that a floor stand set really won't work given narrow, fairly crowded available floor space and the conflict between home theatre use by SO and my desire for crisp, clear, delicate audio without video.

Let's start here this thread, it will be interesting to look to different measurements and to find right way to read them.
Another example to look is two different interconnect RCA-RCA cables. Don't look at greater rise of cab1_delta_phase, it is zoomed on Y axis. Big difference in waveform between original record and 1 or 2 cable is in loopback WASAPI recording and DAC>ADC recordnig. Interesting to know what is wrong with comparing delta phase between different recordings. Perhaps we see a problem in my crap ADC, but anyway anoter differences are seen clearly. I don't want to name this two cables, if you interested, ask in PM. It is not about expensive audio gear. Just about difference.

good morning everyone. I recently purchased the item in question. I would like to know if the dsp input can handle a preamplifier with high gain such as the topping pre 90, or I risk doing damage. the dac has a fixed output of 5 volts.
with the high gain of the topping I could get to 12/13 volts I think. I would not want to do damage and regret it bitterly. Thanks.

Do i need to worry about baffel step correction if i measure all my drivers in the finished speaker cabinet or will that measurement already account for it? Thanks! Travis

Dear All,

I am a Home Theater Enthusiast from India... Now briefly located in Germany.

I joined this community to explore the option of building the subwoofer with OEM subwoofer drivers.

I have a dedicated HT room in India with the size of 13.5 Ft Width X 21 Ft Length X 10 Ft Height.

My existing gears are LCR are M&K S150 and PB2000 Subwoofers (2) and Rythmik FVX 15 (1)..

Now, thinking of replacing all the subwoofers with identical ones through DIY

Thanks for helping me out.

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!

Hello,
I just started working on this project after putting it off for a few years. The idea is: Portable, battery powered, tube shaped, stereo, two way speaker with built in subwoofer, that you can carry with a shoulder strap. The sub will be Tang Band W5-1138SMF, but the rest of the drivers Im not sure. Even after hours of searching I wasnt able to find any affordable miniature two way with good reputation that also has both drivers easily buyable. Currently my only idea is to use Helium (Dayton ND91-4 and Dayton ND16FA-6) but Im worried that it wont be loud enough... or is that going to be a universal problem with small woofers?

All tips and insight would be much appreciated.

Hi

I am planning to assemble a 6 Channel amp with an active crossover , each amp driving highs, mids and low.

Amps that I have selected is apex ax11 for mids , ax14 for lows and lm3866 amp for highs.

Planning to house all the amp boards in one chassis with 2 toroidal transformers . 1 dedicated for ax14 and the other one for ax11 and lm3866 . I have not yet decided on the psu for these amps. I have gone through many threads where Mile suggests using psu10r and psu15. Please can some one help on this?

Much appreciated

Hi!

Been looking a bit into building a high efficiency two-way with a 1st order filter. In other words, as simple as possible.
Are there any good HE drivers out there that works well with a 1st order filter?
I see Zu Audio are doing it with a 10" wideband/full-range.

Maybe a Dayton PM220 wideband woofer with a Dayton AMTPRO-4 or something?

Any suggestions? 🙂

Working as they should

The very fine fabric mesh is missing from one .

£80+ p&p

* Found one *

Looking for one in good condition. Ship to Vancouver BC, or local exchange.

Thanks!
Joe

Greetings to everyone,
I wanted to make an amplifier with LM4702, which has been in my drawer for 15 years. Previously I made 3 separate LM4702 amplifiers and I liked them too much. However, I gave some of them to my friends and I don't know where some are.
I also had Alfet Lateral ALF08NP MOSFETs waiting for at least 10 years in the same drawer. So I guessed that the two would be a beautiful duo.
Since I know that a buffered chipamp will give better SNR-THD performance according to my previous experience. I designed the circuit as buffered.
PCB design was quite simple, as Alfet MOSFET is P and N channel is in the same case.
I wanted to try the circuit without the buffer in the first run.
I simply installed it and assembled it on a single heatsink. Bias trimpots were approximately at mid position, while approximately 300ma per channel was formed. Then I slowly adjusted to 125mA/channel. When the MOSFETs heat up to about 40 degrees (about 10 minutes), I saw that the biases remained constant. And I measured the output noise, inpus were shorted: I read 30uv (20mhz bandwidth) noise in my Oslioscope.
Then I went to the listening test. Connected my Arylic HD-DAC (opamps replaced with OPA1656) to my new amplifier and I have been listening to Wharfedale Diamond 9.6 speakers for hours.
I have to say clearly that although it is not buffered for now, the amplifier's performance surprised me again. I must say that it is a very clean noiseless and distortion -free amplifier. Since I have listened to plenty of Class D amplifier lately, the clarity of the device is quite impressed me too much.
Although both LM4702 and lateral MOSFETs are no longer produced, I would recommend it to anyone who has the opportunity.

Lot of Russian PIO and Polystyrerne Caps in Australia

K75-10 PIO 1.5uF x 4 pieces

K71-7 Polystyrene 150nF 1% x 12 pieces

K71-7 Polystyrne 10nF 1% x 4 pieces

K71-7 Polystyrene 96.8nF 2% x 4 pieces

K71-7 Polystyrene 15nF 2% x 4 pieces

$50 AUD for the lot.

R-Core transformers x 2 pieces
2 x 9v x 1.66 A
windings 240v or 115v

$50 AUD for 2 pieces

I've got an ARC LS3 preamp paired with a P5Pro Dartzeel 108B clone power amp. It is an amazing combo. I bought the Cary SLP90 clone tube preamp (as per Hifi Zone's recommendation on Youtube) with the Dartzeel.

Can someone knowledgeable in these things explain why this 30 yo ARC preamp performs so well and dominates this tube amp which is famous for 3D soundstage?

Furthermore, how hard would it be to overhaul the ARC LS3? I've been quoted silly prices. Can a newbie do it himself?

Lastly, are there any sub $1k preamps that perform like an ARC line stage? Chifi clone or otherwise? It may not be economical to recap the LS3 and I need a plan B...

Many thanks!

Dayton Audio 4” x 2 and CW-2194 x 4 $180 AUD for the lot​

Delivery to most Australian cities would be around $25- $30

Dayton Audio 4” Reference Series x 2 Pieces​

New unused in boxes

RS100-8

4” Aluminium Cone – Full Range

Woofer/Midrange Speaker Driver - 6.5 Inch CW-2194 x 4 Pieces​

New unused in boxes

Frequency Response - 44.0Hz-7.0kHz

Resonant Frequency - 49.5 Hz

Sensitivity (SPL@1W, 1m) - 89.0 dB

Recommended Speaker Box Volume - 19.0 l

RMS Power Rating - 60.0 W

Nominal Impedance - 8.0 Ω

Side-to-Side Diameter - 178.0 mm

Mounting Hole Diameter - 168.0 mm

Cutout Diameter - 145.0 mm


Insert Depth - 7.0 mm

Driver Material - Coated Paper

Hi folks! Introducing myself after a lonnng time of cruising the forums and searching through various designs to decide which direction I'm going to take my project. Almost ready to make sawdust, and very excited to build my first DIY system, which will be used for outdoor events in BC, Canada.

Thanks for the endless wisdom throughout these forums, it's much appreciated!

Hello guys.
I have an Ashdown MAG300 EVO ii bass amp on my workbench. It was stacked together with other music gear in a small storage room - not the best idea. I got it to work now but it does not sound as it should. Cranked up all the way, it does not get to 300W. And I had it once before so I have an idea about how it should sound.
I got the service manual for the ASHDOWN ELECTRIC BLUE MAG which is similar but not the same.
For example: The compressor is missing in the schematics, the Electric Blue has a few different op-amps than the MAG300, also a different IC numbering, etc.
Any idea where to find the correct schematics?

I'm curious about your thoughts.
When designing a speaker network, what do you think about using XSim or VituixCAD compared to using AI assistance?
XSim and VituixCAD are excellent for precise simulation, while AI can suggest design directions, ideas, and optimizations.

Selling this nice pair of 15cm horns made for 1" drivers. These were offered as 'you finish' option, where I purchased the cut horns and did final finishing and sanding. Finished with Rubio 2C wax. They sound fantastic, but I ended up using a different horn to cross over a bit lower. You can read more here (these are variant 007).

SOLD for ask

$200 USD + shipping

Shipping: $10 USD for US address; actual cost for international.

I'm fairly new to the Hi-fi audio scene but I find it quite interesting. I recently got my hands on a pair of vintage floor speakers and I started to dig around for information to see what kind of parts I could use to fix it since some of the speakers on it are broken. I still don't know much about all of this stuff so now I found myself here looking to learn new things. I don't want to disclose any personal information since I take privacy quite serious so I hope you understand.
Bye 👋

I just recently got my hands on a pair of Onkyo SC-670 floor speakers. I got them for free since the woofer and the midrange speakers are broken. I've looked at a few replacement speaker for the woofers and midrange speakers but I'm not sure if they're the right ones for this enclosure. For the woofers I've chosen the Dayton Audio RS-225 4 Ohm and for the mid range I've chosen the Dayton Audio CF-120 4 Ohm. The tweeters still look fine to me so I don't think I have to replace them. I haven't ordered them yet since I'm not sure if they would be the right replacement for the original speakers since I don't really know much about all of this. I've provided some pictures of the original speakers below.

Full Gabster TD-1 kit: PCBs, all parts according to BOM and an original TDA1541A chip.

It is a 100% complete BOM—Gabster provides a Shared Project access code that you type into Mouser, and all the parts get added to the basket. That is how I bought the parts. Everything is packed safely and securely as Mouser delivers it. The PCBs are fresh; I have not soldered anything yet.

Cost 175 EUR in total, plus shipment.

This discrete opamp can work in 150V or +/-75V.
The output works in Class A biased 20mA.
The distortion is very low.
The transistors used can all be found at Mouser.

Hello

I have seen these banana chassis plugs which are flush mounted, but where can you buy these?

Hello all, I am Lonk and highly interested in diy products, looking forward to learn more here.

I like to repair old and Vintage HiFi components.
I have some experience repairing portable radios, amplifiers, and record players from the 1960s onwards. I'm particularly fond of old Braun devices. I particularly like the minimalist design. I also love Dual record players and have already restored a Dual 1219. I also love Japanese models, so a few Technics record players are a great addition to my collection. A few radio flip clocks from Sony and Nordmende provide the right ambiance.
Regards Tim

I cloned the HECD-019A servo board for the tested and working Philips CDM12.1 mechanics.
Now I find myself with a problem.
I had to remove the P87C58 micro controller from the original board because the LQFP44 version is not for sale, I was able to find the PLCC44 version chip that I mounted on the new PCB but it does not work and therefore to make the prototype board work I had to remove it from the original board .
Now a doubt arises, does anyone know if this Philips controller, the P87C58 has a part of memory and therefore must be programmed?
Thanks for your help!

Hello all,
My name is Christian, I am from the US, attending school in Italy. Currently working on installing a digital organ in the chapel of my school...I have been learning about the intricacies of audio systems for a couple years now, and I am mainly interested in audio systems for digital organs, especially with regards to bass (most organs can go down to 32hz, some 16, and very few 8), which is difficult with organs because they have to be able to sustain those frequencies at ~100db pretty much indefinitely.

Read plenty of threads, hoping to learn a lot more from this community!

Hi all. I've recently inherited a pair of JBl 2231a woofers, in need of refoaming, plus 2420 horn drivers, 2312 horns and 2405 slot tweeters. Good for 4333 build, or something close. Id like to build cabinets that get the horns to seated ear height without needing stands, for one thing, possibly positioning the horns on top of the cabinets, bracketed somehow.

Anyhow, my questions really are around crossovers. I'd like to follow Nelson P's design, simplified to exclude l,pads. I see there is a seller on ebay that sells PCBs for a version of this, that features a charge coupling circuit.

Curious if anyone has heard either of these operational... how do they sound?

Also looking for general comment.. I am thinking on First Watt SIT5 to drive these... enough power? I have never had anything to do with JBls before... please excuse my ignorance. Also have MC275 mk6, FirstWatt VFet amps, and a bryston kicking about as alternatives. But really hoping for an expansive, holographic soundstage with the SIT5 for electronic music... not necessarily loud, just lots at low volume. Thanks for any advice here..

A new project: a parallel 4x 6V6 with triode, pentode, and UL switch. Plus, adjustable global negative feedback from 0 to 9db. back to the cathode of driver tube.

Each 6v6 will be individually cathode biased and have its own coupling cap from the driver tube.

OPT will be a 1.2K. Edcor, Sowter, Lundhall or equivalent.

Power supply... no idea. Just a low noise one.

I am trying to figure out driver tube. Pentode, Triode? has to have enough gain for 9db of feedback plus decent input sensitivity and be able to drive a 100K load and the input capacitance of 4 6V6's. Thoughts are a EL84 in pentode mode. 4-8K resistive load. 150v screen, 300v V+, 150v plate, 37mA plate current.

Thoughts? Or should I go with a triode driver?

probably 6W triode, 16W UL, 20W Pentode .... maybe. lol.

All of this is still in very early design stages. But I am pretty fixed on using the parallel 6V6s.

Thank you sooo much!

I have a couple of hundred to match.But how close should they be matched?
They are for discrete headphone and amblifier,

Hello,
I have a question about the wiring of the silk TVC, when used with Bal and RCA outputs as shown here: The type is STA 522A.


What does this switch on the bottom actually accomplish? It seems to reconfigure the grounding scheme when in mute.



It seems that both in position XLR and RCA, contact 1 or 4, respectively connects to secondary 1, which mutes the circuit. Why use a switch here?
The only thing that the switch seems to accomplish is disconnect pin 1 (shield) from the XLR output when set to RCA.

Why is this shown as it is and not made simpler by only disconnecting pin 1 with a spts switch?

Thanks for any pointers.
Florian

To cite my favorite Audio Designer: "Audio design is perfectly mindless fun..."



Didn't intend to make this one; already made Babelfish F8, with few twists (just to justify Babelfish prefix), but that one destined to sit in folder

Some time ago, did found one interesting patent, sharing some basic virtues with Papa's F8, but nothing more interesting

As always, can't remember where tf I saved that pdf, couldn't find it, so few days ago tried to recollect my faint memory what was in .... and while I was thinking, had a napkin handy so I drew some sketches

Anyhow, everyone around (and his cat) is knowing basic principle of Papa's F8; few main virtues ( not both of these being in mentioned patent, feedback approach was in case) are single JFet in input stage, feedback loop containing JFet Rsource ( we know that already from F5 and few later ones) so that allowing that feedback loop is arranged as low impedance, so we can have majority of current feedback merits

now, F8 simplified

Consisted of two stages:

• first one being common source P Jfet,
• second one being (also) common source Semisouth enhanced mode Mosfet , without source degeneration; loaded with Mu Follower stage made of plain vanilla IRFP N Mos

OS Iq set in Mu stage ( optothingie), while input JFet drain resistor being trimpot - allowing setting of output DC Offset; as always - Papa's careful routine is selected Idss of input JFet, so he know what resulting drain resistance is, thus OLG, thus resulting THD SPectra of entire amp

Ha - go clone it, if you can

///////////////////////////////////////////////////////

Edit on 16.08.2022. - final tests and schm values are in post #44, https://www.diyaudio.com/community/threads/scryer-or-how-f8-met-mighty-sissysit.388550/post-7098113

I can see that the DIY DACs has come to life, but I don't see any progress around the output-analog stage. Always the same story with passive conversion or op.amps. In contrast, here is a slightly different solution, the input lamp receives the signal at the cathode and amplifies it and sends it further to the white cathode follower which gives an output with very low resistance .Russian 6S4P with cathode resistor correction can be used instead of 6HM5. Circuit has been tested for now with the current dac PCM1702 which outputs +/- 1.2mA (similar to AD1862) , it will soon be tested with +/- 3.2mA, in fact three PCM1702 in parallel. The power supply for the tubes was performed with a serial low-noise regulator for 260V, the circuit was modified with better reference and taken from ARC LS25MKII. All other important regulators in the DAC itself are shunt type from Mr. Walt Jung with low-noise op.amps and low-noise references. Special attention in the DAC is paid to power supplies and regulators which is really heard in the final sound.
I am now working on a new DAC with a TDA1547 that will also have tubes in the output stage section.

As the Title suggests, I'm looking for a replacement SMPS for a Linn Classik Movie Di.

It looks like this and the only references on the board I can find are 'DESIGN: IW, AW 08/02/02' and 'PCB254/L4' : -

Every now and then I must go and look at this F7 magic thing. I mean, mouser etc. must hate this amp it has so few part! I think this is just plain incredible! Wish I could give an ear to it...

I have a Marshall JCM 900 100W tube amp head from 1990 that likely has an issue in its Reverb Drive solid state circuit.

JCM 900 Preamp Schematic from 1990
/\ The schematic of the JCM 900 preamp especially the "reverb drive" section referred to here.


Troubleshooting Progress
While the amp is on and feeding it a 1khz sine wave, an oscope successfully sees the sine wave up to and exiting the V2a preamp tube and can also be seen after the reverb section of the circuit following the dry path.
However, the sine signal is lost below the R23 resistor at the start of the reverb circuit (totally fine above it). Above it is a 400mv peak/peak sine wave. I would expect to see at least a 200mv sine wave below R23.

1. While the amp is off/caps discharged, in circuit continuity and ohm checks using a DMM on every component in the reverb circuit pass/expected (cannot test the caps but none beep with continuity which is assumed good).
2. While the amp is on, measuring DC below R23, the DMM is registering about -300mv.
3. While the amp is on, measuring DC right of R28, left of R26, above C17, left of R27, right of R26 all measure roughly -14.25V.

This leads me to assume that "maybe" either R23 or C16 have issues and should be replaced, but since I am not a guitar amp tech guru, before I start desoldering components and adding even more variables/fail points to this issue, I am seeking some understanding and suggestions.

Questions
❔ Should I only desolder components, test them out of circuit and then get them back in as the only option to pursue?
❔ Can/should I see if R23 is the issue by temporarily jumpering another resistor of same/lower value on top of it in parallel?
❔ Can/should I see if C16 is the issue by temporarily jumpering another capacitor of same/lower value on top of it in parallel?
❔ Can/should I do either of the above by snipping one or both ends of the resistor or capacitor and then jumpering or "top soldering" the left over leads with new components and avoid temporarily having to disassemble the preamp board to under solder them?
❔ Is there a way to replicate this issue with a simulation? See my attempt at an LTSpice rendition of this part of the circuit below.
❔ Is it correct that if the reverb drive circuit was working I should be able to see a > 50mv sine wave through its components on a scope but doing so with DC coupling on the scope since the op amps have 12-15VDC on all of those lines?
❔ What affect does having the reverb tank being connected or not play into any values I would read?
❔ Would acquiring a newer/digital scope provide such a difference that I should seek that first?


Additional Info


Above is an overview of the LTSpice I attempted to create to provide a simulation of this circuit.
The reverb tank is not an exact replica as it has a much higher input impedance, the reverb pot is fixed R, and I took liberty excluding the channel switching IC7 M5201 and replacing that with a single TL701 (see the actual real link schematic above).
With this simulation, I achieve the expected results below and above R23 and above R20 in the dry area.
While the simulation does see -12V in the op amp areas of the drive circuit, it produces a very small and very distorted ac result which leads me to assume the simulation isn't great.
Thanks to Adrian Immler's post "spice reverb simulation?? This is now possible!" for providing a LTspice of a similar reverb tank.

For extensive additional background leading up to this point, please see this post:
Marshall JCM 900 Reverb Issues
I am aware that it is not ideal and borderline/crosses forum rules about not posting two threads about the same topic; however, when I posted to the valve/tube area I did so since a similar reverb thread was in the solid state area and I have a tube amp and other research implied that one of the more common faults with reverb were related to pre amp tubes, so made the assumption that group was appropriate and now see that forum is more specific to hi fi tube amps.

Love my Sonic frontiers sfl2 preamplifier in stock form apart from a recent replacement of all electrolytic capacitors. I would really like to replace the original 3uf multi caps with Mundorf supreme silver gold oil's but due to size constraints only a 2.2uf will fit. The only over cap I have in mind is a v-cap odam 3uf. Any advice from someone with experience living with this unit and trying these and other caps would be fantastic. Thanks in advance

SB Acoustics Satori MR13TX-4 5" Textreme Midrange​

MAY 12, 2024

I this post I test the SB Acoustics Satori MR13TX-4 5" Textreme Midrange. This is midrange only version (MR) of the Mid-woofer (MW). This is a new product for 2024 and Mark from SB was kind enough to send me a pre-production sample by request. I have been looking for a good all-around 5" midrange for a variety of projects which I will get into at later blog posts. But for this blog post I want to focus on the the raw test data.

Features

• Advanced TeXtreme® cone
• Inverted soft low damping rubber surround
  • The mid-woofer version has a non-inverted surround
• Extended copper sleeve on pole piece

Manufacturer's Published Specification Sheet click HERE.
The most interesting feature of this driver is the textreme diaphragm. I was curious to see just how high the breakup region is which should be well past the typical surround breakup.
Besides the diaphragm, how does the motor perform in terms of distortion? Let's find out!
Test Setup
I decided to test the MR13TX-4 on my 90cm x 90cm IEC test baffle which in addition has a 8.6L sealed rear chamber measuring 13cm deep x 24cm wide x 24cm tall. I first measured the driver using a 30cm mic distance gated to 7cm where the first room reflection occurs. I then measured using a 5cm mic distance and spliced this ungated measurement in at 575Hz for the low frequency portion of the measurement. I applied 1/24dB octave smoothing for above 275Hz and 1/3 octave smoothing for below 275Hz. My measurement mic is an ACO Pacific 5012 running into a Scarlet Solo Mic Preamp.
Measurements
Let's start by looking at the manufacturer's published frequency response. High level we see an average sensitivity of 90dB through the midrange along with a breakup mode at 5.6kHz. The driver starts to become directional starting at 4kHz.

Showing the same zoomed in...

Below is the MR13TX-4 frequency response (red) with the impedance (green) overlay for reference. My measurements show a very linear response right up to breakup at 5.7kHz.

I then extended the same measurement out to 50kHz. It's interesting to note that we see output all the way up to 22kHz. This means two things...that the diaphragm is likely not breaking up and what we are seeing is simply surround breakup effecting the response, and secondly, that the motor has very low inductance. We can see this in the impedance sweep where there is very little inductive rise into the upper treble. Very interesting!

Moving the mic back from 30cm to 100cm to conduct off-axis is shown below. I measured at 0,15, & 30 off-axis. (SB measured at 15, 45, and 60). Below 500Hz I spliced in the ungated response of the same measurement. At the 1m mic position there is a slight bump in the response centered around 250Hz which is likely the result of the 90cm x 90cm test baffle.

With my results, directivity starts to narrow at 5kHz which is a little higher up than SB's off-axis results at 4kHz. So my results are actually a little better than published. This means that you can push your crossover point just a little higher if needed. Side note... This almost is a candidate for a wide band full range driver and appears to only need a super tweeter coming in at perhaps 8kHz?
Impedance
Looking at the impedance mounted in the 8.6L enclosure is shown below. This raises the FS from the factory 44Hz to 76Hz.

Time Domain ​

General comment on Time Domain
The time domain aspect shows the midrange driver's behavior after the signal has ended. The CSD plot looks at the behavoir in terms of time. We can see below that the 200Hz region takes around 3ms to fully die down below -25dB. The burst decay shows how many cycles are required for the signal to die down, which is a more relevant metric in terms of audibility. For example, the 200Hz region shows no issues in the Burst Decay, since 3ms is only a fraction of one cycle at the 200Hz frequency.
Another way of examining this result is to look at the 1kHz region on the CSD. We see that things die down quicker than 0.80ms for this frequency region. Since 1kHz takes 1ms to complete a full cycle, we can conclude that the woofer is able to die down within the time it takes for the woofer to complete one cycle.
Below is the CSD waterfall plot showing excellent behavior across it's usable bandwidth.

The burst decay is shown below, again an excellent result.

Distortion
I started with harmonic distortion placing the mic at 5cm from the diaphragm. The driver required 1.5V to produce 85dB at 1m. Distortion is below 0.10% with the exception of the resonant peak at 4.7kHz. Distortion is still very low even above this region. If the peak was EQ'd out then the distortion would in this region would also disappear.
Increasing the test SPL to 95dB requires 4.60V and we see a slight rise in H2 for the upper midrange. Otherwise H3 and H4 remain very low. (below 0.10%)

Intermodulation Distortion
I then produced a 12 band per octave test signal ranging from 200Hz to 20kHz which required 0.80V to produce the 85dB at 1m test signal. Generally we see around 65dB of dynamic range with surprising clarity in the upper treble as well. Again, if the peak at 4.7kHz is notched out with an EQ, we would see a very good result indeed.

Increasing the test SPL to 95dB required 2.73V and reduces dynamic range to a correlated amount of 55dB. Generally we don't see any stressing behavior at this elevated SPL.

Gedlee Distortion (Gm)
The Gm distortion is shown below for the 85dB and 95dB sweep. Gm uses a dual tone test signal and weights the distortion product (Gm) towards types of distortion that we find more offensive than others. Generally we can conclude from this result that the driver is slightly stressed in the upper midrange at the higher SPL, but the overall result is quite low.

I tested the MFC 5" woofer from SB (shown below) and the result was slightly higher Gm for both test SPL's. So the MRX woofer excels in Gm compared to SB's more affordable woofer models. Please note the result below should only be looked at below 2kHz since my quick test was conducted with the woofer mounted in the the 1159 stand mount 2-way speaker.

Conclusion​

The MR13TX-4 is an exciting new product from the SB Acoustic Satori line up. The driver exhibits a very flat frequency response which indicates excellent time domain performance. The distortion profile is consistent in terms the H2,H3, & H4 ladder effect where we see H2 dominant at elevated SPL with H3 and H4 lower down respectively. I personally find this this ladder attribute remains a consistent metric to correlated sound quality. And lastly the Gm metric is very low when directly comparing against the more affordably priced MFC woofer from SB Acoustics. SB Acoustics has done its homework on producing an excellent dedicated 5" midrange.

how sound...this amp work....

This poor thing was going to be thrown in the bin (some will say they would have i know 😉 )-but i saw this as a real challenge as its realy in a bad way.

so here we go this is it, and there is lots to do.
The cover will need to be stripped, repaired and recovered.
The amp, completly stripped down, a realy good clean,get rid of all the rust, reacap
Im going to have to strip this right back to bare bones.

Looking at the set up it might even lend itself to a simpler circuit and laterals??

Hi All,

My first post here (other than my intro)!

I have spent the better part of the past few days going through the internet for crossover design tips and it seems as if it is a little bit of a dark art.

I've prototyped a speaker based on my requirements, built the boxes, got the drivers in and used a MiniDSP to try and find the sound of the type of crossover I am after. This lead me to settle on a 3rd order at 2.2k for both drivers, tweeter down 4db. It seems to give me the power handling I need for the tweeter because of the steeper slope and tames some of the breakup in the 10 inch driver I am trying to cross over (I know - a tricky task!).

Very quickly I have learned that I can't just plug those values into a crossover calculator and so have spent some time learning to use VituixCAD whilst using those calculator results as a jumping off point.

I have managed to get to a point where I am happy with the frequency response plot. The tweeter looks excellent, but the woofer is a bit wobbly - I think that is alright though, it sounds nice in real life.

I'm now at a point where I am on to the phase relationship and how a 3rd order can sometimes be tricky to wrangle.

I suddenly have realised that the phase does not line up properly, especially at the point where it seems to flip.

It looks as if I am about 30 degrees out at the crossover point.

My question is, how important is this in the reality of creating a crossover? Presumably as soon as you move off axis this phase response will change (which brings in a whole new dimension)?

My model is using actual values of components I can order so there isn't a massive amount of wiggle room.

Also as a bonus question, I'm guessing that moving the phase around is more than just about shifting component values until they are ideal? If I change the values of the components, I can never quite get it to show a frequency response I would like - it does shift quite a lot!

I know that the ideal situation is to buy lots of bits and try them out, but I am trying to get it as good as I can the first time round so that I don't have to reorder a whole bunch of stuff - but I do know that with time I'll have more of an inventory at my disposal!

Thank you all in advance!

Hi, just signed up to this DIY forum. Hopefully I will leaned enough to start a DIY project. My current interests are streamer and Dac. Just still on the fence should I buy one of the current all in one box streamer/dac similar to some of EverSolo or build some offerings from Ian.

Hi everyone, hope you're all OK.

I was wondering what is the max safe value for supply voltage of a resistor loaded triode in a common cathode gain stage? Take parallel 3A5 for example; the datasheet mentions max anode voltage value of 130V, and max current value of 10ma (5mA each triode), but how high can the supply voltage go? Can I use for example a 280V supply and a 22K anode load resistor for around 100V and 7 mA at anode?

I know that 100V-7mA is safe for the anode, but how about the warm-up time, when cathode is still cold and internal resistance of triode does not form a voltage divider with the load resistor and in fact the anode voltage is equal to 280V B+; Can this be dangerous for the tube? I mean something like internal arcing?

I was wondering if anyone has a data sheet for a 6240G vacuum tube? A Japanese manufactured tube used in Luxman Amps back
in the day.

If no one has a spec sheet, I am looking for whatever information I can obtain. Absolute maximum plate voltage, maximum working voltage,
typical plate voltage used in the Luxman 3045 amp, Mu, Gm, Plate Curves etc?

Cheers

Pos

Ive begun the process of crafting a preamp following the fine design of the pass aleph p. the idea of building m own stereo was never something id ever considered possible except in my dreams. Thanks to this community and the generosity of nelson pass, ive been able to slowly learn bits and pieces about audio component design structure and function.

After finishing the pass labs pearl 2, designed by wayne at pass labs, and falling head over heels in love with records, i couldn't help but want to build a matching preamp/control deck to pair with it and my turntable.

This forum is to discuss the challenges and success in building a copy of the aleph p for personal enjoyment and education.

Hi, I am 61 yo and totally new to diy in audio electronics, so I hope I'll learn something here. I need to repair a speaker. All the best to fellow members!

Second installment of Plethora of Pinjatas series of amps

Started with this

For Sale 1 pair (brand new but not matched) Seimens D3a tubes.
I am having to move unexpectedly and need to generate a little money otherwise the price would be much higher.
Price is $100 plus $10 shipping

Hello folks. I am Liksel Liston from Australia. I am interested in audio circuit development and trends.

I was looking for information about audio and its design and I found this page.I studied mechanics and electronics, and I made my first amplifier when I was 15 years old. 1985-1987I have been working for 25 years in hardware design, and I have gathered a lot of experience, but after all that, I know that I have learned very little in the vast field of knowledge. I think it is an ideal place to be in contact with people with similar interests and share experiences.
Thank You!

Hi

I am planning to assemble a 6 Channel amp with an active crossover , each amp driving highs, mids and low.

Amps that I have selected is apex ax11 for mids , ax14 for lows and lm3866 amp for highs.

Planning to house all the amp boards in one chassis with 2 toroidal transformers . 1 dedicated for ax14 and the other one for ax11 and lm3866 . I have not yet decided on the psu for these amps. I have gone through many threads where Mile suggests using psu10r and psu15. Please can some one help on this?

Much appreciated

Hi DIY Community , I was interested in electronics since my childhood and the main reason behind that was my dad who assembled amplifiers and repaired consumer electronic items . My dad taught most of the basics when I was very young( 10-16 years) and I never cared to undertake professional training or pursue a career in electronics. Audio and Cameras are two areas where I would like to gain more knowledge and enhance my skills. Currently , I am trying to build a 6ch amplifier with active crossover and I am looking forward to learn more here in this community.

i am not sure if this topic hasn't been around. i understand that real music lovers listen to unplugged records of real concerts but for some reason i like also synthesizers.

i could present this post with music from the 70ties-now but for now i choose 2016 as it is the last one and it is still resonating.

be sure you have loud speakers and tolerant wife, neighbor etc...

...interrupted due to atmospheric interference...

After a period of health issues and thinking diyaudio should better be left to fresh new DIYers (where are they?) I decided to ask if my diyaudio.com account could be enabled again. As doing nothing and not being able to do much creates boredom one returns to old habits but then adapted to the situation. A brand new but damaged AK4493SEQ based SMSL SU-1 (defective output stage) was about to be recycled but then I thought to do something useful with it. Also left were a pair of Haufe quality 1:1 line transformers worth more than the entire DAC. This way the output stage is nearly completely passive and also now the possibility occurred to have balanced outputs via XLR. I added a SPDIF transformer and of course USB bus power was interrupted and a very good ultra low noise linear PSU was used instead. Since there was no opamp output stage anymore the original internal +/- 12V switcher was sent to where it belongs. On the 5V input pins of the retired switcher a Molex KK was fitted to power the power on LED.

All work was done with hand tools. All functionality of the SU-1 is retained except the source indication LEDs that are located on the main PCB are now invisible. The power switch switches the device from standby to powered on with a white glowing ring and a short touch switches inputs.

Publishing is only to show what can be done to make a SU-1 really shine. Due to my non optimal situation a perfect esthetical finish was not possible. SU-1 absolutely benefits from an external linear PSU anyway. Although it is still in testing phase (and not 100% electrically safe, I know) it already sounds better than an Eversolo DMP-A6. To solve is a slight humming issue when no music is playing.

I have a pair of Dynaudio D54 Midrange Domes that I have measured using DAT3 Version 3 and it looks like the Parameters / Impedance are off.

I am assuming the ferrofluid is dried up and requires replacement or removal.

There are 3 screws holding the front horn / faceplate to the magnet assembly. There are "push-pin" covers that "hide" these securing screws.
Is there a way to remove these covers without damaging / destroying them?

Let me know.

Thanks,

Dan

Brand new, never connected or used. The white on the wires on one is foam packing that stuck to them.

Price includes 2 transformers and ground shipping to continental US

$170 Paypal goods and services

Shipping to continental US only.

Hi guys.
Can I use Exicon 10P20/10N20 instead of 10P16/10N16? These are in a TO-3 package. Yesterday, a customer brought me a REL Strata ii sub-bass with 2 blown power transistors.
Looking at the datasheet, 10P20/10N20 are rated for 200V while 10P16/10N16 are for 160V. All other parameters are the same.

I'm rebuilding a Classe CA-401 after one channel blew out. I'm documenting the entire experience to keep track of everything I've done and to help out others. Enjoy!

Every power transistor in the channel was blown. Here's a picture of the vaporization leftovers of the 10N20 and 10P20 gate resistors. Also, check out the 383R VBE multiplier resistor residue in the top right corner:

Is there any info about when BA3 front end boards will be available again? It´s been so long since those boards are out of stock, I hope they are back soon 🙁.

Hello

Thread created to document 'upgrades' to an Audiolab Q-DAC. Hopefully useful to others by the end

This is apparently the M-DACs poorer sibling, but it has proper 8 pin DIP output op-amps and enough functionality to also pose as a pre-amp

This thing wasn't super expensive on a well known auction site so I went for it. I swapped out my STAX DAC talent and the initial reaction was 'meh, well at least it works'

After a week or so of listening it was time to "pop the hood"

So Pictures!!

Andy

I have decided to build the OTL designed by Tim Mellow, which appeared in the February issue of Audio Express. I am considering using 4 6C33C's instead of 2 outputs for more power.
Do you think the driver section will be able to push 4 output tubes? I Would like to hear opinions.
I am planning 2 mono blocks.
Thanks in advance!
dwhitf