I have read some threads and some some searching around but I cannot find what I'm looking for: some way to play my ripped CD's from the NAS. But...

• no dependency on apple, google, sonos,... Something that doesn't need an account or that stops playing at the next update because it doesn't like my wallpaper
• working with .wav files and .m3u playlists
• not needing an app but some dedicated hardware is ok (an app would probably mean a hard dependency on apple or google anyway)
• cabled ethernet connection, the house is wired thank you very much. If there is wifi it can be disabled.
• reading from a usb hd is ok
• bluetooth is a not wanted, only admitted if it can be disabled
• ability do disable anything I don't need or like: upnp, bonjour, ...
• I'd like a digital out on coax but optical is ok, analog if nothing else volume control etc isn't needed but if it is present and can be disabled I can live with it
• should boot faster than my laptop (mine, not that from the office, that one takes 10 minutes on a good day (30 on an update day))
• if it can play internet radio that is a bonus but not a requirement
• don't need fancy displays etc.

Hi, just wondered if the above were interchangeable?
Thanks.

Clearance sale! My drawers are getting too full and I have a SissySIT P still to build so I'm letting this one go. All components have been used as a working amplifier but I deconstructed it to use them in a new enclosure.

So what's included:

1. THF51 SIT's 2x
2. SissySIT R3 boards (excl. signal trafo's)
3. 400VA 2x18v trafo (220v) audiograde trafo from Toroidy
4. First watt PSU (universal power supply pcb from diyaudio store)
5.Chassis mount diode bridges
6. Frankenchassis, so Dissipante 4U 300mm but in a smaller formfactor, no front plate included
7. Loudspeaker terminals and rca-connectors
8. 220v power outlet connector with fuse holder

This package includes everything to get it up and running except for wiring and the signal transformers (Edcor/Cinemag/Jensen)

Asking EUR 400 for everything excl. shipping.

Best,

Robin

Hi guys,

Does anybody has schematic diagram and / or manual for Audiolab 8000SX? Thanks in advance, Peter

Hi, I bought a dead Vermon ER9 and I'm trying to work out the PSU voltages. If anybody has one could they kindly measure what the voltages are eminating from the PSU. I've got 20 volts AC going in - the transformer seems to be working OK, but nothing coming out of the PSU. Does anyone know that the voltages should be? I intend to build a new PSU to hopefully bring the machine back to life. There's no info on the schematic I have.
The wires are as follow: Wires from left to right
Orange from transformer, green???
Black
NC
Yellow
Red
Brown
Orange from transformer

Inspired by Isaac Moore's speaker concept on reddit using the gyroid infill as damping and locking, I have designed my own desktop 3d printed omnidirectional speakers. I would like to hear the Duevel Planets, but as I live in South America it's not that easy to have access to high end listening rooms.



Configuration used for the printing:
0.6mm nozzle
0.8mm wall x 4 (3.2mm total wall)
8% Gyroid infill
10 botton and top layers (2mm)
Fuzzy skin to finish



The printing time was about 25 hours per cabinet, and there's no extra damping material inside, only the gyroid infill which acts as infill as well as interlocking the structure. I can feel a little vibration from the walls when I really crank up the volume, but this does not happens on listening levels.

It's a bass reflex design, using the Tangband W3-2141 driver in an upfiring position, the port is downfirering and designed with the speaker, flanged in both ends and tuned to 70Hz. After a lot of 3D printed diffuser designs, this is the one that worked for me and it's a glass ball used in pet water fountains on a prited support that rests on the original fixed driver's phase plug.

I like what the omnidirectional design can do with the soundstage, the speakers really desapears. There's another one on the right side of the desk, nearfield listening as my ears are like 80cm from the speakers all the time in a 30º angle from the top. I have also designed and printed the magnetic levitating feed, using the repulsion of 2 magnet as isolators. This really helps to keep my desk from vibrating:




I'm currently using it as a 2.1 setup, with a Thonet & Vander subwoofer from 60Hz below that sits under my desk, amplified by a dedicated ebay amp with active variable crossover and lowpass filter. I use some EQ to push up the top end with a shelf filter about 6dB @9kHz.

Completing the setup, I have an ifi UNO DAC and the amp is a chinese integrated tube amp using EL84, with 3+3W single ended with RTC5654 on pre amp stage and 6P15P-EV on the power, same as the Decware Zen Triode amp recomends.

For now, I believe I have achieved what I was looking for, as I can listen to my preferred music all day long while working on the computer.

English is not my first language, sorry. The speakers were printed using 800g of PLA each.

Hi, I found this site while searching for the audiolab 8000sx

Hey there,
Id like to find a way to test transistors for noise. I want to test a bunch of the same type in order to find the lowest noise ones. I do have a peak atlas that does everything else just fine.
Now the first idea im having is to build some kind of circuit that puts the transistor in a prominent position, socket that and then i could maybe use my audio precision analyzer to test for noise? Is this a valid idea? If so, does anyone know a circuit that will work for this?

Thanks

Some time ago my friend Joe asked me, if I would like and design an AMP with 2 pairs of TO-3 output transistors.

Both, Joe and I, have a couple of MJ2119x transistors at hand, which are worth to be used.

I studied some of the DIY - AMPs in this forum and felt, that Michael Bittner's SYMASYM would be the best match to do the job.

I transferred his SYMASYM version 5.3 into EAGLE, did not change anything in the frontend, but added the pairs of TO-3 in the backend.
DADOD (thank you very much!) simulated the resulting AMP in LTSpice: the results look perfect!

I have attached the schematics as a PDF-file.

After finishing the layout, I had some space left on the bottom right and left side of the PCB and implemented a standard capacitor-multiplier
for the frontend there.

This is the resulting layout:



The red lines indicate tracks, that are running on the top side.
The TO-3s will be mounted on ALU-brackets.
The size of the PCB is 150 x 100mm.

Joe and I want the PCBs to be etched professionally, having the same quality as the PCBs, that I offered in my group-buys
for Carlos Mergulhao's DX Blame (see the picture below).



Since the SYMASYM, the backend and the capacitor-multipliers are proven circuits, we won't do prototyping.

In order to get a decent (about 13€ per PCB) price from the etching company, I must order at least 10 PCBs.

Maybe some of you like this design (SYMASYM with TO-3) and join the party.
I am sure, it will give you a big bang for your bucks.
Take a careful look at the schematics then and tell me, if I shall change anything.

Best regards - Rudi_Ratlos

Hello, everyone.

I'm wondering if this topic has been discussed before. A search for blowtorch power amp only gave me a zillion results about the line stage. Every once in a while, I revisit the idea about a F5X that utilizes super symmetry. That topic was discussed a little, but I don't think a true solution was ever found. I finally decided to put an idea down on paper to see what you all think.

Basically, a blowtorch line stage with complimentary voltage follower power stages on each end combined with the low impedance global feedback implemented in the F5.



While I wouldn't consider this truly an F5 iteration, I do believe it is in the same spirit. I also believe this satisfies the requirements for super symmetry.

Thoughts?

Technical specifications:

Inputs: Digital USB audio and Analog stereo.
Controls: Volume, Mute, Balance, Treble and Bass, SuperBass algorithm.
Output: Analog Stereo.

In the assembly we use USB audio transport Reflex and DSP processor ADAU1701. Reflex works in Slave mode and is clocked by ADAU1701. ADAU1701 in Master mode.
I described the Reflex transport earlier. You can see it.



The module with ADAU1701 is a board with a DSP ADAU1701 and two generators.





The first generator with a frequency of 12.288 MHz, and the second with a frequency of 11.2896 MHz. The scheme is like this:



The PCB can be viewed and ordered from the KiCad project.

First, an audio project is made in SigmaStudio.


At the input there is a selector that switches inputs: Analog and Digital USB. Behind it there is a volume control and a balance control. Next are the LF and HF tone controls. Before the output there is the SuperBass algorithm. For each sampling frequency there are projects that are identical in scheme, but different in register settings depending on the sampling frequency.
Be careful with the register settings if you want to change my project. They must remain unchanged for each sampling frequency.
Transport Reflex Depending on the sampling frequency on the I2C bus, it rebuilds the ADAU170 registers, switches the generators installed on the ADAU1701 board and loads the required project into the ADAU. Everything is done automatically.
The control elements (potentiometers, buttons and LEDs) are connected to the GPIO outputs on the Reflex according to the ChipStudio diagram. You can assign any others.



Download ChipStudio software, unpack it on your PC. Open the combo project in ChipStudio. Put jumper 12 on Reflex, connect Reflex to the PC, load the combo project into it, remove jumper 12 and everything works for you.

The connection block diagram is as follows:

Please pay attention to the installation of jumpers.

I have a front panel from a DSP Machine.


SigmaStudio Projects

Combo project for ChipStudio

Firmware for Reflex

KiCad project

ChipStudio soft

For now, you can order boards from the KiCad project and make PCBs with adau1701 and Reflex yourself. They are very simple.

I will answer any questions.

Follow the headlines ChipDipDAC did it, so can you. I will show examples of how to do it.

The next project is DSP Machine 3. Hi-Res Streamer (ADAU1452+AD1934) for Raspberry Pi (driver & overlay ChipDip DAC)

Enjoy!

Hi everyone,

I'm Joshua from China.

I just followed Miro1360's guide and built the AD1862 DAC.

Hi,

I'm building a balanced audio mute circuit. Till now I tried using a latching DPDT relay that when activated shorts Pins 2 and 3 together to Pin 1. I used a latching relay because it is supposed to have less mechanical noise. However I can hear a tiny mechanical click when unmuting the audio (this is more evident when no audio is present). For reference the circuit is the top one in this link.

Thus I tried building something like this where I connected two optocouplers outputs to both pins 2 and 3. When activating the optocoupler this shorts the signal to Pin 1. This worked to a certain extent, because instead I am getting very low volume. Any idea why this is happening? Shouldn't I get a complete mute?

Thanks

One difference is that you will need a mahusive plinth - as fitted to my Goldring '88' - to accommodate its 3012 arm. I can imagine a few slight advantages and disadvantages but never heard an informed explanation.

Yes, not all arms are 12 or 9 but they were common lengths.

I'm looking for some help from any Midi/SysEx guru's here.

Is there any way to retrieve the current preset from the Behringer DEQ2496?
Better yet, fetch just the preset number?

Any help would be greatly appreciated. TIA

For the last month I have been playing around with front horn loading an 8" planar mid driver from GRS.
https://www.parts-express.com/GRS-PT6825-8-8-Planar-Mid-Tweeter-8-Ohm-272-126?quantity=1

The idea was to flatten the response. It was quite erratic stock. Too erratic for my skill level to beat into submission.

I knew I could load it and flatten it, I just didn't know how. I started by just making all sorts of horns. I think I started with 6 different designs. Traditional, traditional with phase plugs, throated horns, etc. With this I found a pattern but knew I need to figure out Horn Resp. So I did.

Horn Resp has a hell of a learning curve. All the sim really shows you is the power. A planar mid has no specs that load into HornResp. I first had to find a driver whose specs reflect that of the planar. Not so easy. An excercise in pattern finding. I succeeded in finding a 4" Tang Band whose specs made do as a very good replacement for the planar.

I printed out 4 more horns to try. Now I had to find a pattern between the power response and the actual increase in SPL to frequency range of the driver. I found this with graphs. Its around 3.1 Db but its not that easy. More of a dark art as it does change throughout the frequency range.

I'll show some data here but the best performing horn is quite large, and quite wide. Too wide and long for its intended application which was my office monitor. Its length also causes issue crossing it since you have to add in the X offset. I could add the woofer far back behind the horn and get away with it but the tweeter would be a problem. I am unsure at this point how to create a notch filter that would knock down the entire range from 5k-15k hz. If someone knows how, let me know please.

What is most interesting to me about the horn loading is you can increase the lower range AND reduce distortion at the same time. You could EQ this driver up to make it respond flat but would do nothing for the drastically rising distortion. Horn loading it increases the SPL and decreases the distortion at once increasing its range dramatically.

I'm still working out how to cross this with some other drivers. This has very high sensitivity so pairing it with a woofer that hits low generally dictates a very large resistor.

Alright, now I'll add all the data and models.

Best horn is here: I call it Big Grey

Is there any hope of using the mfr models in linear mode for ZVN and ZVP4525G? They simulate way too well to be true..

I suspect that I may be asking a stupid question but here goes. I have had the above gadget for some years but always wondered if there was any benefit of matching another Dac with it by using the 75 Ohm Word Clock input to receive the signal from the Dac.

Is this deigned to match the clock in the Dac to the Behringer clock for better transmission?

Recently I downgraded my system to make/save some money, and one of the things I tried was using a few cheap old DVD players, with a coax digital output, as CD transports.

For a number of reasons, it wasn't working out, one of them those things being really noisy during operation.
That and they don't sound so good.

However, I've always been a huge fan of the Shigaclone projects, and similar diy CD players.
Also, the player I'd been using for many years before the change, was a 47 Labs Shigaraki.

So naturally, I took one of the DVD players apart, ripped out all of the tray mechanism bits, mounted the laser mechanism on a piece of wood, and it worked without any issues.

I also ripped out and used the existing magnetic puck of the player - which ist being used in the majority of CD players - fixed the little lever thingy into place that tells the player if the tray is closed or open - and I had a perfectly fine top loading CD transport.

Minus most of the vibrations/noise and other possible problems that are related to the tray itself, and the moving up/down of the laser mechanism when the tray is being opened or closed.
All the buttons and the remote were working fine too.
Until I blew up the PSU, but let's not talk about that.

So why aren't there more top loading players or transports?
You have to pay a lot of money to get one of those, as most of them are in the high-end segment of the audio market.

Yet it eliminates a lot of the possible issues, actually saves money in production, and you have to get off the chair to change the CD anyways.
Granted, there needs to be a little bit of extra space above the player, but that's about it.

Now I own a used Onkyo 7030, which is very nice; but I can't stop wondering why the thing is so big, and what it would be like if there was just a little drawer or lid on top of the laser mechanism, instead of the tray, which is likely to create issues one day.

Well, sorry if it was a bit of a rant; but I'm curious what your thoughts are, and if perhaps some of you did a simple conversion from tray or slot loading to top laoding.
The projects I've seen, whether it's upgrading a player or building one more or less from scratch, don't seem to cover a relatively simple mod like that.

miniDSP Flex HT

Only 3 weeks old.
Mint condition
Retail price: US$ 599

miniDSP has a no return policy or I would have sent it back.
Everything works perfectly, just the TV I have doesn't have eARC HDMI ;-)

$500 + shipping

Hi all,

I'm new to this forum so not sure if this is the sort of thing that interests anyone here.

I've recently repaired a Behringer DEQ2496 due to a failed power supply (bad caps and a failed TOP245 switching controller) and while I had it in pieces I decided to finally write a program to communicate with it over MIDI as I had been meaning to do for many years.

It turned out that Behringer's SysEx document for the DEQ2496 is mostly wrong when it comes to the firmware, so it look a bit of reverse engineering and disassembly but I finally got the unit to accept messages from me:



The code is written in NodeJS and is available on GitHub if anyone is interested. It's still incomplete at the moment but I hope to add a few more features to it. Contributions are welcome if anyone wants to add support for other devices!

It's been a bit of an adventure getting this far, figuring out all the undocumented things. The data blocks you send to the device are encrypted with the string "TZ'04" (I'm guessing the initials of one of the developers), and the 7/8 coding and "CRC" algorithms mentioned in the SysEx manual aren't widely used or documented anywhere. But after a few days of trial and error I got it to work!

There are hints in the firmware that there might be a few undocumented SysEx functions (mostly technical) and there seems to be a hidden hardware test mode that I'd like to figure out how to activate, just out of curiosity. Apparently (from the messages I found) it's got something to do with adjusting the VR1 potentiometer on the main board.

My goal is to see if I can get the unit to run my own firmware, just for the fun of it. I could never hope to reproduce the functionality of the official firmware, but it always struck me that the device seems under utilised, with all those extra push knobs and buttons that duplicate functionality. Perhaps if I get all the pieces in place, someone else might end up creating their own firmware for it. Apparently there are ports of Linux that run on the Blackfin processors used by the device, so although it would be completely pointless, part of me wants to get Linux to boot on it just to see if it can be done 😀 (might be a bit tight though as it only has 2MB of RAM.)

Let me know if anyone is interested in this sort of thing and I'll post updates if I have any successes.

Hi,

My name is Phil.
I am an audio engineer / mixing engineer in Las Vegas.
I have reasonable electronic repair abilities but can always use a little help!

That is why I came here and I am glad to have found this community.

Hope I can also help others someday 🙂

Does anyone have a Balanced MuStage Tube Headphone Amp schematic that you can share?

Thanks Ben

Hi there,

I'm looking to buy a pair of Raytheon 45 four pillar tube to try with my DIY SE 45. If you have this for sell, please send me a message with picture, measures and asking price.

Thanks!

Sébastien

Hello guy's I am Wayne (Novais), from Angola-Africa, I am an electronic technician, I repair radios, tv's and power amplifier's and all domestic electronic devices, I've doing it for 30 years ago, I am 43 years, father of six son's I live with them and I am a single man. Thanks for your reading...

Hello everyone. I am a new audio player for 1 year. Nice to meet everyone.
I own a Gas Thaedra 2 preamp. It originally runs on 120v but I accidentally plugged it into 220v. I hope someone on the forum with experience can please let me know if it can be repaired. Thanks!

Good day everyone. I am a novice DIYer, and I need help choosing components for my builds.

I built 300b monoblocks, a tube preamplifier, and two dacs from kits entirely point to point on fiberglass boards.

looking forward to put together some solid state devices in the near future.

Hello

im researching some power supply options the last couple of days and came across that in the old days pro audio pedals and stuff like the DIY studio headphone amplifier HC1 were or still are run on 9V block batteries and were playing with the idea of building some kind of constant powered 9V block battery replacement with 2s lipo cells at first... my research made me curious about "lithium ion capacitors", i heared now a few times they are not worth it but if you look at the specs they really combine lithium ion and supercap technology

• fairly low ESR, high current capability
• can be quite often recharged in comparison to batteries (2000 vs 100k)
• more safe than lithium ion batterys
• supercaps in 500F size are alot bigger than 500F lithium caps
• 500F lithium cap costs about 5 euro, i think high quality 500F supercaps are more like 25-40euro

since im really trying to integrate both, battery and supercaps, this might be a costeffective solution for getting the best out of both worlds


so far i plan to:

• 9V unregulated pure battery isolated power supply with only the lithium caps (and maybe some protection circuitry) connected to the load
• 2 banks of lithium caps, one can be charged or be on hold and the other is in use
• lithium caps have a range of around 3V to 4.2V, with nominal 3.8V, you can extend life with not going much above 3.8V

so one could actually do:
2x 3.7V = 7.4V ( to 6.6V ) as 7V supply
2x 4.2V = 8.4V ( to 7.6V ) as 9V block battery replacement / 8V supply
5/3.3V via regulator
- 2x 1000F banks should be enough for low power applications, i rather use one more supply and we are already in the 50 mOhm ESR region (so basicly like an (good) relay contact)
around 2Ah for 8.4V / 1000F

• i still havent found the perfect charging/balancing chip combo here, one solution is switching the caps from serial to parellel for charging, no balancing needed i think...
• power monitoring and a mcu is somewhat i still question (because of "minimal design") but it would be cool to have

did anyone experiment with lithium caps here or compared them? and ideas/suggestions?

Hi ! Can I increase the quiss current for this Class B amp into Class AB , would that improve the sound? , or anything at all ? or not if there is no cross-over distortion to begin with ?.
It's a Toshiba SC-M15 , Input and pre-driver stages are in Class A, output in Class B; both stages are fed from two different trafo windings.
I was thinking : Changing R653 with a bigger value pot might do it . Run it at 50 - 70 mA , maybe more , thermally I don't think it would be a problem , the whole case it's a heatsink, ( Q613 , Q615 , might need heatsinking ? )
Why did they bias it into Class B and not Class AB in the first place !?.
- Bruno.

I just bought this mini dac based on this CS chip which seems to be a good (cheap) alternative... 🧐
Have any of you tried it yet?
Audio DAC CS43131: https://fr.aliexpress.com/item/1005...st_main.9.110a5e5bKJhm4H&gatewayAdapt=glo2fra

Hey Guys,

While I'm repairing (hopefully I'm gonna be successful) my Tandberg 3026A MOSFET Power Amp (was their TOTL at the time, their engineers and people involved went on to work at/found Electrocompaniet, Dynamic Precision, Hegel) I'm also doing a 2 way speaker modification that I am kind of taking a gamble on, because I'm not really 100% sure how these things work.

I have JBL Studio 580 that are budget, but pretty interesting speakers, however their horn driver crossed over at 1500 Hz really lacked definition or beauty and just didn't do justice to my amplification. However I really really like the titanium tweeter in the new JBL classic line (L100 and L82 classic) and since I know that L82 crosses over at 1700 Hz I thought I'd give it a shot. I tried connecting it directly to my amp with DSP and it's pretty much linear from 1500 Hz and the same cannot be said about the horn driver that was originally in the speaker. So now I just want to create a third order filter (like is also found on the bass drivers in my 580 or at least I think it's third order based on my limited understanding) and put very simple third order filter on the titanium tweeter. I already tried integrating it with DSP and it works beautifully. Now I just need passive crossover and I'd like to utilize the components that are already present in the high pass filter. The level I will adjust easily with a resistors, but since the original horn driver had a high frequency roll off and some other irregularities, the high pass filter doesn't work with my titanium tweeter. Could somebody point me in the right direction in terms of what should I remove from this circuit to make it the most basic third order filter, what should I add?

So yeah, looking for advice that a novice like me could take action on in terms of modifying and simplifying this crossover, namely the high pass filter. Many thanks 🙏🏻

Don't underestamte this humble small system
I have been listening for 5 hours in my patio...love it...

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finally the Stereo light on

Hi there. I am from Germany and started my DIY journey two years ago. I started with building two speaker sets:

• Le Petit 2.0
• Monitor #M1 … rumored to be the best selling DIY speakers of the past 20 years.

Now it is time to start with a DAC project: Lampucera Lampizator I and 2.0 (iiwi youtube channel)
See you around
Sebastian

Hello All,

Been lurking here for the past 2 weeks, thought I'd jump in and ask some questions.

I am running a low powered Bottlehead Sex SET amp, and jumped into the full range speaker world with a used pair of Blumenstein Orcas about a year ago. Fell in love with the SET plus single driver sound. Now I'm curious to start building my own enclosures and explore a bit.

Thanks for all the wealth of knowledge on the forum!

Noah

ScanSpeak D2905/930000 Tweeter
Used but tests fine. Bought but didn't use.
Shipping USPS at actual.
Paypal F&F or G&S (add 3%)

FS: FOCAL Drivers 7L-011DB
These are the metal basket Focals, not the later plastic baskets. They are in excellent condition.
Got them in a DIY box I bought years ago and they've been in the closet since then. Surrounds are in excellent condition.
I found what I think is the data sheet for them.
If you need shipping, it's coming from 03862, USPS preferred. PayPal F&F or G&S (add 3%).

Thanks, Dan Derby

My 10 years old McCormack DNA 0.5 amp (regular not upgraded) sends a really loud buzz to the speakers the moment it's turned on. After that, the power indicator led goes from red to green and everything seems to be working. The loud buzz happens even when nothing is connected to the input.

Mr. McCormack was very nice to provide me with a schematic of the amp. The problem is my electronic experience is only limit to kit building and such.

So I send my amp to a local shop. They told me the problem is caused by a surface mount chip so it can not be repaired. The total cost for replacing the main board is close to $400! Maybe I am wrong but I didn't see any surface mount chip in the amp when I open the cover. Plus, I have replaced surface mount chip myself before so I just dropped the diagnostic cost and walked out of the door.

Can anyone help me identify the capacitors and transistors to check? Due to potential copyright issue I am not sure I should post the diagram here, but maybe through email? Thanks.

TY

I've just been given a Denon M35DAB which is working well however when switching on from cold the display lights and cd's will load and appear to play but there is no sound. After a minute or two a relay which I'm assuming is a protection relay will start clicking on and off and after about 10 seconds of morse code sounding clicks the system works fine. I originally tried this with 4 ohm speakers then realised it needed a minimum 6 ohm, same problem with both. The problem was there before connecting speakers so don't think they're the cause. Both pairs are fine when connected elsewhere. Is this a known fault with solution? If not any suggestion where to start?

So, perhaps too simple But indulge me.

Building F4’s to bridge as monoblocks. Do I merely tie the inputs of the R + L channels together, and similarly tie the outputs as well?

Thanks

I've got a Marantz PM7200 which has a class A mode, which is most likely just a high biased class A/B, but it definitely sounds great with vocal and instrumental music. The sound is warm and lively and it feels like the instruments are real and in front of me when listening. I'm planning to get rid of my amp due to lack of space/use for now, then in the future I want to buy an amp that sounds at least this good. I don't want to regret my decision, so do you recommend to still keep it or will I easily find better and probably true class A that sounds even better in the £500 - £1500 price range?

One pair of Fostex FE167E 'Full Range' Speaker Drivers.

I bought these a few years ago and planned to use them in an Open Baffle project - it never happened and as I've just purchased a pair of Lii Audio Fast-10S speakers for my next project these are now surplus to requirements.

They are in good used condition - please see the pictures below. For the time I've owned them they've been sitting on a shelf. I connected them up last weekend and they work and sound fine - could maybe benefit from some 'running-in' as they've been sat dormant for some time.

£50 plus shipping and PayPal fee at cost. Send me a PM if you're interested.

Anyone have any info on the old SCS, Sound Code System amplifiers. i know they were Mosfet but i am looking for any kind of info on power ratings etc for the 2350 models.



Zc

For sale is 32 pcs of original Rubycon USR 4700uF/63V brand new capacitors. It is 25mm diameter so it fits on PCBs that have large diameter or to repair existing audio amplifier psu that have 25mm diameter on PCB diameter....it is small and high ripple current with low esr.

Price for each is USD$5,00 plus shipping cost.

Price for all 32pcs is USD$160,00 free shipping.

Interested members send me PM so that i can get shipping address and payment accepted is by paypal.

Hi, I'm looking for a BOM for the Aleph J.
Also, any recommendations for a 230v 400VA transformer for it. Preferably UK based.

Thanks

Just checking if anyone has used pair available and willing to sell.
Would be used in a MTM speaker.

I know they are available as new but checking the options if used are available at this time.

BR, Sami

Hi, First of all a word of caution , if you attempt this you may well wreck your pickup/player, if anyone attempts this proceed with caution. O.K. That said and done this is what I did.
My Micromega Stage player began to skip a few months ago, and the main problems (dried out grease) are well known and I will not go into that here. The pickup is a replacement Japanese unit fitted about three years ago, and the quality is much better than anything I have seen since. Anyway after stripping the unit and washing the gears/rack in isopropanol and using a special plastics grease to reassemble I wondered if it would be possible to remove the lens assembly and clean both the underside of the lens and also the prism or "turning mirror" beneath. The lens is supported on nylon suspension arms and these clip into the lens carrier itself. Using tweezers it is possible to gently release one side first, then very carefully lift the lens up so that there is sufficient space to release the other side. If you can support the pickup in a a small desktop vice so much the better. The lens carrier can then be carefully turned over and laid on the pickup. Be very careful as the wires to the lens will break easily. You can now clean the underside of the lens and mirror below. Next reassemble. Hopefully job done. The next step I did not try for real but suspect it would work. The laser diode is glued into pickup with epoxy. If you firmly grasp the P.C.B. of the laser diode with pliers (sounds horrific but is not) and twist gently the glue cracks cleanly and in such a way that the diode can be refitted just about exactly as it came out. This enables you to clean the front face of diode and photodetector. Why this obsession with cleaning the optics, well take a wine glass clean it and put it in a clean cupboard or similar and leave it there for a few years. Bet it's not nice and shiny then. I believe more pickups are replaced for these reasons than simply because the laser has failed. I have not had a single "skip" since and thats in a few hundred playing hours, both cd and cdr. All the CDM12.xxx are similar and the optics are simple, a combined laserdiode and photodetector, a prism and the lens. Please remember if you want to try this that you stand a good chance of damaging the pickup, but if you are going to replace it anyway probably nothing to lose in having a go.
Regards Karl

Stumped on a repair of an xti4000. Original problem was low output level. Found a shorted cap in the power supply, C47. Replaced and rail voltages looked good. Sounded normal, sent out for use. Came back with low volume report, though initial report was normal operation. Looked deeper, transistors test ok, no major component malfunction apparent. Traced rail voltages to output transisitors and it seems to be lost along the way, on + and - sides. Seeing 30v +/-. That comes from the other power supply tap LR1+/- though so it seems the 140 volts is gone after it enters the power amp section. Got lost going in circles, pretty complicated amp, I am pretty seasoned in repairs but this one is about to be a paperweight if I cant get it figured soon.

Schematic Here, pages 150-154
Crown XTi 4000 file: XTi Series Service Manual original (davidcab) - Audiofanzine

I have a ton of voltage readings, spent hours pouring over the schematics and testing testing to no avail. Any and all advice and help would be so dearly appreciated.

I have a feeling it is some kind of muting circuit or microchip issue?

Thanks, JOSH

I have 2 pairs (4 units) of ADS S10 10” subwoofer drivers. I cannot decide which type of enclosures should be used since the manual suggests both closed enclosure and infinite baffle types. But if I choose closed enclosure, only two of them can be used because of limited trunk space. While the IB allows to install all 4 units—under the rear parcel shelf of the ‘83 380SEL. So, regarding the manual attached, please advise me which way is better and should go for.

I'm looking for a Quasimodo V4 PCB. Send me a PM if you have one for sale.

Trond

After waffling around about which of the million different types of subwoofers to build, I finally decided to design one and actually build it!

The product manager side of me realized that I had some of the usual conflicting challenges as well as a juxtaposition of several different design goals. 🧐

The short (for me!) version:

Recently I was given for free a Sony RCD-W3 with the following symptoms, CD recorder drive reads CDs without any issues (haven't tested recording function yet because I don't intend to burn CDs on that machine) but the reader drive shows disc error after some seconds of it trying to read CD. Tried both CD-Rs and commercial audio CDs with same results.

First thing to do was to clean the lens but that didn't change anything. Googling the issue revealed that this is a common issue on several Sony CD recorder machines and the culprit is SMD electrolytic caps located on the PCB bellow the drives going bad.

I decided to check every single cap on that machine with my ESR/capacitance meter.

All the caps on the power supply board were found OK.

On the green PCB that hosts the back panel audio connectors all the caps were found OK except a visibly bulging Licon capacitor that is located next to the relay, so I replaced that cap.

Then, very carefully removed the 2 optical drives. You should try to remove the 2 CD drives and the PCB bellow them all together as 1 piece and not do as I did. There are flex cables bellow the optical drives that make it very difficult to work while the PCB and the drives are still inside the device.

Anyway, after carefully disconnecting the flex cables and removing the optical drives, I checked every SMD electrolytic capacitor with my ESR meter and found several of them to be bad, most of them totally open! I am really grateful that none of them leaked electrolyte on the PCB.

I decided to replace the caps with used capacitors I have pulled out of other machines, because the device is of no special value to me, economical or sentimental, so I didn't want to spend money on the repair. I also replaced only the caps that were found bad upon testing in circuit. There is a chance that there might be more bad caps there but due to being connected in parallel with other caps, the ESR meter was not able to detect it.

If your unit is important to you, it's better to try to replace all the capacitors on that board, using caps from known Japanese manufacturers rated for 105C, general purpose or entry level low ESR and definitely not ultra low ESR as that might detune the circuit. I used a mix of 85C and 105C capacitors that I first tested to make sure they didn't go bad in storage. Total number of caps replaced: 14
Number of caps left alone: 20

After the recap, reconnected everything paying attention not to damage the flex cables or break a connector.

Finally, I connected it to AC mains and made sure both drives now work without any issues!

The only issue that I found is that when I play extremely scratched CDs I get audible jitter, mainly on the repaired drive but also on the recorder drive on some occasions.

I attach some before and after pics of the repair for reference

Looking at the web page for LM4562 this morning I noticed that TI is marketing a device called OPA2891 as an alternative device.
OPA891 is a single, while 2891 is dual op-amp.
I have attached the datasheet, more info can be found here https://www.ti.com/product/OPA891

Looking at the datasheet is is dated November-23 and the devices seem to have similar "simplified schematic, noise and current spec compared to the AD797.
The single opa891 version is available for purchase at least from TI and Digikey.
Anyone tried this device or know where I could order a couple of the dual version. I'd love to try it in my upcoming Pearl-3 build

KPCU-1 0.22uF 600V: $50 for the pair
KPCU-2 0.47uF 600V: $90 for the pair

Prices include shipping to CONUS

I'm building the F5m amp and am starting to look at what speakers I should buy. I realize this is a huge rabbit hole but are there 'go to' speakers recommended for someone who is starting out with Class-A amp audio? I'm thinking a 'retail chain' pair of bi-amp Klipsh ( under $2000 a pair ) would be more than I will need but want to do a bit of shopping to see if there are others I should look at. I want some type of floor speaker ( not shelf ), and have looked at the MonkeyCoffin DIY build which I am considering as well.

I know for studio monitors, there are 'goto' suggestions like the yamahas or mackies and am wondering if there are similar safe-bet recommendations for speakers.

First PDF show the schematic diagram of power amp on page 2.
I note, usual topology for the output buffer (usual complementary discrete darlington power follower stage) is in use.
But the first stage of darlington use the same BjT types (Toshiba's 2SA1302/2SC3281) like the output stage (usual for first stage of such discrete darlingtons are e. g. Toshiba's 2SA968/2SC2238).
Is this a misprint or a special future from Classè Audio ?

If it is a special future, what advantage should be achieved (from my view the higher capacitive load represents a disadvantage for the previous cascode VAS) ?
Thank you for an advice.

images are here:
https://www.ukaudiomart.com/details...lasse-audio-seventy-amplifier/images/2959481/
https://www.audiosciencereview.com/...e-itch-again-looking-at-500-1k-dac-amps.6987/

P.S.: this thread don't provide the right information

I restored and recapped a SU-V7 and did all the adjustments except I can't get this one to work. Everything else works and sounds good. However, I can't get this one last adjustment to work. I think I am following it correctly.

I am using a 8 ohm load in parallel with a 33 ohm resistor (both 1%) so I get 6.44 ohms. I connect everything including the jumper and turn it on and I can get VR702 to adjust TP702 to -0.1 VDC but VR701 does nothing to TP701 which stays around 17+/-0.5 VDC no matter what position the pot is in (no change noted as I move the pot from CW to CCW. I tried replacing both pots with no effect. Also, I can verify that with 6.2 ohm load, it gets the correct supply voltage (~37V); with 8 ohms, I get the right voltage (~47V). With the jumper (TP703 to chassis) the unit doesn't come out of protection but once I remove it, the protection turns off.

Any suggestions? This seems to simple to get wrong and it is driving me crazy!!

Inside is a field coil made by Lowther UK

https://www.facebook.com/groups/lowthermodificationsupportgroup/permalink/1514513875767329/
https://www.facebook.com/groups/lowthermodificationsupportgroup/permalink/1514515712433812/

I am interested in measuring the vas of a speaker. I have looked at a few articles and they've said to build a box about the dimension of the. speaker as a cube. However, I feel that there is some incompleteness in the description of the process. I presume the speaker then gets screwed onto the box upside down. What doesn't seem to be explained is where exactly the measurement is made with the microphone. Maybe I'm missing something obvious. My apologies and thank you in advance for any help in this matter.

I have a USA-100 amplifier that has no audio output. I have rail voltage amp powers on and was wondering if anyone knows if the relay is for the audio phase?

I have a just bought a pair of Mission 782, which are decent Made in England 3 way speakers from the 90s, with a famous fatal flaw. The Audax made Keraform mid drivers all suffered corrosion on the coils from the glue they used reacting with the solder. It is terminal, and these ones are no exception with 2x dead mids.

I have ordered 2x Audax HM130Z12, which I have been advised are excellent replacements of much higher quality, although I am told they will require a bit of routing to make fit, which is no problem for me.

My question here is whether they genuinely are drop in replacements electrically, as the sensitivity seems to be lower than the earlier Audax HM130Z0 that Mission themselves used to replace the failing Keraforms.

The original (Mission branded) Audax Keraform 82-LF130/QS had a sensitivity I've yet to unearth. I can't find a datasheet online, and all surviving units seem to have failed due to coil corrosion.

The Audax Aerogel HM130Z0 that Mission used to replace these dead units has a sensitivity of 92dB

The Audax Aerogel HM130Z12 that I've ordered (as some say they are an improved version) has a sensitivity of 87.8dB

I'm guessing I may end up with a more laid back midrange than is optimal. Is that likely? Would I then need to attenuate the tweeter and bass drivers to flatten the response? What's the best way of assessing this?

Many thanks
Lucas

Im building the Elektor preamp with the canned MAT-02. So the layout on the board is for the TO-78.
The newer versions are in DIP format. does anyone know af an adapter to go from To-78 (on the PVB) to DIL 8 on the adapterboard.

Just done up today, one set of complete and tested Miro PCM63 DAC + JLSounds i2sOverUSB stack.
In my opinion, this is the most direct and best combo implementation of the Miro PCM63 DAC.
Sounds wonderful. It is a full, completed DAC, with a pair of AD797 op amp for the IV.
All resistors are smd, except the crucial IV resistors which are special high grade Vishay GSR.
https://www.vishay.com/docs/66004/gsr.pdf
Check their prices at Mouser by entering Vishay GSR. They cost $20+ a piece, with a MOQ of 25.

You need +5/-5V and +5/-5v directly to the DAC board. The JLSounds board's 'dirty side' is configured to be powered by the USB Bus ie. drawing +5V from your USB source. This can be changed to be powered from a PSU of your choice if you wish. Can be done very easily by cutting a pcb track under the JLSounds board as instructed by the user guide, and then soldering two wires from pads available on the DAC board out to the PSU. The XO and reclock circuit of the JLSounds is drawing +5V (digital supply) from the DAC board when you stacked and isolation from the USB 'dirty side' is achieved. Very neat and clean design, with full isolation achieved.

Case it up with transformers, PSU, connectors, a pair of op amps , connect it to a USB music source and you are ready to rock and roll.
All high quality parts are eg. Nichicon gold caps, Wima film caps etc etc... See the pics.
All parts are BRAND NEW including the PCM63P-K chips. They are installed for the completion and testing to commission the DAC.
Even the JLSounds board is delivered yesterday 1 November.

DAC Stack + shipping tracked & registered = USD 365
I am only ready to accept Paypal Family and Friends as payment.
As usual, I will also buy Miro some coffee as a token for his generous sharing.
I have shipped 58 packages to members here to US, UK , asia and Europe, not a single glitch so far.

More information of this DAC here :
https://electrodac.blogspot.com/p/dac-ad1862-almost-tht-i2s-input-nos-r.html
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-209#post-7049224

Information of the JLSounds i2soverUSB board. This is the USB interface that most members agree to be very good for the DAC.
http://jlsounds.com/i2soverusb.html

I built the Nelson Pass TL, with the Pioneer B20FU20-51FW following this plan: file:///home/martin/Downloads/Pass-BOFU-TL-map-300408.pdf

Great bass, I recently added some ESS AMT tweeters cut with a 2Mf capacitor. I will try to cut lower the ess around 2500-3500 hz, I appreciate your suggestions, thanks

I'm using them with Monarchy SM-70 amplifier.
an old thread about TL PASS

Hello folk,

I often usse trade offs for the casing of my electronics with wood knowing not being ideal (hlf sheildig effect of metal case).

So why casing became almost as much expensive than a finished low cost device with the electronic and the guaranty at the same price ?

Seems to me than transport increased fees is not the only culpritt ? VAT, well 20% averaage here in EC ? What else justification ?

So what else ? It is very no technology but is expensive (hifi 2000,, etc) !

For sale is 1 pcs of Fischer 56 200 SA black anodized heatsink.

Width: 300mm
Height: 40mm
Plate thickness: 10mm

Thermal resistance: 0.3K/W



Price is €80,00 with free shipping in Europe. Payment via Paypal.

I'm wondering if anyone might have Volumes 1 and 2 of the Audio League Report (1954) edited by Julian Hirsch which they might be willing to part with or have scanned?

All expenses met of course.

Hi guys

I am working on an Amp that went to another tech who did not complete the repairs. All the drive ICs have been removed. He did replace the power supply and output fets

Could someone please let me know what drive ICs to use here? Thanks Guys

Hi all

I've found this link: Audio Total Harmonic Distortion Analyzer for LTSPICE, making THD vs. Amplitude and Frequency sweeps in LTSPICE | Audio Perfection


I'm trying to understand how to use this script properly.
Can someone tell me how I can plot the THD vs freq graph?
After I've simulated the given example , I went to the error log (CTRL-L) and than I right clicked the log window.
THD vs output amplide graph appear after I select "plot selected meas data"
I have even changed the analyzer_controls.txt commenting the amplitude sweep and uncommenting the freq sweep but the result doesn't change: I cannot display the THD vs freq graph I'm looking for.
Cheers

Hi, not sure if anyone else here is interested in modding cheap DACs for optimal performance, that's my main hobby. Might participate further and build a nice NOS DAC though. Thanks!

I have built a couple if Bottlehead tube kits, and have a 300B project in the drawer in parts... Nowdays I mostly tweak my turntable and vinyl system. I like to do measurements in order to understand what is going on. I use a KT88triode coupled tube amp as headphone amp, using a APPJ adapter, I plan to optimize it with some mods.

Heya! I'm just some random person who decided that designing a microphone might be fun..? I've had basically no previous circuit designing experience or anything of the sort - it's interesting to say the least. Was hoping that someone could take a quick glance at the schematics maybe. It's been pretty fun!

Hi all,

Just join this forum.

My old Onkyo CD-Player, RC-625C, is not working recently. After placing CD on the tray and closing the tray, no indication showing on the LED display. After pressing the "start key" on the remote control a while, no CD Disc showing on LED display.

I have opened the CD-Player case and cleaned the LASER light with alcohol. Problem still remains. The LASER light holder can move on opening and closing the tray. But there is no light showing. Can I see the LASER light with eye?

Please help.

Thanks in advance.

Regards

I'm trying to fix my late 1980s B&O tape deck which was stored in my attic for over 20 years. I've replaced all the belts and the mechanical side works fine. But, there is no sound coming from the left channel. Initially I thought it might be a capacitor issue so I tested them all in circuit and found a couple of bad ones. I replaced them but still no joy.

I then checked the tape head. I connected a multimeter across each channel and found the right channel reading about 280 ohms but the left channel was open. For each channel I then connected the meter to an output and ground and played a tape. Both channels produced about the same millivolts, zero to about 5. I am now confused why there is an output from both channels.

Is the millivolt output a red herring and the true test is the resistance?

I've also swapped the channels over inside the tape deck and don't get any sound, left or right, which obviously indicates something else may be wrong with the left channel circuitry.

My thinking is to buy a replacement tape head from eBay and then start to troubleshoot the left channel with a head I know works. For all I know, just swapping the channels over may cause another problem which manifests itself as no sound. I can't think what, but as you've probably gathered, I'm fishing for answers to what should be a quite simple thing to fix.

Hi,

Can I have some opinions here please. I've seen a used pair of JBL k2S9800 speakers for sale for a similar price as what it would cost me to build Troels TL3. I've heard the JBL speaker at a hifi show a few years ago with Mcintosh electronics and it sounded fantastic, although there was ever so slight a bit of high end sharpness that I might find irritating long term.

I like TL3 for the speaker attenuation and the hypex amp, but how would they compare. Would TL3 be in the same league as the JBL?

I have this ubiquitous tiny DAC box. Just out of interest I would like to know what the DAC chip is. So I can look up specifications and such.

The large chip at the bottom side of the picture is a MS8416. This is the SP/DIF to serial audio decoder. The small chip at the upper half of the picture must be the DAC. The number 344C4042 does not hit anything.

General Transformer Sales Co. Ltd. now offer an international mail order service.
Payment by PayPal
Web site : gtrans.co.jp.
Their standard line is now discounted.
Finemet, Hashimoto and Iso transformers are made to order.
Use Google Chrome to translate from Japanese to English.
At the top right hand corner of the homepage click on contact.
A page will open and you can type in your request in English.
After that click to translate to Japanese, then click send in Japanese.
They will reply in Japanese and you need to translate to English to read.
Service is prompt.
They have a shop in Akihabara Tokyo.
It is run by old folks and is open only 3 afternoons a week.
If you are in Tokyo you can visit the shop, buy your transformers and save on shipping.
How ever they no longer stock Hashimoto and Iso transformers in the shop because of slow sales.
You need to preorder before hand.
I have visited their shop a few times and have recently purchased a pair of transformers by mail order.

SHAEK-BARE.PNG: I came across this "Shaek" clone of the Radio Shack
276-150 on Amazon when looking for something else. This YUNGUI item
was in Circuit-Breaker-Panels, not electronics. It is not very good
for soldering because the holes are too big for 1/4W resistors and
such. However, the layout is interesting because it has power rails
centered and there is room on each side of DIP sockets for related
resistors. This layout is logical and efficient. Such prototyping
boards are rarely seen now because they are mostly designed as
companions of plastic breadboards with 5-nothing-5 holes and power
strips on the sides.

SHAEK-ROUTED.png: Veroroute models vertical/horizontal stripboards but
does not have a model for hybrids. In fact, it can be used for any PCB
structure with standard spacing for holes and vias. A circuit can be
"painted" manually but I use the autorouter and add symbolic wires or
pads when auto does not go my way. I add a row of pads at the top to
mark how the strips are partitioned. Non-functional circle-X symbols
help to trace track alignment. See SB-ROUTED for more details.

SHAEK-TOP.png: I wired a small HeadAmp with two opamps plus linear
power supply(+/-12vdc) on the Shaek board. Everything fit when
planned using Veroroute. A headphone test revealed a rising high
frequency response probably from the unshielded external volume
control wires. A 100pf cap to ground pin 3 of the 4556 can produce
normal sound. The stripboard version has this fix. See SB-TOP.

SHAEK-WIRES: The holes are too big for the resistor pins. I had to
bend component pins to insure connection before soldering. There are no
interconnect wires on the copper side.

STRIP-LARGE.png: Stripboard or Veroboard has long, parallel strips of
copper which must be cut and/or bridged to create circuits for
electronic devices. This is easy for trivial circuits but becomes
difficult as complexity increases. Circuit tracks must be cut
(Carefully) with a 5/32 drill bit or sharp knife. It is easier, using
the Radio Shack pattern, to make vertical cuts (for partitions) across
all the tracks at once with a fresh hacksaw blade. See SB-WIRES and
SB-ROUTED.

SB_TOP.png: I was inspired by .Douglas.Self:Small Signal Audio Design'
chapter one which had a low impedance drive for tone control
circuits. It was not in the headphones chapter but it can drive them
with a suitable opamp such as 4556. Since the 4556 version merges gain
and buffer functions, there is no need for another opamp gain
stage. This is about using stripboard partitions, so a small but
usable circuit is satisfactory for demonstration.

SB_WIRES.png: First a 19-hole section was cut from a wide
stripboard. Then the copper was gently cut vertically with a fresh
blade to reveal two strips for the DIP sockets and separate strips for
the adjacent components. So there are four partitions. There are a few
spots where a copper cut is not desired and a jumper is installed to
"uncut" it. But this is less complicated than making random cuts on a
large stripboard. And stray capacitance should be reduced. There are
no wires on the copper side and the top wires are perpendicular to the
tracks for minimal coupling.

SB_ROUTED.png:

I add a row of pads at the top to mark how the strips are partitioned.
There are copper cuts at 4, 10, and 15. Non-functional circle-X
symbols help keep track of the vertical copper cuts.

HA-LITTLE.png: KiCad Schematic of "mother's little helper". There is a
schematic note "added C7,C8" to remedy spurious feedback or
instability from my crude setup wiring.

KI-PCB.png: Simple 2-layer layout of HA-LITTLE. There was a problem in
my routing attempt where I needed to use a via but could not get that
to work even after I watched a video where it was easy. So I redid the
routing to work with only two layers.
,,,

This is my first time trying to layout components onto an aluminum board, which I will CNC myself.

I'm interesting in what tips, rule of thumbs, etc, do others use when laying out components to be mounted to an aluminum plate.

In this particular case I'm laying out a modified version of Matt Renaud's Universal S4 pre-amp. I've added a DC regulator for the 12A*7 heaters and a cathode follower with a switch between it and gain. I now have more stuff than the original and need to modify the layout.

Thanks,

Hi everyone,

I have ZR360 on my bench as a learning exercise. I’ve found a couple of TIP transistors that are bad and a couple of sad transistors appear to be shorted. I’ve seen references in some posts here to notes on repairing these amps and potentially service manuals for some ZR amps. I’m hoping someone will be kind enough to share them with as I think they would help my learn process. Thanks.

G'day. I live in the Sydney area. I have an older Fender Rumble 30 bass amp that has stopped making sound; troubleshooting revealed the power transformer is dead. I have scoured the internet for a replacement part, to no avail. I am now looking for a suitable substitute transformer and thought the diyAudio community might be able to help.