Hello,

I am looking for a service manual for KEF TDM45B.

Any help?

Drivers for sale, most of them brand new in a box, some opened but still in new condition.
Notifications have been ticked but i dont receive them for some reason....

Pricing is per driver
Thank you

Hi together,

I just recently started building loudspeakers and amps myself, am new to soldering, still learning about resistors and all these kinds of things and am little bit stuck with a problem.

I have a 2A3 SET tube amp for which I built an amp-to-headphone adapter based on https://robrobinette.com/HeadphoneResistorNetworkCalculator.htm respectively https://robrobinette.com/images/Audio/Headphone_Resistor_Network_Calculator.xls, using the "Three Resistor Network" as that gave me the best values for the load on the amp, attenuation and damping factor. I added two of these with a switch, so I can toggle between them for different sound flavors as well as using it for headphones with different impedances (I have ZMF headphones with 60 ohm and 300 ohm).

For both networks, the load on the amp is around 8 ohm (which the amp is designed for) and the attenuation is almost exactly the same.
Depending on which headphones I use, the damping factors are 1:4 and 1:19 (the 60 ohm headphones) respectively 1:44 and 1:223 (the 300 ohm headphones).

Now, my understanding is that a very low damping factor like 1:4 should give me a bit more boomier bass which is less precise, because the amp is not able to control the driver that well. Other than that I would not expect too much audible differences.

However for both headphones the setting with the lower damping factor leads to much worse sound quality. The soundstage collapses, it becomes very noticeably less wide and everything sounds a little bit less clear. Somehow much cheaper. It is the same on both channels and it has nothing to do with the volume.

I am using MOX resistors everywhere and from what I can tell everything measures fine (the resistances I measure are consistent everywhere, I don't see anything that seems odd). I bought most of the resistors at a local store and I don't know how old they were. They might have been lying there for a while.

Can you help me figuring out what the issue could be? Might some resistors be too old for example? Could I measure anything else besides the resistances in the circuit? The circuit itself does not seem to be the problem as the setting with the higher damping factor sounds pretty good.

I am very confused as both headphones usually sound fabulous, but really cheap with that one setting…

Thanks a lot!

Michael

PS: Sorry if used wrong terms or weird language. As I said, still new to all this 🙂

I have asked member ostripper to lay out a Class AB amp officially called the "diyAB amp" ( nicknamed "the Honey Badger" ) using many of the best characteristics of amps of this type that have appeared on our forums, so that we can feature it in the diyAudio Store. He has agreed to give it a go, is really interested in comments to help it be a paradigm of its type, and will be posting here very soon to describe where the design is at this point.

So pile on!

Mark
"Variac"

Build thread for diyAB Amp: http://www.diyaudio.com/forums/solid-state/211905-diyab-amp-build-thread.html

Simple amplifiers have always been a challenge. Here is the one, single supply operated (24V), 8W amplifier with only 4 transistors, singleton input and bootstrap, with coupling capacitors. The schematics follows:



The amp uses Vbe multiplier (Q10) to stabilize idle current with temperature. Idle current is set to about 60mA.

Frequency response is flat


Stability is very good and feedback factor is low and flat


Spectrum has mostly low harmonic order of distortion components


and THD+N vs. output power


If you asked me if I built it - I did, however lower power 2W version supplied from 15V PSU.

I got an idea that i can´t get loose.
What if we apply current dumping to reduce crossover distortion in an ordinary amplifier.
With an internal feedback of 850 ohms it puts some considerations of the input stage but that can be a later discussion.
Has someone seen a similar idea?

abandoning a project , i have a brand new pair of VOLT VM527 2inch dome driver to sell , never mounted , never used.
my loss is your gain .

wanting 450€ for the pair including shipping to E.U only
thanks for looking.

will not have longer use for them at this moment , i sell a brand new pair of Mundorf dipole AMT tweeter 17D2.2 same as used in the QUALIO speakers

new price 650€ asking 450€ shipping to E.U only

After visiting @Audio Elite in 2017 I knew I wanted to build speakers like that. Slowly but surely I gathered parts. 2nd hand or discounted. Since Stuart was not allowed to share the crossover schematic I had to find something else. But I saw something that was similar to the frequencies I "needed" to cover. I copied that and did a mod for the different tap on the Crites 3636 autoformer. I've posted the crossover pic but here is the complete system schematic..

PS...there is still some work to do on the crossover.

I also decided on open baffle mid-bass. Because I could go active/dsp. And because wood is very expensive.

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Hello! I have a BSR EQ-3000 that I bought back in college (REALLY long time ago 🙂 ) which I recently brought out to set up, as my son is getting into vintage eqpt and vinyl. So I set it up with my Denon and old Bose speakers and cassette deck. Everything worked fine... for about 30 minutes.

At that point the BSR went dark. Turning it off and on produced a flash from the LEDs on the eq sliders, and a mild crackling noise but nothing else (the LEDs flash then go off, everything stays dead). I verified that everything else still works by physically removing the eq from the loop, and tried letting it sit for 30 mins and plugging it in by itself -- same behaviour (see the video).

Any ideas where to start troubleshooting? I haven't taken it apart yet but I fear that's the next step. Thoughts?

edit: can't get the video to show up properly on my post 🙁

I'm selling off some speaker parts that I'll never use. I hope someone else can use them. Brand new condition, open box but never used or mounted together or mounted on a baffle. I never did anything with them.

1. Pair of EOS-8 waveguides. 2-bolt pattern mounting holes. 1-inch (2.54 cm) diameter throat opening. $30 for the pair, plus shipping (they're light and not very large).

2. Pair of DNA-150 HF compression drivers. 1-3/8" T-18 thread screw-on mount, as for Eminence 10CX, etc. $35 for the pair, plus shipping (small and don't weigh much).

3. Pair of 1-3/8" screw mount to 2/3 bolt mount horn throat adapters. $15 plus shipping.

Prices are US dollars.

no signal, bridge.


5hz.


100hz.


2khz.

10khz.



20klhz.


50khz.


100khz.

300khz.

senoidal 20khz.


the preamplifier.

1.177 / 5.000


Hello, first of all I want to make it clear that, as almost everyone knows, Chinese advertisements and clones often do not even look like what they advertise. In this case, I want to make known what I consider a bargain. Leaving aside the title we have a preamplifier that I consider excellent, at a ridiculous price of 10$ with shipping (at least to Spain), small size (easy to connect if you want an integrated amplifier), you only need a 15-0-15 v. transformer, or a switched source for example of equal value for another 7$, it has its regulators, with its capacitors that really work very well, at the input it has an OP JRC-5532D, then BC550 and BC560, everything quite normal, I ordered 2 units, assembled it and passed it through the oscilloscope, the result is excellent (in my opinion and the price) I put captures of up to 400khz in square wave, the sine wave logically better, it responds from 5hz without problems, I have tried other clones and other originals that I have, and this one on paper gives better measurements, something that measures well can't sound bad. The sound, the little I have tried so far, is quite good, better than the Denon 1500pra that I have.
and other clones except the PASS 1.7, for me it is better for more detail, dynamics and width, but for the price it is gold, now here come the more technical forum members (I am not) who could suggest improvements, for the already excellent preamp, I attach captures from the oscilloscope, greetings.

Hi, I have a Mark Levinson 31.5 cd transport which works well for a while and then appears on the display: SERVO RESET. the reader does not obey to stop or change the track, it has to be turned off completely. Has anyone had a similar situation that could repair it? Thank you very much.

I am looking for offers on this last devices I have from Toshiba, I can supply 40 pairs of 2SC4793/2SA1837 and 50 units of 2SC1815GR
minimun quantity to buy is 4 for any part reference.
4 pieces 2SC1815GR 3€/lot
4 pieces 2SA1837 9€/lot
4 pieces 2SC4793 9€/lot
All supplied transistor are from the same lot
Payment by PP
I have more parts from Toshiba that you could check here:
https://www.ebay.de/usr/rocksandsound
Regards

I have for sale the following evaluation boards from Tripath.
RB-TA3020-96€
RB-TA0105-160€
I do have more Tripath amplifier boards that you can check here:
https://www.ebay.de/usr/rocksandsound
Payment by Paypal tracked shipment,shipping to US on request.
For more information PM

I have here for sale severall capacitors from Nichicon used.
1-Raw
Used Nichicon 15000uF 71V 14€/unit or all 8 for 100€
2-Raw
Used Nichicon 12000uF 71V 7€/unit or all 6 for 35€
All used capacitors here for sale have been measured and are within 10% of its rated capacitance
Regards

I recently rebuilt a pair of ESL-63s, and printed some 5 degree tilt back feet, but I don't like having the sound beamed up at my ears from close to the floor, so I designed and built some stands using 1"x1" and 1"x2" t-slot. The stands lift the speaker about 350 mm off the floor, and they are sturdy and center the weight so they aren't easy to knock over.



Details and link to CAD file here. Extra bonus: they are high enough that my cat will probably stop using them as a scratching post.

Yeah, looks like a clickbait but I had such a design target.
Analog Processing Unit contains two devices in the same housing. THAT1510 based preamp-LNA 34/60db gain, 10Vrms max output level, and 48VDC phantom power, just in case if need to work with a condenser mic. The input impedance is 47kOhm 100pF in case it needs to use as a MM phono-preamp without RIAA(Cosmos ADC has internal DSP and may handle RIAA EQ online accurately). The input noise of the LNA is about 130nVrms(A) i.e.
5-6x times fewer than APx555 which, for instance, is not capable to measure the dynamic range of $13 Meizu HiFi DAC, APx555 result is 123-124db(A). Cirrus promises AES17 DR 130db(A) for CS43131, Cosmos APU+Cosmos ADC result is 130.5db(A) with 12db room to APU's residual AES17 DR for 2mV. The LNA's balanced inputs are clamped at 5-6V by TVS thru the 10ohm 0603 resistors in serial to each input i.e. an overvoltage with a good enough current rather may burn the resistors than TVS but that's safe for THAT1510.
The second and biggest half of Cosmos APU is the 1/10kHz active notch filter with -30db ratio(Q about 50) at the fundamental frequency and nearly 0db at 2nd and 3rd harmonics i.e. you can simply divide by 30(or subtract 30db) the THD/THD+N result to get a normal value. Also, with REW or Arta, you can use a calibration file to normalize the notch's frequency response and observe FFT results directly. The max balanced input level is 10Vrms, it is also clamped but by the active clamp with opamp's rail voltage-1V, hence, 10ohm 0603 again may be burned like a fuse. The residual harmonics of the distortions are <-150db@1kHz or <-130db@10kHz, that's probably isn't too spectacular but still better than APx555. The residual THD+N, practically achieved one, -132db@1kHz@10Vrms(DAC+LPF approach), calculations based one is -134db but I can't confirm that so far because of can't find a perfect-zero-noise sine for that 😉 It is clear that APU is kinda a microscope for your ADC, even any laptop audio input with APU gets the ability to measure a tiny noise of DACs or LDOs, and distortion levels are perhaps lower than AP SYS2722 or even Cosmos ADC.
The best way to power Cosmos APU with a power-bank(or a good smartphone charger), is to minimize GND loops issues.
The device is quite simple and inexpensive, strange that's not on the market already. Especially inexpensive(~$70) would be a version without the case as a PCBA which any DIYer can adjust by 4pcs trim-pots(2pcs for the 1kHz Twin-T -30db or -40db, another pair for 10kHz -30db).


REW with the calibration file DAC+LPF->CosmosAPU->CosmosADC


The residual THD+N of 5 preproduction samples, -101db of reading need to subtract 30db i.e. THD+N -131db@9.5Vrms the same about harmonics -127db means -157db







APU Notch frequency responses:





AES17 Dynamic Range test performs at -60dbfs level by measuring the THD+N A-weighted. That plot shows the residual THD+N (A) of the LNA at 1-10mV level sweep. 2mV corresponds 2V 0dbfs DAC like CS43131, and -82db needs to subtract 60db to get AES17 DR = 142db. A typical high-performance DAC with 5Vrms 0dbfs could be measured down to 150db and so on.




The residual noise of 5 preproduction samples(the S2 using SSM2019 instead of THAT1510), the reading need to divide by 1000 due to 60db of LNA i.e. a uV is actually nV.




The gain of Cosmos APU preamp is +60db(1000x times), hence the scale units are nVrms(A). After the APU unit turns On, you can see 5s of settling,
from 6s the input noise reaches 130nV, about 9s 48V power was turned On, and after 1s reached 142nS. Hence, APU's phantom power adds just 12nV to the preamp noise, that's a nearly ideal result as I think 😉 The test was performed with a shorted preamp's inputs(In+ to In-) and biased to the GND by 2x6.8kOhm resistor as a dummy condenser mic.



and the spectrum 20Hz-130kHz of the same test, units need to divide by 1000 as well, so uV becomes nV. This is a good illustration to killing the myth that SMPS is always dirty 😉 Cosmos APU contains no linear voltage regulators at all, only SMPS with Fswitching > 1MHz.



Finally, I got working Cosmos ADC with internal DSP and RIAA EQ implemented for all Fs from 44.1 to 384. A pair of Cosmos APU was used as a dual-mono phono preamp +34db gain with no analog RIAA, which was applied in Cosmos ADC digitally. The video is a comparison of LP vs CD sound, recorded this way.
The formal specs of such a combo:
THD+N@5mV-40ohm(AP output) -83db, and suddenly it places Cosmos APU to the 2nd position of the phono-preamps ASR rating(and yes, I know his tests are silly) 😉


I remeasured Cosmos APU+Cosmos ADC+RIAA max accurate, AC line hum virtually zero.
5mV 10ohm source APU gain 34db Cosmos ADC 1.7V sensitivity, THD+N -89db or -97.7db(A). Due to H2 and H3 being very low, SNR is also 97db(A).


250uV 10ohm source APU gain 60db Cosmos ADC 1.7V sensitivity, THD+N -66db or -78db(A). Due to H2 and H3 being lower than the noise floor, SNR is also 78db(A).


The real SNR i.e. APU source is a cheap MM cartridge AT3600L, the LP record is digitized by Cosmos ADC@32/384, normalized to fit max peak to the -6dbfs, next, the stylus is up to the air, Pioneer PL-300(made in Japan 1980) turntable keeps 33.33rpm. This way the SNR = 91,2dbfs-6db=85.2db(A), that's looks decent if the LP "silence" between the tracks shows SNR = 65db(A) and less.


Of course, both these functions, mic and phono preamp, are features just for the feature list, but I think both are decently implemented and virtually for free so I couldn't call that a marketing 😉

https://e1dashz.wixsite.com/index/cosmos-apu
https://archimago.blogspot.com/2022/05/early-look-cosmos-apu-high-performance.html#more
https://www.l7audiolab.com/f/e1da-cosmos-apu-2/ APx555b measurements
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Some developers of tube amps claim, that for HV power supplies (for anode voltage) only passive filtering (maybe with zeners for slightly shunt regulation) are ensures the best possible sound quality resp best sonic performance. I. e. only one or two inductors and a chain consist of several RC filters. From my experience this is right, as long only top quality elcaps are in use and in the last RC filter additional a MKP version with 50-100uF.
An example are several pre-amp devices from Klimo.

Schematics of first five attached images show such passive versions - i. e. without serial or parallel voltage regulation (except one version in inage 2 with the zeners).
The later attachments show schematics of serial regulators in several variations.

At first glance the benefit of serial and parallel regulators are a very stable voltage, that is additional adjustable in a wide range.
But is it in real live really a fact, that a stable anode voltage provide a better audio than a passive filtered voltage ?
In general I don't think so.

Thank you for comments.

P.S.: some URL's:

HV Serial Regulator
https://tubecad.com/2021/10/blog0546.htm
https://pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Broskie_John/HV_Regulator_OP27_IRF820.pdf
https://www.bartola.co.uk/valves/2015/01/10/popping-the-shunt-voltage-regulators-clogs/
https://www.bartola.co.uk/valves/2012/07/15/new-ht-bench-power-supply-600v/
https://www.bartola.co.uk/valves/page/2/
https://www.tubecad.com/2021/10/blog0547.htm
https://www.tubecad.com/2020/02/blog0493.htm
https://www.tubecad.com/2021/09/blog0545.htm
A commodity-based HV regulator: FlexHV
High Voltage Jung Regulator

HV Parallel (Shunt-) Regulator
https://www.tubecad.com/2006/11/blog0087.htm
https://www.tubecad.com/2021/11/blog0548.htm
https://www.tubecad.com/2021/01/blog0527.htm
https://www.tubecad.com/2007/06/blog0109.htm
Very low parts count shunt regulator

Passive Filter (RC/LRC)
https://www.jogis-roehrenbude.de/Leserbriefe/Carsten-RIAA/Carsten-RIAA.htm
https://www.audionist.de/2015/11/27/netzteil-fuer-einen-roehrenverstaerker-2/
https://www.turneraudio.com.au/audiofilterchokes.html
https://www.turneraudio.com.au/audiofilterchokes-page2.html
Choke ratings and resistor values in choke input supply?

TUBE AMP POWER SUPPLIES (basics to all supply variants)
https://www.turneraudio.com.au/powersupplies.html

croft series 7 HV regulator
https://www.tubecad.com/2021/10/blog0547.htm

Hi there. I have enjoyed a fine Rega Elicit mk2 amplifier for several years. However, recently I noticed that at a certain position of the volume control (or rather the LED track, as the knob has no fixed position) the sound from the left channel disappears, if I turn the control knob (or remote control) a few clicks clockwise the sound reappears, although it is slightly muffled. I checked different inputs, different sound sources - the problem does not disappear, the sound from the left channel disappears exactly in this position of the LEDs. I need your help.

I have twelve (12) brand new 22,000 uF, 80V capacitors. Ordering error from Mouser and I'm stuck with them. I'm trying to recover some funds. Asking $35 each, plus USPS shipping from zip 17402.

4.125 inches tall and 2.5 inches in diameter. Great for all your power amp projects! Send me a PM if you're interested.

Mouser part number: 598-CGS223U080W4C

Hi everybody,

a couple of weeks ago I bought an old Sony CDP-195 (1991/92) at the flea market. The unit was sold for 10 euros as “non working”, so it looked like a good chance to try to learn something about CD players, which I’m not really confident with.

The player looks 95% dead. The only thing (half) working is the tray: it opens but it doesn’t close. It only does If you switch the unit off (with the tray open), and then switch it back on. This leads me to exclude contacts or mechanical problems. Microswitches have been cleaned anyway, as described in Mooly’s CDP-790 thread.

The front panel seem to work: all the buttons respond correctly, displaying the respective mode or symbol (Play, Stop, Pause, Track selection, functions etc.) except that nothing happens.

All the rest is dead. No action by the sled and spinning motors, no movements of the pickup, no light from the laser. When a CD is inserted, the BD Board doesn’t lift up, so the disc doesn’t lock to the platter and falls around.

The tensions printed on the Main Board have been tested and look ok. Discrete components have been tested and look ok.

Anyway, even if the BD board is disconnected (ribbon cable detached), and the player is in stop mode, transistors Q202 and Q208 become hot quickly. Not sure whether it’s a problem or not, maybe it’s just the way it should be, since Q208 has a heatsink.

Tension on pin 1 (+7v) and 6 (+5v) of the BD Board ribbon cable socket are ok on the Main Board side.

I suspect there’s a problem with IC102 (LA6532M), the one that controls the motors. I checked the tensions in Play mode, and I have just 2,7v on the pins 18/19 (controlling the spindle M) and 0v on pins 12/13 (controlling the Sled M).

I’m tempted to replace the IC, but I’m not 100% sure. I read everywhere that replacing the laser unit will solve almost any problem, but I suspect this time the fault is elsewhere.

Any suggestion will be greatly appreciated. Thank you.

--------

PS Service Manual attached

PPS For the ones following my other thread about the infamous Transylvania cassette recorder/player, the unit is still on hold, but I haven't give up. Just had enough of it. Sooner or later I'll come back to it.

Hello Friends

Geneva Audio Classic/XL great simple looking speaker and config. 2 tweeters 2 5.25woofers and 2 - 8" woofers ported​

Wanting to build a powerful All in one box for parties and moe around the house. I want more bass pressure I dont get from Marshall Woburn or Bose S1 speakers at home.

Can you suggest the combination Thinking of using the Dayton KAB 4x100 bluetooth amps that also have DSP. Unfortunately they Dont have AirPlay 2
I was also wishing if TPA 3255 based amps had some DSP built in

In Drivers please suggest Peerless or SB or last option Dayton

regards
anand

This amp uses only 2 transistors, one J113 JFET and one BD139.
And only 4 resistors.
What is different is there is no feedback.
Because of this there is some distortion, THD 0.5% at +10dB into 32 Ohm.
The amp should probably work into headphones 16-600 Ohm.
But the design was only developed using 32 Ohm.

PCB available in the diyAudio store here -

M2X – diyAudio Store



A First Watt "M2" amplifier without (or with!) 2SJ74 / 2SK170 JFETs

After Burning Amp 2017, member 6L6 and I drove to San Francisco airport and naturally we talked about diyAudio the whole way. We imagined that many people would love to build a DIY version of the First Watt "M2" amplifier -- except that the M2 requires JFETs which are painfully difficult to source. Toshiba has stopped making them, and the Linear Systems replacements are hard to find too. (The diyAudio Store has been sold out of the most sought-after Idss grade for months and months).

HOWEVER, we noticed that the JFETs were used only in the "input stage" of the M2 amplifier, to implement a unity gain buffer that drives the primary of an autotransformer. The remainder of the M2 amplifier uses components that are in active production, available from multiple different distributors, today.

So I proposed that we lay out a new PCB for the First Watt M2 amplifier, with the input stage and its Unobtanium JFETs contained on a removable, replaceable, interchangeable Daughter Card. Now we can build input stage (unity gain buffer) daughter cards, with whatever components we wish. Of course one option would be (should be!) Nelson Pass's original design using Toshiba JFETs, for those who are willing and able to obtain them. And there will be other options too. Options that implement a unity gain buffer without Unobtanium parts. Fortunately it is not an impossible task to design a unity gain buffer which fits on a small daughter card.

My feeling was: let's make it possible for people to build and listen to an M2 amplifier, at the same time they search the globe for JFETs. Months later, if and when they succeed in finding and purchasing JFETs, they can stuff and solder the JFETs onto a daughter card, swap it in, and keep listening. Or maybe, just maybe, they'll fall in love with the sound of the M2 without JFETs, and quietly stop searching.

As we drove along and discussed it more, both 6L6 and I came to the conclusion that this sounded like a pretty exciting idea, and I began to work on the PCB layout and the input stage circuit design(s) during hobby hours.

I'm now pleased to announce that revision V1 of the M2x amplifier has arrived. PCBs for the amplifier left and right channels (the "mother" boards) have been built. PCBs for five different input stage circuit designs (the "daughter" boards) have been built. I've shipped all PCBs and all daughter boards and all electronic components to 6L6's electronics lab, for one of his beautiful Build Guide jobs: Assembly and Step By Step Photography. I'm very pleased to say that he has built the amplifier and a few of the input stages. It works. It sounds good.

But 6L6 has a full time job and must fit diyAudio into his spare time. The Build Guide is not yet complete and won't be complete for a while longer. Similarly, my own build of my own M2x amplifier has begun but it is also not complete. That's how hobby projects work.

While we wait for the Build Guide to arrive, I thought readers might enjoy looking at the circuit schematics of the M2x amplifier and its five different input stage options.

I've given each of the input stages a code name, derived from the city where its input devices were manufactured. (As best as I was able to learn which fab made which devices). The five M2x input stages we have today are

1. ISHIKAWA - Nelson Pass's original M2 input stage circuit design, using Toshiba JFETs made in Ishikawa, Japan. The PCB naturally also accepts Linear Systems JFETs.

2. MOUNTAIN_VIEW - A single ended, class A unity gain buffer circuit design, using the J112 JFET made by Fairchild in Mountain View, California

3. TUCSON - An unity gain buffer circuit using a high performance Burr Brown opamp, built in their fab in Tucson, Arizona

4. NORWOOD - A two-chip unity gain buffer using an extremely high current video driver IC, plus a front end JFET opamp made by Analog Devices in Norwood, Massachusetts.

5. AUSTIN - A BJT complementary "diamond buffer" using Motorola (now ON Semiconductor, owner of Fairchild) high Beta bipolars, built in Austin Texas

How might someone choose which of these to build? (Or, which of these to build first?) Here are some thoughts.

ISHIKAWA (using Toshiba or LS JFETs) has the absolutely lowest parts count and is the easiest to solder together. But those FETs are hard to find.

TUCSON using the thru-hole OPA604 chip, is the lowest parts count board that doesn't use unobtainium devices. And the OPA604 opamp has JFET inputs, so if you love JFETs, it's one of the opamps you probably know and adore.

TUCSON using the SMD OPA1611 chip, is the lowest distortion input stage of them all. Even lower than the Nelson Pass original. It only has one surface mount part; the rest of the board is thru-hole.

NORWOOD is all-SMD, just like the entire electronics industry has been for the last 20 years. Norwood includes a 200 mA driver IC, and a JFET input opamp from Analog Devices. Its output current capability is at least a factor of five greater than any of the other M2x input stages. If you're at all concerned about the input impedance of the output devices at HF, reflected from the transformer secondary back into the primary, Norwood can drive it better than all the others.

MOUNTAIN_VIEW uses single-ended, class A, discrete circuitry and no feedback. If you are a big believer in single ended class A, if you love this quote from a famous article by Nelson Pass: "For reproducing music as naturally as possible, push-pull operation is not the best approach. Air is not symmetric and does not have a push-pull characteristic. ... Only one linear circuit topology delivers the appropriate characteristic, and that is the single-ended amplifier. Single ended amplification only comes in pure class A," then you probably are interested in listening to the Mountain View input stage. Parts note: please see post #3318 in this thread if you're having trouble finding a few MV5075C LED parts. That post suggests alternatives.

AUSTIN is a thru-hole board with 4X more components than the other boards; its resistors are mounted vertically to save PCB area. This permits a Diamond Buffer circuit with high performance, precision current source loads. Builders who love parts substitutions / optimizations will appreciate that Austin's PCB silkscreen doesn't indicate transistor orientation. Instead, transistor pins are labeled B, C, E in a perfect circle; allowing you to drop in Japanese 2SA/2SC transistors (pinout ECB) or European BC transistors (pinout CBE) or American 2N transistors (pinout EBC) however you please. Austin is recommended ONLY for experienced builders. If you're a newbie, hire someone to solder your Austin board!!


What happens next?

First, 6L6 and I work on finishing our respective M2x amplifiers in our respective spare time. This includes building and listening to all versions of the input stage daughterboards.

Second, 6L6 posts his photographic Build Guide here on diyAudio.

Third, if the amplifiers work well and sound good, I'll offer my approximately 30 sets of PCBoards (2xAmp plus 8xInputStage per set), if anyone wants to try the M2x.

Fourth, if I happen to sell out, 6L6 and I will put our heads together to figure out the next move.

Schematics and BOMs attached below in .zip file



edit- if you are wondering how a correctly-built and properly function M2x will appear during a dim bulb test, see (a post written in Sept 2019) and also see (another post written in Oct 2023). They show you what to look for.

~

Am I missing something? I can't seem to save the filter settings for the forum so I end up re-entering them every time.
Any thoughts? Problem Exists Between Keyboard And Chair?

Background – I’ve built speakers in the past but my most recent build was in 1999. So I am trying to read and catch up with current speaker building trends.

A lot more attention is being paid to off-axis performance these days. I gather that consistent and as wide as possible directivity are said to give a more realistic sound. That said, I am seeing two different approaches to off axis in tweeters. I have borrowed a couple of normalized off-axis curves from hificompass.com to demonstrate. Many thanks to them for their fine measurements.

Some folks are trying to keep the widest directivity to as high a frequency as possible followed by a smooth narrowing at higher frequencies. An example of this is the BlieSma T25S-6 where there is no narrowing of the off-axis curves until about 6.5k Hz. Then it narrows linearly until a break-up in the 17k – 20k region.

Others prefer an early but smooth narrowing, often accomplished with a wave guide. An example of this philosophy is the Satori TW29BNWG-4 which uses a wave guide and starts narrowing about 1300 Hz. As it happens, hificompass.com offers 3D printer plans for a the BlieSma T25S-6 which changes the T25S-6 into something like the Satori.

My question is which kind of directivity pattern is preferred and why? If it’s just preference, what are the advantages and disadvantages of each.


Thanks.

I'm adapting an existing ps to supply +/- 15-20 vdc to preamp boards that draw zbout 55ma per rail. I'm planning to use an existing transformer and have a simple PSU board to adapt with spare parts to provide the vdc to the boards I've built. Once the AC from the transformer (23-0-23vac) has been converted to VDC via a bridge rectifier it then has some bulk caps. The output voltage is, however, 31.8vdc (unloaded) and I'm looking for a simple way of reducing this to 15-20vdc bearing in mind the 55ma draw of each board. What would you good folk recommend to achieve this? I have a simple option on the existing board to insert a through hole component... The boards have regulators so I just need stable raw power supply that can handle the current draw without smoking...

Building the Pass/Firstwatt F4

This is a fantastically good sounding amp - read more about it here before staring;

https://www.firstwatt.com/wp-content/uploads/2023/08/prod_f4_man.pdf

The thread at DIY audio -

http://www.diyaudio.com/forums/pass-labs/97540-f4-power-amplifier.html

And this the the corrected schematic (The schematic in the Firstwatt article has a typo, also this one agrees with the PCB)



Here you will find a build guide for the Pass / Firstwatt F4 power amplifier using PCBs and chassis from the DIYaudio store.

The 5U 'BIG Amp Chassis' is shown, because that's the one I have. It will fit comfortably in a 4U 'Jack of all chassis' and have enough heatsink as well.

~~~~~

There are plenty of places that you could start, but for the sake of illustration let's begin with the heatsink assemblies -



This is the heatsink(s) from the 5U 'BIG Amp Chassis' It has a mirror-imaged set of pre-drilled heatsinks and brackets to hole them together and make a mounting point for the rest of the enclosure. The 4U is similar, but the heatsink is a single piece.




This build will also utilize the 'DIY friendly' baseplate, here shown with the feet and hardware, and also the heatsink's brackets.


There is a hardware package available for the pre-drilled back and heatsinks, including input and output jacks, IEC module, and hardware for the PCB and heatsinks.


The contents of the hardware bag.


Using the brass PCB standoffs, install them into the PCB mount holes as shown, to get the following pattern;


Now there is a place to mount the amplifier PCB


Speaking of PCB, it's a very nice layout, plenty of room, and the ability to use many sizes of resistors and caps. This is the front.


Here is the back.


Stuffing the PCB should be done in the usual order, from smallest device to biggest - so that would be diodes and resistors first.

Of note, I got the bigger (Dale/Vishay RN60) resistors to see how they would fit on the PCB. They are the size of the PRP resistors that are quite popular amongst the fancy parts crowd. They are great everywhere except the row flanking the small transistors right in the middle. They don't fit there side by side. You could mount them soldier style, or just mix in a few smaller resistors like I did. Or just get RN55's. They are the smaller size.


Pots and transistors next. (yes, I didn't stuff the input pair when the photo was taken…)


Ah, there they are.
The ziptie is just to help their thermal tracking.


And finally the capacitors.


There is a top and bottom to the Universal Mounting Spec holes, the board mounts as shown


I find it helpful to bend the leads of the transistors first, and mount them (a little bit loose) to the heatsink.


Like this


And then mount the PCB. You can snug all the screws down and then solder and trim.

Ok, now lets move on to the Power Supply.


Here is a photo of the PSU board, I am going to use integrated bridge rectifier blocks, so you need to remove the part of the PCB that mounts the diodes. The new PCB, not quite yet available at the time of this writing, will have a similar feature with the diodes, as well as room for more/bigger capacitors.


As always, stuff the small components first - the light blue resistors are the filter resistors, the darker ones with the teflon are the bleeder resistors, and the small ones are for the LEDs.

This PSU board is the exact same DIYaudio PSU board, just without the top blue soldermask.


This shows the INPUT edge (from the diode bridges)

The capacitors are Panasonic T-UP 33,000uf 35V


Connecting the bridges to the PCB




This is the OUTPUT edge of the PSU - the colors are
Red V+
White GND
Green V-
The black connects the PSU GND to the CL-60 to the chassis.


The wiring from the PSU to the amp PCB is clearly shown.


Here you can see the bridges with the wires attached from the transformer secondary. Remember that the green attached to a bridge must have continuity with the blue attached to the same bridge. (As it's the 2 ends of the same piece of wire)



As long as were are tailing about the transformer, here is a photo of the terminal block shown wired for 120v. The Blur lead is the AC Live, and the clear the AC neutral. The reds and blacks are the transformer primaries.

Transformer is an Antek 400VA 18v+18v, part number AN-4218.



The last bit of the PSU wiring is the chassis connection, the black comes from the PSU GND, and the green is the AC safety earth.

The AC to primary wiring confuses everybody, so;

Let's look at the PSU schematic just to make sure everything is OK... Remember that I am wiring it for 120v operation, so the transformer primaries are in parallel. People wiring for 240 with a transformer like this, please ignore.



Notes in red are mine.

Look at the connections of the transformer primary, through the thermistors and line cap, to the mains.

Hot AC is connected to the "120" (which in my case is the red leads on the primaries) One red primary is connected to AC hot through a thermistor.

Neutral AC is connected to the black "0" leads, one of which is connected to the AC through a thermistor.

AC Hot and Neutral have a cap across the leads.


So, yes, the AC will be connected to the center 2 posts, which is across the cap.


(This photo lifted from my F5 thread, but it's the same PSU…)

Left to right we have post 1, 2, 3, 4

POST 1 - Transformer primary 'B 0' which will be connected to AC Neutral at post 2, through the thermistor between post 1 and 2.

POST 2 - AC Neutral in (not shown in photo), connected to Transformer primary 'A 0" , a thermistor to post 1, and a line cap to post 3

POST 3 - AC Hot in, connected to transformer primary "B 120", thermistor to post 4, and line cap to post 2

POST 4 - Transformer primary "A 120", connected to AC Hot through the thermistor to post 3

If you look at the red and black wires in the photo you will see that the Mains AC must to pass through a thermistor to connect to each of the 2 primaries. And that is the point of them, to keep inrush under control during powerup.

Ok!

Now we need to put everything together -

But first a bit more mechanical assembly.


This is the pre-cut back plate and the thick front plate.


Gather and mount the IEC plug.




The speaker posts.




And the RCA jacks.

Note that the shoulder washer goes on the inside, so the metal of the chassis doesn't touch the metal of the jack. There is a similar washer on the speaker posts.




The inside of the back panel.


And the outside. Looks good, yes?


The IEC module is wired as shown. This will switch both the Live and Neutral. The blue (live) and clear (neutral) go the the wiring block with the thermistors, cap and transformer primaries.


The amp PCB completely wired.


A bit closer.


The top connections labeled.


This happens to be the other channel, but the connections are all the same.

Remember that V- / GND / V+ is always left to right as you are looking at the format of the PCB


I'm not entirely sure what I was trying to show here, other than the screw and washer. It looks cool. I will keep the photo in the guide.





A few notes on bias -
P1 controls the bias, measured across any of the 3W source resistors. Adjust for 0.13v when it's cold, and watch that it doesn't get higher than 0.2v once it's up to temperature in about an hour. Adjust for 0.2v when hot.

P2 is used to adjust the DC offset on the output to zero.


Attach a DC voltmeter across the speaker outputs to measure offset.




If you find that the P1 doesn't have enough range, I.E., you can't turn it up enough, replace R9 with a smaller resistor, I used 4.75K and it works well.



Connect a voltmeter across any of the source resistors. The outboard ones are easier to clip across.

Adjust for about 0.13v cold, and once the amp is up to operating temperature, trim for 0.20v - It takes a long time to warm up, take your time.

Adjust P2 for zero offset, then re-trim P1

Here is a photo of it all connected and working -



I'm driving the F4 with an O2 Headphone amp sourced from an iPod; Driving 85.5db speakers. Although it is a small room, it gets louder than I want to listen. It still can't drive it to clipping, but it does get really, really loud.

One thing worth mentioning, and it speaks very highly to the quality of the amp, is that it is completely non-fatiguing, and more interestingly, very easy to listen to turned up too loud… I don't realize how loud it actually is sometimes. Complete transparency is a word used a lot when describing this amp - but I have to agree. It's fantastic!





Please comment away if you desire.

Also please feel free to ask any F4 questions here, and if you would like to post photos of your F4 completions, old or new, please do!

dear all,

Please allow me to anounce:

http://www.tentlabs.com/Components/Tubeamp/Tubeheater/index.html

also the backgrounds might be of interest

http://www.tentlabs.com/InfoSupport/page35/files/Heatingmethods.pdf

enjoy

Guido

I bought A old Fisher MT-6330 DD turntable, I would like to bring it back to spec performance. At best is has a peak 2S wow at 0.093% giving a DIN W&F at 0.037%, but more often the peak is 0.14 and DIN 0.05 . It is very sensitive to user adjusting speed pots, and speed oscillates several seconds if platter is disturbed.
Almost like the servo gain is too high .

spec is 0.035% presuming DIN as source is the german manual.
I can find settings for reference voltage and DC balance, but now setting for servo gain.

I am going to clean potmerers for speed setting both internally and the user speed pots, and set the motor drive DC balance according to service manual .
But What about adjusting the servo gain when there is no variable resistor for i?
What else can I do?

I have a rather large stock of NOS MOSFETs. New and used.

New are $20/pcs, used $15/pcs.

Ships from Sweden.

Thanks for looking.

R Malmin

I have a 8 channel active setup. When I want to take a sweep in Rew I only have the option to playback one channel at a time. output is 1 to 8 but I want to measure the response on all of them.

I use Audiolense to create correction files. Playback in Roon.

CEC (C.E.C) claim by their mostly amplifier models, it's class A (here in Germany even "Pure Class A") The name of circuit topology is "LEF (Load Effect Free). The developer is Mr. Carlos Candeias. Have a look to this URLs: Amp 3300R:
CEC AMP3300R
and Amp 5300R (Amp5300R Amp 5300R Amp5300)
CEC EUROPE WEBSITE
The last model delivers 120W/8 ohms and 135W/4 ohms, as to read in the CEC datasheet
If anybody can posted the schematic of one of both models, I will make an evaluation. I guess, the term "Pure Class A" is concerning the pre-driver stage and driver stage of a push pull complementary CFP resp. Sziklai pair, but I don't know this exactly.
If there really pure Class A by the output power devices, where is a heatsink with the appropriate sizes?
Thank you very much for your posted schematics in advance

Hi everyone,


I’m wondering if anyone could help me identify the capacitors used in the Canton Fonum PC 210 speakers.
Unfortunately, I can’t read all the values on the original capacitors, and I haven’t been able to find any information online about the crossover specifications or component values.


Any help, photos, or schematics would be greatly appreciated!


Thanks in advance!

Hi everyone! I'm passionate about vintage audio and enjoy modifying and upgrading old amplifiers to achieve a rich, warm analog sound. My current setup includes a JVC RX-308 amplifier upgraded with OPA2134PA opamps and a Yyaudio P-037 power cable. I'm running Canton Fonum PC 210 sealed 3-way speakers, which I’ve internally rewired with Neotech STDSPCT-22 silver-plated OFC copper cables using lead-free solder with 3.7% silver content. External speaker wiring is done with 2×2 meters of KáCsa KCE-LS25 cable. For vinyl playback, I use a JVC AL-A151 turntable with an Audio-Technica AT85EP cartridge, an acrylic mat, and Sommer Cable RCA interconnects. I'm always striving to extract the most musical, natural and analog character from these classic components.

I have two Thor subs, each with its analogue crossover. With peerless xls 12" drivers. At present crossover set at 50hz I think. I am not guaranteeing the crossover is working, but they were working when made up.

I've never used these, and so they need to go to someone who will.

Each individual subwoofer with its crossover £150.

Collection from Guildford Surrey. No posting for obvious reasons... 🙂



Thanks.

My Topping DAC D50 does not power on. I tried different USB charger 5V-1.0A and 2.0A.

Did anyone experience the same problem?

I hear it "click" on, but indicator light (display) does not light up. Has anyone any ideas how to get it working?

Thanks.

Hi everyone,

I’m completely new to the world of hi-fi and DIY audio, and I’m really excited to start this journey. I’ve recently developed a fascination with high-quality sound and have been exploring.

While I don’t have a technical background, I’m keen to learn — whether it’s about amps, speakers, or the basics of audio electronics. I joined diyaudio.com to connect with others, ask lots of (probably beginner) questions, and slowly build my understanding of this amazing hobby.


Looking forward to learning from all of you and sharing my progress as I go. Thanks for having me here!

diyaudio.com has accepted me as user

Back in 2012 I had a website up in DK with DIY hifi amplifiers, speakers and circuit diagrams as well as vintage gear, which worked until 2019. In 2019 people who had gained access to my PC data wanted me to pay for the content, which I refused.
Due to a virus on my old PC, all files and data disappeared, where hackers without a real reason that I knew of, deleted my files.
Because of this I had to remove the remains on the PC myself, I lost all my contacts and connections and gave up on restoring my PC as it was......

Since then I have been working on refining tube preamplifiers and am currently putting together a line amplifier based on the Marantz 7 circuit and The Paravicini 834P phono stage.

But before I get to the point where I can show you a complete DIY amp based on the two mentioned amplifier circuits, I would like to know if there are others here at diyaudio who work with tube preamplifiers and transistor regulated power supplies on amateur basis? I have some info to show for interested hifi people at the link shown:

https://sites.google.com/view/tubeamp-dk/the-aurora

After I completed the ”New” Dynaco Pas 3X in 2025, the amplifier has undergone several listening tests in direct comparison with other tube preamplifiers with almost the same circuit topology. The starting point in the test is amplifiers that all comply with high high fidelity standards and a frequency response that far exceeds the limits of human hearing.

Starting from the extra good high fidelity standard, there are many reasons why a tube preamplifier sounds good, since human hearing is not a stationary function, but a sense that changes over time, while the perception that the brain has available when interpreting sounds also changes.

Therefore, well-known pieces of music can be perceived differently by the same person depending on how the brain processes certain sounds and tones that day.

That said, the three tested tube amplifiers have some common features, as they all use audio tubes of the 7025 / 12AX7 type, and that all three amplifiers have been subjected to a critical listening panel of experienced hifi people.
The listening panel preferred “The Aurora” as the most musical amplifier followed by Elrad’s “Röh-1” both with regulated high voltage +B.

Fairness regarding listening quality and testing as well as objectivity will never be neutral, as every person with electronics experience has already formed their own reservations about the amplifiers based on the known circuit diagrams.

Therefore, only the diagrams are presented for review, as well as a link showing how the Dynaco Pas 3X and “The Aurora” are put together.
The German variant “Röh-1” has yet to be recorded and shown on the aforementioned site, while “The Aurora” is freely available.

One parameter that affects the sound signature of the three tube preamplifiers to a greater extent is the power supplies, where the Dynaco Pas 3X is the only one that does not have a transistor regulated supply. All three preamps have approximately 1K in output impedance.

Write back if you find this interesting?

Best regards Kim, DK

Edit: 1. Google offers free space for a amateur site like mine, where more space is allowed for uploading images...
2. I am retired optometrist and autodidact within electronics..there might be errors 🙂

Has anyone gotten a Raspberry Pi 5 to work successfully as a DSP crossover music streamier?

I have a working DSP crossover streamer configuration on my Raspberry Pi 2B using Charlie Laub's ACDf filters. The OS is Bullseye 5.10.103-v7+. The 2-channel (stereo) audio stream from mplayer (using -ao alsa) is successfully split into multiple channels and processed by the filters in /etc/asound.conf and this outputs multi-channel PCM 96khz to my AV receiver via HDMI and the resulting sound quality is excellent in my 2.5 way speaker setup. The tweeters go tweet, the squawkers go squawk and the woofers go woof!.

With my new Raspberry Pi 5 running Bookworm 6.6.20+rpt-rpi-27172 I have not been as successful. With sudo raspi-config I have selected 1 PulseAudio (only other choice is 2 Pipewire) and audio output 0 vc4-hdmi-0. On the GUI desktop, I have the options for Stereo, 5.1 Surround, and 7.1 Surround. I have installed the ACDf filters in the (I believe) correct folders /usr/lib/ladspa and for good measure also /usr/local/lib/ladspa, and I have alsa configuration in /etc/asound.conf.

With 7.1 Surround selected on the Desktop:

In terminal
$ speaker-test -t wav -Dpulse -c 8

speaker-test 1.2.8

Playback device is pulse
Stream parameters are 48000Hz, S16_LE, 8 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 24 to 262144
Period size range from 8 to 87382
Using max buffer size 262144
Periods = 4
was set period_size = 65536
was set buffer_size = 262144
0 - Front Left
4 - Center
giving sequential 8 channel audio output Front Left, Front Center, etc. to all 6 drivers in my system. The audio is mismatched with the drivers, but I had the same issue on the Raspberry Pi2 and corrected everything using the t-table in /etc/asound.conf.

In terminal
$ sudo speaker-test -t wav -Dpulse - c 8

speaker-test 1.2.8

Playback device is pulse
Stream parameters are 48000Hz, S16_LE, 1 channels
WAV file(s)
ALSA lib pulse.c:242🙁pulse_connect) PulseAudio: Unable to connect: Connection refused

Playback open error: -111,Connection refused

In terminal
$ sudo speaker-test -t wav -Ddefault -c 8

speaker-test 1.2.8

Playback device is default
Stream parameters are 48000Hz, S16_LE, 8 channels
WAV file(s)
ALSA lib pcm_params.c:2226🙁snd1_pcm_hw_refine_slave) Slave PCM not usable
ALSA lib pcm_params.c:2226🙁snd1_pcm_hw_refine_slave) Slave PCM not usable
Broken configuration for playback: no configurations available: Invalid argument
Setting of hwparams failed: Invalid argument

Using the sudo causes the action to fail.

mplayer (using -ao alsa) now gives audio output to Front Left and Front Right channels only at 44.1khz which is the same 44.1khz as the internet radio stream indicating the resampling of /etc/asound.conf is being ignored.

mplayer (using -ao pulse) gives audio output to all channels at 44.1khz which indicates the resampling of /etc/asound.conf is being ignored. This is confirmed by turning off all the outputs in the t-table.

aplay -l reports the following.
** List of PLAYBACK Hardware Devices **
card 0: vc4hdmi0 [vc4-hdmi-0], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: vc4hdmi1 [vc4-hdmi-1], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0

I know that PulseAudio is looking at the configurationi in /etc/asound.conf because I can comment out a formatting character such as #} and this will throw an error with mplayer. It just appears that the filters are being ignored by PulseAudio. Maybe the Pi5 OS being 64bit and the filters were written for 32bit has something to do with it?

The Micro-Audio SMPS600-R2 is a high-quality, unregulated 600W switching power supply designed for audio applications. It offers a single-rail output of 46Vdc. SMPS was bought few months ago and it is in perfect working condition. Dimensions are 187x123x50 mm and weight is around 800g.

This SMPS is designed to power various TPA3255 amplifiers, like 3e modules and others. It provides significant sonic upgrade, compare to cheap SMPS.

I paid around 200 EUR (all shipping costs and custom fees included) to import it to Slovenia (EU). My price is 125 EUR + shipping + PayPal fee.

In recent exchange (by PM) I got asked if it's possible to do a tower version of the Open Source Monkey Coffin (OSMC). My gut feeling is that it shouldn't be too difficult to modify the OSMC design into a Open Source Monkey Tower. I am therefore starting this new thread to discuss the tower idea.

Sad to hear about Rick's passing. He designed some speakers back in 2007 for me. I was wondering if anyone knows who still has access or owns his designs? I'm looking to build some speakers (RS180 + 27TDFC) that he had designed that tonally match the ones he designed for me (RS150 + Peerless HDS). Does anyone still sell his designs or have access to them?

For sale a very rare pair of Titanium JBL tweeters perfect working condition.
Never been repaired.
250 Euros+shipping.

This thread is for people to discuss their builds, build issues, and parts for the DIY Class A/B "Wolverine" Power Amplifier.
The boards are currently available through group buy's when they are held.
@jjs is servicing the USA and Canada regions.
@stuartmp is servicing the other regions.

Main Thread:

Wolverine 57v & 64v Schematic:
Please see the attached PDF files. These schematic show.
The Wolverine IPS - V3.7 (1st Group Buy) & V3.8 (2nd Group Buy)
The Precision EF3 - Both

BOM and Build Guide documentation:
Currently only available to group buy members.
In time will all be posted publicly once the group buy members have had time to order parts.

YouTube Build Link

Google Photos - Wolverine Build Album

Review Attached by @fireanimal 30-06-22
Review Attached by @richbandit 05-08-23 or at post #2,493

Posts of Interest
#

There is also a distortion sweep plot of the Wolverine below with the values listed for 1K, 10K and 20K.
A big thank you to Andy for taking this measurement for us. 🙏

17-3-23
we finally have 20k distortion measurements.
0.000095% THD 80 watts 8 ohm load.
Thanks again Andy for providing these amazing results
More test results can be found at the end of the build guide.

-------------------------------------------------------------------------------------

Announcing the Wolverine 5th Group Buy - Pre Order Open Now!​

Register for the Wolverine 5th group buy

Came in with blown power supply. Replaced PS fets, gate resistors and ucc27524 driver.

When I apply power, no remote, the ucc27524 shorts its outputs(pins 5 & 7) to ground with 5.4 ohms resistance. This also happens with the fets removed. I tried another ucc27524 and no change. Parts are from mouser and work in another amp I have here with the same driver(stetsom ex6000eq).

With the ucc27524 removed I can see drive signal on both input pins(2 & 4). I get 12volts on the vdd (pin 6) and ground on pin 3.

After a few minutes disconnected from power the short goes away.

I am at a loss.

Is there anything fundamentally better about a discrete r2r DAC as opposed to an IC?

I need schematic diagram of Unison Research Unico to take pre-out amp.
Please help me?

Dear friends!
I am assembling a headphone amplifier. I have a question: how to correctly calculate the value of the potentiometer RV1? I heard that it should be about 10 times less than the input resistance of the amplifier. In my case, the input resistance is determined by the value of R12 and is equal to 33k. Then I need a potentiometer of 3.3k? But everywhere where I studied the circuits of similar amplifiers, they recommend a potentiometer value from 10k to 100k.
How to choose correctly?

PS. Input signal goes from PCM2704 DAC (recommended output impendance 10k or more).

I just downloaded a file from there; it's the first time is about a year I've been able to. Might want to check yours as well?

Anyone use their leftover / extra Car Audio stuff for home HiFi? One would think - by now - the name brand car audio stuff would have specs that far exceed what is considered good for noise, distortion, frequency response et al. 12V power shouldnt be a mountain to overcome...

I picked up a Rockford Fosgate R-150 / 2 at a gamble price; the blue light came on when I powered it up. Sounds good to my ears in my garage system. I'm going to try a FRFR for guitar / vocal with it, with two FR speakers and amp / cab models upstream.

Hello all,

Here are some Triplett VU Meters from an MCI tape machine

Fits 5000 series consoles and JH-100, JH16 and JH-24 open reel tape machines

In excellent condition & Working perfectly

Genuine & original part dates from late 70's- early 80's

Top quality meter, Made in USA

Includes built-in diode bridge for AC operation

Meter measures 70.3mm x 60.9mm x 46.7mm deep excluding terminating posts

Complete with bezel 79.3mm x 43.6mm and mounting nuts

But without the tabs to secure the bezel and meter assembly to a panel

Requires a 75.4mm x 39.8mm panel cutout for the bezel

Perfect for MCI replacement or other vintage gear restoration

8x of these meters and bezels are available

I'm thinking USD 45 each plus postage or open to offers for multiples

Cheers, Ralph

https://audiofile.net.au/

Does anyone know where I might find these or equivalent.
The amplifier is a Sundown Salt-6

Can TIP32C or MJE3055T be used for B631K?
and KTD600K-Y or 2SD600K) for D600K

What would be a good combo?

Thanks

Contracted manufacturer to install 1.0mm pin sockets in Magnoval bases. Tested on 12GT5 Novar tubes.
Money back guarantee if not satisfied with fit. Background link below.
$2.50 each + ship to US, Canada.
Thanks,
Jim

https://www.diyaudio.com/community/threads/real-novar-sockets-inside.397358/#post-7304388

A friend recently lent me a Dayton DATS LA to test. Dayton advertises that the DATS LA is capable of performing small- and large-signal analyses. This review focuses exclusively on large-signal analysis, or rather, the part of the program known as " Symmetry Test." Further details and the associated patent can be found on the Dayton website (https://www.daytonaudio.com/product/2090/dats-la-loudspeaker-analyzer). The patent—probably not entirely unintentionally—suggests a similarity to the Klippel analyzer. However, that would set the bar quite high.

Before we get into the measurement results, a little more information about the Dayton DATS LA. I believe the measurement principle was already introduced in 1992 by Blind, Phillips, and Geddes at the 93rd AES Convention, although they used a different measurement principle (DUMAX) in their publication.
Fig. 1

The patent specification, published on the Dayton Audio website, also refers to this source. According to the patent specification, the loudspeaker is to be excited with a very low-frequency alternating voltage and a superimposed 0.7-second sweep.
Fig. 2

The real measurement signal or a measurement run looks like this.
Fig. 3
Fig. 4

The operating point is set using a modified "square-wave signal" of approximately 0.33 Hz, and the impedance at the operating point is then determined using a 0.7-second sweep. Obviously, the measurement is not performed alternating between cone in and cone out as shown in Fig. 6, but rather continuously decreasing in 19 predefined steps, resulting in 19 impedance curves , as shown in the following figure.

Fig. 5

It is inevitable that the voice coil will heat up when exposed to direct current. DATS LA attempts to reduce this undesirable effect during measurements by varying pause or cooling times. For example, a measurement cycle with ± 18V DC takes approximately twice as long as with ± 9V DC due to the longer pause times.

Fig. 6: Wavecor WF182BD10 (9.0V DC)
Fig. 7: Faital 12PR320 (18.0V DC)

The following shows the effect of applying DC voltage to the voice coil on Re and the voice coil temperature. The measurement cycle is clearly visible in the progression.

Fig. 8: Wavecor WF182BD10

Fig. 9: Faital 12PR320

The picture of a measurement run also shows that the cone does not return to the zero position after each application of DC voltage, but rather an offset slowly builds up. Here's an evaluation example for the Faital 12PR320:
Fig. 10
Since only electrical measurements can be performed with the DATS LA, the cone excursion X-DC (red marked) must be calculated from the following data set:


Tab. 1

In the above-mentioned frequency range of 0.33 Hz, the following should apply in the linear range to a good approximation (Beranek & Mellow , Acoustics, page 286):

X(U) = BL(U) * U/Re(U) * Cms ( 0)

However, I still haven't figured out how Dayton DATS LA calculates the excursion in the nonlinear range. Unfortunately, my attempts at correction are only applicable to specific cases.

Below is a first measured example (Visaton AL130). The blue curve shows the DATS LA result for the excursion, while the red dashed curve shows the result calculated using the formula above. In the linear range, it fits quite well, as expected...
Fig. 11
Now let's do it all again with the excursion measured using a triangulation laser (dotted black line). The DATS result isn't quite identical, but it's pretty close.

Fig. 12
Is this the accuracy the system can offer in terms of displacement estimation? More on that later.

What impact do these inaccuracies in the excursion determination have on the parameter analysis? The following analysis is again from the Visaton AL130 (blue = DATS, red = laser-corrected). The linear excursion X(BL) is ± 6.1 mm for the DATS LA and ± 5.4 mm for the laser-corrected version.

Fig. 13
Since a full set of Klippel data is available for the AL130 used here, a direct comparison of the BL(x) analysis between the different measurement methods is a good option.

The following image shows the results of three - or four - measurement methods (red = Klippel, blue long dashed = DUMAX, green short dashed = DATS LA, black dotted = DATS LA laser-corrected). At least for the AL130, the results lie within a fairly narrow scatter band despite the very different measurement methods.

Fig. 14

To verify these results, two more examples are now shown ( Faital 12PR320, Wavecor WF182BD10).

Fig. 15: Faital 12PR320
Fig. 16: Wavecor WF182BD10


Obviously, the quality of the DATS LA excursion estimate in the first example cannot be transferred to other loudspeakers. Especially with the 12PR320, but also with the WF182BD10, there are significant discrepancies between the excursion estimate and the measurement. To illustrate the effects of these differences, the corresponding BL(x) diagrams are shown below (blue line = DATS LA, red line = laser-corrected).

Fig. 17: 12PR320

Fig. 18: WF182BD10

DATS LA shows ± 4.80 mm for the linear excursion X(BL,12PR320) and ± 5.95 mm for the laser-corrected variant, or ± 6.75 mm for X( BL,WF 182BD10) and ± 5.90 mm for the laser-corrected variant.

These deviations in the excursion determination naturally have an impact not only on the BL(x) curves but also on the other results such as Kms (x), Le(x), etc.

To further support the previous results, the X(BL) evaluation for all 22 measured loudspeakers is shown below:


Tab. 2

The difference between the DATS estimate and the laser-corrected measurement averages 16%, with a single standard deviation of ± 20%. This is probably not quite up to the quality standards of the Klippel Analyzer.

How do we evaluate these results?

Regardless of how relevant one considers the deviations to be, if one never knows how close the excursion calculated by DATS LA is to the measured reality without additional laser measuring equipment, there will always remain a feeling of uncertainty regarding the reliability of the measured data and this will inevitably lead to dissatisfaction in the long run.

Regards
Heinrich

This are my assumptions, and i am not an audio engineer.

This midrange is not designed for bass even if has lower fs. 30hz
The low fs come from the very lose suspension, believe it or not a loose suspension means eficiency, in a way, because it lowers the qes! Also making it good for ported, making it even more efficient.
Thats why they have such low qes qts.
This means that the coil doesnt have to be denser to achieve lower qes, instead the coil can have thinner wires to achieve a bigger bl (more total coil in the gap) better motor force controll. And with the loose suspension mechanical looses are very low.
This gives it very low distortions

Have a PPI A300 amp connected to the front speakers. I am noticing some slight static when the car is off. When the car is on, there is some slight wining as well. I ran both neg/pos 4 Gauge straight from the battery and have made good connections on both ends.

Can the amp itself be the issue? It seems the input is quite sensitive as well as I have a Xover 2XS in front of the input which I had to turn the gain almost all the way down on it or the volume is very loud at low volume levels on the head unit.

Thanks

Hiya,

Looking at SMD components to minimize area on PCBs, but kind of lost in what components to use.

In particular I want to add some caps/ferrites to stop noise/oscillations and wanted to know if I should go for PPS caps for the 10nF/100nF, and what to look for for ferrites. In through-hole components I am using MKP for the caps, ferrite beads on some wire and 150R tantanlum resistors but this takes up more space than I would like (even when using resistors/ferrites vertically.

Not sure what to look for in SMD equivalents. Anyone with experience in SMD components?

Working perfectly and in excellent cosmetic condition .

Bought to compare in my speakers

£60 + shipping ( I’m in the UK )

A strange occurrence for my TSE 11, I just finished the build after approx 8 hours or so, the source plays inside the chassis as if it has a speaker, it happens every time it is turned on, it also plays normally through speakers w/o any noise whatsoever, it is affected by the volume controls, which are Goldpoint, if they are at 50% then I cannot hear the inside speaker. Has anyone experienced this?

Who knows the exactly name of very high voltage booster capacitor manufacturer to the logo "db" (see attachement) ?

Hello, I'm a new user of this forum and want to introduce myself...

Just recently got back into "vintage" audio (I hate calling it that! it wasn't vintage when I was originally buying / building my set up, back in the 80's-90's). I've dug out my original gear from college and post college, and sadly, much of it is worse for wear. So I'm building a new set up mainly from facebook market place finds!

Anyway, I'm off to post about my BSR EQ-3000 which just quit on me 🙁 Want to see if anyone has any repair tips. See you over there!

Mab007

All electrolytic capacitors replaced with quality capacitors of equal value ( higher voltage ) including the large power supply capacitors.

Nichicon muse , Elma silmic , Kemet .

Din cables included

New thermal paste

£450 + shipping ( uk based )

Hello all
I have fallen in love with the Pearl Acoustic Sibelius but can't afford it.
Is it possible to clone it or build something similar? Please advice

24V dc to 300V dc capacitor charger with regulation (300V at 150mA at 78% efficiency): https://www.analog.com/media/en/technical-documentation/data-sheets/lt3751.pdf

So this not only can cope with managing inrush on a 2+mF 300V cap, it can also then regulate current output too. User configurable max charging limit too..

Seems it may be of interest to tube users.. now if only there was a larger regulated 500mA-1A version.

There’s also a coilcraft transformer specifically for this..

Hello everyone,

As mentioned in an old thread from years ago, running this program on newer Windows versions is nearly impossible. Additionally, the original installation files are no longer available on the official website and you can no longer purchase it.

After searching through my dad´s old computers, I found .iso files of the program and was able to make it work NO USB KEY needed. This has been tested and confirmed to work on:

• Windows 11 (64-bit)
• Windows 10 (64-bit)
• Windows 7 (32-bit & 64-bit)
• Windows XP

For proof, I recorded a short video demonstrating all three programs running on Windows 10 (64-bit) -> Video link

Installation Steps​

1. Download the "LinearX Leap5 + FilterShop.rar" uploaded to Google Drive. It contains two folders: "LEAP" and "FilterShop".
2. Extract the .rar file and move both folders to C:/Program Files/.

• Inside the "LEAP" folder:
  • LEAP_XVR.exe → Crossover Shop 5.1.0.334
  • LEAP_ENC.exe → Enclosure Shop 5.2.0.350
• Inside the "FilterShop" folder:
  • Fshop.exe → Filter Shop 3.4.0.808

You can create a shortcut for each executable by right-clicking the file and selecting "Create shortcut" to place it on the desktop.

Important: Fixing the "System Error: Number Decimal Symbol is Not a Decimal Point"​

Before opening the programs, it is necessary to change the decimal symbol in Windows from a comma (",") to a dot ("."), as the software requires this setting to function correctly.

Steps to change the decimal symbol:​

1. Open Control Panel.
2. Navigate to Clock and Region → Change date, time, or number formats.
3. Click Additional Settings.
4. Find the "Decimal symbol" field and change it from , (comma) to . (dot).

These steps apply to Windows 10, but the process is similar on other versions.

To simplify the process for everyone, I decided to upload only the necessary files—this way, installation is as easy as copying and pasting folders.

Greetings from Argentina!

Can anybody recommend surface mount resisters that are non-magnetic and very high quality, suitable for feedback circuits and high gain areas like phono stage ? I've got loads of choice from the basic to the ludicrous in through hole, but I don't see the same choice in SMD.

First ones I'm looking for are to bias op amp into class A, currently have through hole resisters soldered into an 8 pin socket, which despite being small, are still too large and I thought SMD would be a good replacement.

I've read a lot of people denigrating SMD for audio, but there must be some devices which are suitable, low inductance, low noise, non-magnetic etc. All DACs and streamers use SMD and some of the DACs I've heard sound very fine indeed, I just need to understand what's available.

Thanks

New (NOS) Analog Devices AD745KN FET Opamp from a bonafide USA distributor. 8DIP package. 1997 datecode. Still an excellent performing opamp for MM phono preamps or ADCOM GFP-565 preamplifier upgrade (with appropriate capacitor and resistor changes). Selling off old shop inventory. 34 available. USA sale only. No international shipping is available. Send pm if interested.

I'm sharing a slightly different kind of post here, hoping it will find its way to the right people. I’d truly appreciate any shares in relevant places.With great sadness, my family and I recently said goodbye to my father after his battle with cancer. My dad was a very special person, and there’s so much I could say about him—but in the context of this group, there’s one thing in particular that stands out: his deep passion for sound and audio.

Over many years, he acquired an impressive amount of knowledge, technical skill, and understanding, which he used to restore, upgrade, and build a variety of equipment—from amplifiers to speakers, turntables, and more. Before he became ill, he had started working on several projects, but sadly had to stop midway, and now they sit unfinished with an uncertain future.

I’ll be the first to admit—I don’t have the expertise my father had. What I do share with him is a deep love for music, which was one of the strongest bonds between us. But unfortunately, he didn’t pass down his technical skills to me.I’m posting here because I feel that my father left me with a mission—his legacy, if you will. And I’ve made it my goal to try and complete the work he couldn’t finish himself.

I’m looking for a mentor, a guide—someone who can help me understand where to even begin with these projects that meant so much to my father. I’ve attached some photos of what he left behind, in the hope that someone might see the value in this and, out of love for this beautiful world of stereo and sound, help me breathe life back into a dream that’s been paused.

(Just a note: all the items shown in the photos, except for the QUAD speakers, are unfinished projects. The QUADs are functional—I included them to give a sense of the level of investment and dedication my father had for this craft.)

*A pair of Quad electrostatic speakers — rebuilt and fully functional



*Sony's VFET R0 Diy Kit


*JVC TT-101

Hello all, I found this forum after looking into a modification project for my stereo. I want learn more and ask questions so here I am no longer lurking.

Hello everyone,

Following the sudden death of my Sherwood R965, which I was unable to repair, I decided to build an ESP P101 Mosfets amplifier.
I'm going to start with two channels, and will probably add three more later.

So I bought a set of boards from Rod, including:

2x P101c Power amplifier
1x P39c Soft start
1x P33b Loudspeaker protection
2x P245a Mosfet relay

I will reuse the Sherwood R965's case and power supply (600W, +/-56V, 2x27000 uF).

Regarding the P245a (mosfet relay), Rod recommends several references, but I already have components that seem suitable, although I don't have the expertise to be certain.

The mosfets I have are : CSD19536KCS from Texas Instruments

Will they be suitable for this application ?

Regarding the P101c, Rod mainly recommends the ECX10N20 / ECX10P20 references, but these components are difficult to find and obsolete according to the manufacturer, who instead recommends the ECX10N20-W6 / ECX10P20-W6 models.

Again, I assume they are suitable, but I want to be sure...

Thanks in advance to anyone who tries to help me.

It seems that most DVMs that I have used don't have much resistance accuracy below the 10 ohm mark. Is there anything that is accurate at that level? From 1 or 2 ohms to 10 ohms.

I would be ok with a straight ohmmeter with no other functions

So, you have a burning desire to measure harmonic distortion and other audio parameters but don't have $40k burning a holes in your pockets so you can buy an APx555B. I have news for you: There are cheaper options.

I just finished testing three such options:

• QuantAsylum QA403 Audio Analyzer ($600)
• Focusrite Scarlett 2i2, 4th Generation ($200)
• Focusrite Scarlett Solo, 3rd Generation (Refurbished from Focusrite: $80)

The results will probably surprise you. For example, I was surprised that the third Generation Solo performed better than the fourth generation 2i2 with single-ended input. I also think you get incredible bang for your buck with the QA403.

Unfortunately ultrasonic noise limits the maximum usable frequency for THD+N vs frequency sweeps on the Scarlett sound cards. Basically the noise renders the 192 kHz sampling rate useless for audio measurements. 96 kHz works fine, but then you're limited to a maximum test frequency of 15 kHz if you want two harmonics (H2 and H3) included in the THD measurement.

I've included the loopback plots below. I have tons more measurements available here: https://neurochrome.com/pages/measuring-distortion-on-the-cheap

I also yap about it here:
Login to view embedded media
QA403:



Scarlett 2i2 (4th Gen):



Scarlett Solo (3rd Gen):



Tom

Good day
Dear gents
After few months of work I make the Nait2 main board to aluminium case

Hey everyone, I’ve been sketching out a 3-way speaker build and wanted to get your thoughts on mixing pro audio components with hi-fi ones in a single design.

Here's what I’m thinking:

• Highs: Compression driver + waveguide (pro audio style)
• Mids: SICA 8 Fe 2.5cp (8" pro midrange)
• Lows: Instead of a typical pro sub, I’m considering the Peerless by Tymphany XXLS-P830845 (12" Nomex Cone Subwoofer, 8 Ohm), which is more of a hi-fi driver with a lower sensitivity (~87dB).

My question is about making the low end "keep up" with the rest of the system. If I run two of the Peerless subs in parallel, would I effectively gain:

• +3dB from doubling the driver count
• +3dB from halving the impedance (going from 8Ω to 4Ω load)

Bringing the system sensitivity from ~87dB to ~93–94dB? Would that be enough to balance well with the higher-sensitivity pro drivers, or am I missing something here? I know there’s more to it than just raw dB—like dynamic response, damping, and matching tonal characteristics—but I’m curious if this is a path worth pursuing or fundamentally mismatched.

Appreciate any insight or real-world experience anyone can share—thanks!

Hello,

i have a bluetooth receiver with the QCC3040 onboard. I already got to unlock it and a connection over bluetooth and did a backup with Nvs.

I tried to change the name with the ConfigApp, but it doesn't work - i can't transfer with error and after that, the QCC is dead. I have to burn the backup with Nvs.

The QCCTool doesn't get a connection.

Actually I have to power up the QCC3040 by long-press the SYS_CTRL.
My first goal is, that the QCC3040 power up automatically when voltage is applied. Can i do this simple by changing a parameter with a program?

Second goal would be to change the name - maybe it is only possible by SPI?

Thank you very much for your support.

I'm using 4" full-range whizzer cone speakers: Boston Acoustics 704. They operate normally. No lack of treble. However, one day, I found the NOS tweeters of the same series with these full-range; Boston Acoustics 700, are being sold. I think what if I buy and add them to the 4" full-ranges.

Of course, the HPF for the tweeter is required. But, how about LPF for the full-range, isn't it required?

If so, the x-over point might be set at around 4-5kHz (no problem). But, if not, which means running the full-range (closed) to 20kHz as usual and assigning somewhere upper frequency for the tweeters to handle, then, what frequency should be set for HPF of tweeters?

PS. I have a DSP in my system so I can actively control x-over.



As can be seen in the diagram, there are green labeled (X)Hz. They are meant that there's still no information about crossover frequencies on them.

The cone drive units will be used are full-range 4" Boston Acoustics 704 speakers, see pictures attached for specifications. Here is the question: what frequency should be applied to the 4" full-range driver as a high-pass crossover and the 6" mid-bass drivers for a low-pass crossover?

Love to hear everyone's thoughts. Happy weekend!

Hi ive been on here for years, enjoying fullrange driver and turntable topics. My old email account expired and can no longer access it. Hence the new account here. Thanks!

Hey,

i'm Andreas from Germany. I try to make first steps in programming Bluetooth Chips from Qualcomm and hope i can find some help and informations here.

At the other hand i try to repair old amplifiers, when i get one.