I would like to know how to solder thru hole film&foil Capacitors

Hi !

I have an idea to replace cathode resistor and electrolytic capacitor with LED or SiC Shottkey diodes in amplifier with global feedback in PP amplifier. The only question remain how to re-connect global negative feedback resistor. One of the options is to connect it the grid of first input tube but it will yield high EMI noise pickup. So better to keep where it belongs to - in cathode circuit.
I attached 2 variants - which one is correct?
Thanks in advance.

I recently bought a pair of premade DIY pass labs Aleph 3 monoblocks.

When I turn one on, silence. But both, and whine develops.

The only thing that seems to stop it is if I touch the earth of one of the RCA inputs to the chassis of one of the blocks.

Any ideas on what could cause this? Or how it could be corrected? It's rather persistent.

The attached photo show a portion of schematic from a Philips CD60 vintage CD player (there is another thread with more about repairing this player after some damage).

Note 6502, the BC338 npn transistor powering the laser diode.

It's possible that the +10v rail this trans. is connected to experienced a power spike, as one of the fusible resistors was blown (see other thread) .

The laser power was waaaaaaaaaay off after the fusible resistor was replaced and Laser Output Adj (3520) was tweaked in order to get a CD to boot.

Some discs still don't track well (bouncy eye pattern), or produce mild audible distortion.

It's possible the BC338 was "affected", tho' it tests "okay" (its hFE is a bit on the high side).

Suggest an alternative (maybe even an improvement).
In my kit, I have Toshiba 2SC2240 and BC547.

If you think the original BC338 is okay, say so.

Thx

There are just a few videos in existence showing an individual assembling the particular elements within the envelope. We see people using very small spot-welders being used, fabricating tiny metal structures...nowhere do we see a so-called "exploded diagram"...are these tiny structures a true industry secret?
Let's see if we can find diagrams of these structures...& try to improve performances by analysis & optimization.


-------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...

I've been reading (searching the net) on the differences between the two:

1. It seems a bridge rectifier is more efficient in terms of the transformer construction.
2. The bridge rectifier has a bigger voltage drop because of the two diodes (maximum of .7 each)
3. Ripple is higher on a bridge rectifier

For an end user, I feel the transformer construction advantage might be not as useful.

In my case, I'm looking at two transformers which cost the same.

• 300VA 2 x 12VAC @ 12.5A (will be used in full-wave mode with ground center-tap. connecting the 2 secodaries in series to get 24VAC)
• 300VA 2 x 24VAC @ 6.25A (will be used in a bridge rectifier configuration)

Are there any other electrical advantages/disadvantages of one or the other? Is the current output the same/similar?

PS: I need +/- 30+ VDC after the rectifiers.

Thank you.

If any member has a CD3 power supply with transformer, I can make good use of it after mine has failed.

Not sure if this is a problem that others have had.

Regards all

Thanks

Well 🙂
Lets start with a picture.

Hi,
I am parting with a much loved pair of Curvy Changs that I built about 12 years ago they are fitted with FE206's (fitted with Decware type phase plugs) rather than 207's they have a shelving filter to compensate for the 206's rising response (at Scottmoose's suggestion) They are built from 24mm Birch ply and veneered in Zebrano and are very heavy. They have given me a lot of pleasure over the years and are in great condition, but its now time for a change of direction so they have to go, I'm open to any reasonable offers but they must be collected, we live in the Lincolnshire wolds in the uk, about 20 miles north of Boston.
Steve
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Top

Hello everyone! I've been in the need for a really good nearfield monitor speaker. I wanted it very compact and active. Also, it had to play at decent max SPL (around 90/93dB at 1 meter) in case I wanted it to fill my room. The FR had to be from 50 to 10000Hz (+-2dB) on axis.

For this reason my choice landed on the Dayton RS100-4 for its decent FR and good Xmax which is never enough for small drivers! The efficency is also decent with it being a 4ohm unit.

The FR doesn't quite meet the requirements but it seems like it can be EQd quite easily. I'll get a Sure JAB3-50 (it has a built in DSP) module to drive the speakers. Since I'm using DSP, I'll be making the speaker bass reflex because that way I can make an assisted alignment, also it's way more efficient than sealed.

3.6L net volume tuned to 55Hz with 2nd order HP filter (Fc=55Hz and Q=1,2) yelds to an almost perfect response. The SPL is also more than enough. This is the green graph.
But, in reality, tuning a small box so low is hardly feasible unless making a slotted port which comes with its own set of problems... mainly being much less efficient in terms of space and it also has higher losses thus lower efficency. If I use a round port I could make the box very tall and put the vent on the bottom, even if that wouldn't be very practical. Think about 11*14*25cm(3,85L). Even then I'd be limited to a 3,5cm port with a lenght of 24cm. This port has an airspeed of 31m/s (!!!) at 49Hz, with 30W input (not very realistic but I'd like to properly size the port), which is too high! I have to limit the power to 9W in order to stay at 17m/s.

So I started experimenting with passive radiators in WinISD, which also have their own sets of drawbacks, mainly the way lower efficency leading to a significantly lower max SPL (-2dB)!!! The two "best" radiators I could find for the price were the Dayton Audio ND140PR and the DSA135PR.

I put them in the same volume (3,6L) and tuned the enclosure to match the ported one (around 55Hz Fb).
The ND135PR required +18g (!) of added mass to tune at that frequency. I'm worried this might sag the suspension long-term. This is the blue graph.

The DSA135PR just +2g. With 30W input i'm VERY close to the 8mm Xmax for the DSA passive radiator but, between all the other problems, I could deal with this, if it wasn't for the massive loss in efficency. This is the red graph. I think this might be the best compromise, because even if I compare it with the ported version I'd be SPL limited way sooner because of that crazy high port velocity. Also I don't have to deal with chuffing.

The graphs do not include the filter.

How can I impove this design? Which one do you think is the best compromise? I would really like to keep the efficency of the ported enclosure without having to deal with the excessive port velocity. Do you think a slotted port would really help, even if it would make the box bigger? Thanks a lot!

I have an old (20+ years) set of these speakers that are starting to sound a bit "tired". Would it be worth replacing the crossover caps? The yellow caps inside say 4.7K 250. Is this the same as 4.7uF 250v? If worth replacing what caps would anyone recommend? Thanks

Alu Die Cast Cabinet: Monitor-Audio BM-100, Pioneer TS-X9 Bowers & Wilkins " ???"

I remember the good sonic quality of the speaker models mentioned here from early exhibitions and consumer shows.
I am looking to the B&W loudspeaker model, that is similar to the mentioned types especially to the outline of the "TSX9" from Pioneer. It was on the market between 1980 and 1990.
Who knows the model number?
And a second question: Where on the web is to find a test review and a frequency response of the BM100 from Monitor Audio.
Thank you very much. Here some images of the other above mentioned models.

Hi Guys
Been researching on parts to built my first horn speaker.
Due to my location, it would be ideal to use parts that I can purchase locally.
Looking into building a 2 way if possible with the above horns crossing over at 600-700hz. Size matters too as it’s for home use. Sensitivity of compression driver need not be high somewhere around 95-97 db or so would do.

Thanks in advance.

The history is short. I bought it for 15€. The device couldn't read any disc. I opened and the lens was not in the laser pickup. It's a typical fault in these series Pioneer laser pickups. I searched the lens but it was not inside the laser pickup. I thought to remove a lens from some Pioneer lasers I have, but these lasers pickups cost 100 or 200€ in the market. It don't worth. Then, I thought to use a lens from a chinese scrapped Sony KSS-240 or similar... I put the lens, it fitted perfectly, a drop of glue... and it works! It works perfectly. I adjusted a bit the "radial and tangential tilt adjustment", focus offset to O volts and perfect.

P.S: In the Pioneer PD-4700 service manual is where the grating adjustment is best descripted. If you want to know how to adjust the grating adjustment, there is the best description I ever found about it.

So, if you have a Pioneer laser pickup without lens because it had lost, get a chinese KSS and use its lens for to repair it.

I recently acquired a set of these boards and have read that there are issues with them. It relates to the bias and output transistors. I made the check of the bias as was mentioned in a previous forum and I get nowhere near the mv mentioned.
You are supposed to measure between the output with no input on and the middle leg of any output transistor, and you should get around 22 mv ideally. I am getting 1.4 mv. The DC offset is 10.4 mv and the ac ripple is near zero.

I ran the scope on the boards, and they do not put out the watts stated, only about 80 watts @ 8 ohms and just under 170 @ 4 ohms. The sine wave is clean with no ripples I can see, as I am worried about HF oscillations on this board.

Anyone has any thoughts on this, I was advised to change the 1k resistor to 910 ohms to have an ideal bias of around 22 mv.

Thanks Cheers Wayne

I asked a question here a long time ago regarding PCB for a Quad 405 clone. I built one and I like it very much, yes its an old design and there is a world of newer designs to utilise but each to their own.
I want to build another and gift the one I built to a friend, for the next one I would like to use 2x300VA toroid trafo and Elna 10,000uF caps that have been sitting on a shelf for a year. I have some extrusion as used in these cases Uniobox 2 - electronics enclosure kit - Lincoln Binns and want to build two mono units.
My questions are thus; where to find a good design for the two PSU required?
I would like to modify the amplifier circuit design to Snook or Net Audio, the boards in my amp are copies of the first Quad issue, the LJM clone. I see there is a copy of the 405-2 board available, which PCB is likely to need the least track cutting and component moves? On the 405-2 clone PCB I see that the input and output connections are spaced further than the first issues, design modification to avoid noise?

I read this thread from 2006 but nearly all of the links are broken; https://www.diyaudio.com/forums/solid-state/79508-quad-405-2-clone.html

I am looking for a saturable reactor for a General Electric e-126 colorama radio.

Hi, I again with my discussions.
I'm some time ago to update my old turntable, Aiwa AP2400, direct drive; 1982; with an Audio Techica AT 440 Mlb capsule.
For this reason I have read countless reviews and articles on current turntables.
I have focused on budget within which are Pro Ject Debut Carbon DC; Rega Planar 2; Pioneer PLX 1000
This last DD.
I read the argument of belt drive vs. direct drive, of which there is infinity on the internet.
The conclusion that arrives is that with audiophile purposes the belt drive turntables win and for DJ the direct drive wins.
The argument by majority is that the direct drives have greater motor noise when this is coupled to the plate, not so in the belt drive.
My dilemma is: I do not hear any Humm on my turntable, or on the speakers or placing a stethoscope on the arm bearing.
Also my reasoning is: how could there be Humm if the motor-plate turns at almost 2 RPM ?.
If I compare the specifications, the Humm of a direct turntable are superior to the specifications of a belt drive (Aiwa AP2400 has -70dB) (I clarify that the belt drive turntables in which the motor is outside the plinth do not enter into this discussion They are not in this budget)
And finally I saw a lot of post where there are complaints of Humm in Pro Ject and Rega, should do some DIY work to improve it.
That's why I'm in doubt about acquiring the Pioneer PLX 1000 or Pro Ject or Rega.
Greetings.

Regards,

Some "leftover" audio boards found. LM4780 stereo amp boards, assembled, tested, new and unused. Boards with power supply ( rectifier and 4x 4700uF on board..)..premium passive parts. Only needs transformer.

Three boards available, two are identical, one with different capacitors. Dimensions 145x65mm.

Price reduction: 30€ per board. Shipping ( registered with tracking..) 6€ for EU, 10€ other countries.

Regards, Davorin

Earlier today, I posted the following on Audiokarma. I think it should be on diyAudio too. Some of it I posted already in bits and pieces, but now it's more 'compressed', and under a better header:

For data on tubes, this is the site I go to:

https://frank.pocnet.net/

Note the "Much More" button in the upper right corner on that site. It leads to a wealth of tube manuals and other books on tube technology. The following link for instance leads to the sub-page with the Philips Series of Books on Electronic Tubes, to which I contributed a couple of books that I scanned myself (but not all are in English though):

https://frank.pocnet.net/other/Philips/SeriesOnElectronTubes.html

Scans of the "Philips Technical Review" and of some other series of research papers by Philips stood on a personal internetpage that was part of a larger Philips site, but some years ago they were all taken off-line. Luckely the scans of the "Philips Technical Review" series all found their way to the "World Radio History" site. But the other series of research papers did not. The same goes for the handy Excel indexes for all the series. But I downloaded all at the time and uploaded them to Google Drive. The links in the indexes themselves don't work anymore but they still are a handy tool for searching. Here are the relevant links:

https://worldradiohistory.com/Philips_Technical_Review.htm

https://docs.google.com/spreadsheets/d/15eXWd1afpPjQYcKAPBACx0oJB_qvy1za/edit#gid=248973280

https://drive.google.com/drive/folders/1m9aE3j9lX5IpH0vO0DTu1nhvkkQw9FMR

https://drive.google.com/drive/folders/1DFzUd18L5cMMKHzJrmWXwXwOhdtF_TZH

The following link leads to data/pictures/schematics/etc. I gathered through the years on the subject of tube testers. Almost all was found on the internet so don't expect completely new finds. But I think there's no other place on the internet at the moment where so much can be found at one place:

https://drive.google.com/drive/folders/1ep0Qgl2wqFCD2sZ4Q0Z3tFoaZxcrU7F2

A friend of mine will gift me a hand-built Hi-Fi without tubes, but I all of of them already. The schematic is in attachment, the only variation is that EL34s run with 43% UL taps instead of pure pentode (so of course the choke will work on the PI and driver only).

It is around 15 years old, and built based on this article, with some variations:
PP2010 - Hi-End Push Pull Amplifier

First of all I have one question: layout is same for both monoblocks (they are not mirrored), wiring is same, but whilst one is perfect, the other one needed a 50 kHz lowpass on the PI because of some autooscillations out of the audio band. Can it be due to some differences on the parameters of the output transformers?

Then I would like to ask you if you agree on some mod to be done this winter, after a long period listening to it as is:

The first one is to move the coupling caps before the 12AT7, to apply the bias to theirs grids and DC couple them to the EL34s and to be able to drive them into AB2 squeezing a bit more watts.
To do so I will rectify full bridge the 40-0-40V winding and the 12AT7 will be connected to that negative rail (around -112V) through the resistors (that could become a CCS indeed), while anode will be kept positive of course.

The other one is to apply shunt feedback to the EL34s, that in this case I would apply by connecting the plates of the EL34s and the 12AX7 with a resistor (I guess the value will be around 1 to 2.2 MOhm). Then I'll try it with and without GNFB.

If you see something better that can be done to it, I'll be pleased to try.

Thank you all in advance.

So I was thinking of getting an oscilloscope for the hobby (similar to the tektronic ones I used when I was studying computer electronics back in college) and came across the "new" generation of oscilloscopes.

feedback on these?

Thanks

EDIT:

• I am looking at the $200-$300 USD range.
• not sure what is digital audio (the frequency range) but will be use to "debug" the various DIY projects (2 channel ones). I don't think I'll be building a DAC.

I've got a simple question for those who claim that they can hear absolute phase. Which one is it?

It's pretty arbitrary to post my question here. I do it because I am especially interested in hearing an answer from Nelson Pass.

I am a sound engineer, and I don't hear absolute phase. I hear phase anomalities, and I hear the moment when you change polarity ("flip the phase" - phase is actually a term for a time domain phenomena, while polarity is the correct term for what we're talking about). But I don't get the talk about "absolute phase" (intellectually I do, of course, but physically and physiologically I have doubts).

Consider a kick drum. When the drummer kicks the kick drum, the skin moves forward first. Now consider the microphone in front of the drum. What happens to its diaphragm at that moment? It moves backwards. So the polarity of the wave has been reversed. This wave with its polarity is what is actually recorded. NOT the polarity of the wave that emanated from the kick drum, but a polarity reversed copy of it.

If we take for granted that the mixing engineer and the mastering engineer don't alter anything in the phase or polarity of the signal (which is far from being a given - very common alterations vary from none to polarity reversal to frequency-specific phase rotation), the loudspeaker will reproduce what the microphone has recorded. This has a reversed polarity in relation to the wave that originally emanated from the drum.

So which is the "correct absolute phase"?
Do you reverse the phase of everything you're listening to, because then it represents the polarity of the original? Which one is the "right" "absolute" phase?

And do I understand it correctly that this whole discussion about absolute phase is strictly about the onset of a wave, and non-periodical signals like short transients? Because once the wave has started, it's a wave, a continuum. I must admit that I don't get the whole concept, but that's yet another topic.

EDIT: The simple solution that polarity is reversed in the microphone' setup (coil and magnet orientation in a dynamic microphone, for example) or in the wiring in order to represent the polarity of the signal recorded didn't occur to me. Thanks to all who pointed that out!
Some other aspects of my wondering still remain open, though.

hello Chaps
can someone please confirm crossover values of the speakers above, is there a specific mod or a general consensus about a great component replacement
regards
Andre

I bought a Consonance M100D amplifier a few years ago. currently one of the output transformers is burned. I've contacted customer service by email, but no response. what should i do . Is it safe to replace the output transformer with another brand transformer? .

regards;
Hastomo .

I used to diy speakers many years ago, but I'm getting back into it for a one-off project - pair of two way TL speakers.
I'm not very switched on with current crossover software.
I've been practising with Xsim and VCAD.
I like the power of VCAD, but I'm a bit worried that I might end up with a bad design if I inadvertently apply the wrong settings in say Preference Ratings.

I will be doing a range of horizontal measurements (for my FRDs) in an elevated outdoor area which should have no early reflections.

I've put a lot of work into the enclosure design (Hornresp), and a lot of work into the construction (I'm not a cabinetmaker's a***hole).
So I want the crossover to get the best out of my speakers.
Should I continue trying to learn VCAD, or just stick with Xsim?
BTW, I'm not an audiophile, and the speakers are only for casual listening in our untreated living room (maybe that answers my question. 🤔).

I've got a Onkyo BD player with drawer issues where it pops out about 10mm and then closes. I've changed the drive belt as well as cleaned and lubricated and works fine until the next time it's used about a week later. I grab the drawer as it starts and pull it out and then close. Works fine for the full session after that but not the next time. The distance it comes out seems to line up with the change in direction in the track for the raising mechanism (see pic yellow arrow).

As I only use it once a week I have no problem with it operating this way and additional repairs are beyond me these days. The question I have, does the drive motor for the drawer lose strength over the years?

As far as I know, the possibility for a thread starter to edit his/her first post indefinitely was made possible to make searching on this forum easier, so more effective. A threadstarter could for instance add (a link to) the solution to his/her original problem, or rewrite the original problem, so as to make it more clear for someone that starts reading the thread.

But this possibility to edit the first post indefinitely has a serious drawback, at least in my opinion. I stumbled on a forum member who, after he/she got his/her solutions to his/her original questions, edited many of his/her first posts in such a way that the original questions were no longer in the first posts. After the edits, only something like: "Thank your all, the problem has been solved" was all that was left.

When I did some searching on the internet, it became clear to me, what the reason for this behaviour is. The person get's his/her answers here on diyAudio just to impress others on some other forum, of course without mentioning that the answers came from members of diyAudio. I'm pretty sure that this person wants to cover his/her tracks as soon as he/she got what was wanted, just to minimize the chance of getting unmasked by members of that other forum.

So a very good intention by the people who make diyAudio possible is being misused in a way that is completely against the spirit of the intention...

I'm sure that a vast majority of the diyAudio members will never act in such a way. Because of that I think that the possibility to edit the first post indefinitely still has more advantages than disadvantages. But I did find it important to warn others that this kind of flagrant abuse does happen on diyAudio.

How can you bridge this BT 2x100w TPA3116D2 amplifier to 200w mono ? Can you simply connect speaker to R+ and L- ? I know nothing about feedback loops.

https://m.aliexpress.com/item/4000312573172.html

Hello all
I am looking for recommendations on a small power class D that can be reasonably easily soldered with discrete through components other than the chip, and hopefully there is a chip that isn't too difficult to solder. There are plenty of prebuilt boards with various chips out there, but I want to try my hand at incorporating a power supply on the same PCB and make it easily conform to a stereo or bridged mono depending on use at hand

For me, it would be nice to have some sort of switching power supply all on one board

Around 50wrms into 4R x 2 channels is plenty for what I would do with this. If anyone takes an interest in a project like this, then I also welcome any type of group effort on the PCB and parts. I am also happy to have a small batch of PCBs made and send to contributors for cost plus postage

My reason for wanting such a unit is to use it in a bass amp that I am building for sale. It contains two biamped drivers, and one is a high-passed full range that needs this smaller amplifier. For the bass driver, I am sourcing the amplifier board from a forum member, Eric. This board has a built-in PSU. This is a small amp using 6.5" drivers and my jfet pre sections

Thanks and regards
Randy

I didn't know where to post this, whether here under this thread or the tube/amps threads? As it applies to vintage electronic equipment.

I just wanted to share some pretty decent results in obtaining the vintage wrinkle paint look/finish we see on old electronic equipment, The brand paint I used is
called 'Dupli-Colour wrinkle finish' black.

The instructions on the spray can indicate, apart from the usual making sure the pieces are oil, dust and wax free. To spray one thick coat in a horizontal fashion then leave it for 5 minutes, Then spray the second thick coat in a vertical fashion, Another leave it for another 5 minutes, Then spray the third thick coat diagonally.

The instructions also indicate that if the paint doesn't start to wrinkle to give the piece a fourth coat, However, I then placed the two pieces under a 500watt indoor work light for approximately 30 minutes, The results look pretty spectacular.

The work light I used is the type painters and decorators use indoors they do produce a lot of light and heat, I don't know whether the heat from the work light helped with the wrinkle process of the paint but I was blown away withe the results.

The instructions on the spray state the normal drying and hardening process takes two days. The test pieces I used are the covers of a filter choke. I hope this can help others out.

cheers Ron

PS Mods: if this needs to be moved to a different section please do so.

Hi
I am trying to fix this amp which uses a class D power IC (TDA8954TH) . The amp went dead and upon checking, I realised that the bridge rectifier and transistor Q7 (TIP102) has shorted. I replaced them and upon powering up the transistor blew again. This time I realised that resistor R53 (10 ohms) has also blown. I remove the TDA8954 and upon checking, I realised that there is continuity between pin 24 of the IC and the metal tab of the IC. It shows 0 ohms. Also there was no Mica insulator between the IC metal tab the metal chasis. Does this indicate that the IC has shorted. I have a TDA8950th at hand. Can this IC be used as a replacement. Please assist. Refer to attachment.
Thanks
Carlos

Does anyone have an valid physical explanation of why speaker and interconnect cables need running in. Also told recently that amp needed running in due to capacitors, always been my understanding that caps charge up quickly, and get worse with age. ???
Mike 😕

Hi All,

In Class AB amplifiers with mosfet outputs, it is common to see zener diodes from the gate to source to provide current limiting and protect the gates from overvoltage. However, the zener is often shown in series with a normal diode. For example: Rod Elliot P101 Mosfet Amplifer Schematic

What is the purpose of this diode and does it need to be anything special or is a normal signal diode ok?

Many thanks,

Greg

I do not know if this has been covered in a thread before, but...

In comparison to Tamura , Tango used a lot of "unclear" info and different abbreviations for their (output)transformers
X
XE
FC
FE
FW
FX
CDR
U ...

-does this have anything to do with the material/core/construction/quality ? Info (also on the net) is quite vague...
-which came first : Iso tango, tango,etc.. and what is up with the "new" production of Tango? This is not produced anymore in Japan? What is the quality of the "new" production ?

Any reliable info would be appreciated, cheers all!

PCB + Parts kit for the Mezmerize B1 Buffer, including Toshiba JFET's (4 matched and 6 unmatched).

Asking $120 shipped in the US

When doing sound for a festival, the event is usually outside and often powered from generators.

As virtually all pro sound equipment is solid state are there any products that have special issues from the generally lower quality of the AC power.

For example Hammond organs tone generator is tied to the frequency of the AC line. So special modifications are required to insert a stable frequency standard.

Some folks swear the guitar amplifiers must be tube designs for best results, other folks insist on solid state units.

Anyone have actual experience with these issues?

The Revox B77 control unit can use the SC10429 chip with a substitution logic PCB, or a newer version using a ROM chip. As a ROM, a chip of the N82S123N type with a capacity of 32x8 bits is used. If this chip fails, there is a problem of finding a clean chip (or replacement, for example, IM5610CPE), as well as a programmer for it. The contents of this chip were found on the revoxforum.ch forum:

2D 2D 8C 0D 3D 3D 9C 1D 89 0D E7 6D 99 1D F7 7D
2D 2D 8C 0D 2D 2D 9C 1D 89 0D 6D 6D 99 1D 6D 6D

But such ROM chips have not been used for a long time, so it is very difficult to find them, as well as a suitable programmer. Therefore, I decided to go the other way - I made a ROM emulator on a microcontroller. When the state of the input pins changes, an interrupt occurs, and the necessary output pins levels are set in the handler. After that, the microcontroller goes into sleep mode (Power Down), when the clock generator stops. This eliminates interference on the analog path of the tape recorder. To make it look nice, I took a microcontroller in a very small package - ATtiny2313-20MU (QFN package). As a result, the dimensions of the board turned out to be the same as those of the DIP-16 chip. The layout of the board is made one-sided for its manufacture by hand. By upgrading the firmware of the microcontroller, you can get additional functions of the control unit. For example, a version with "Pause" mode latching has been implemented (file B77_rom_pause_lock.hex). The board is very small, so there was not enough space for a programming connector. Instead, there are special points on the board where you can solder the programming connector with wires and then remove it.

Hello,
for sale:
- phono Salas Folded Simplicistic pcbs complete set, with a pair of 2SK369 ( MM version) and some resistors as you can see in the picture for 45eur+ shipping and Paypal Fees.
More info:
https://www.diyaudio.com/community/threads/gb-for-salas-folded-simplistic-phono-pcb.241736/

- phono Actidamp MK3 V2 MM preamp with some the passive components and the RIAA caps, all from Mouser, no caps on the segnal path, very hard to find , comes with the manual, as in the picture for 45 euro+Paypal fees and shipping

If needed I can supply for this boards matched piars of 2sk17bl at 6euro per pair. The 2sk170bl are from Spencer.
Best regards
Guglielmo
Italy

I'm looking for next suggestions on my audio journey so I thought I'd pick some experienced and brilliant minds (is that enough sucking up? 😀). I'm trying to decide which would be more useful and what options I have in those fields.

For an ARB I want to use it for audio (including measuring noise/THD), RF (AM/FM) tuning, and also DSD (preferably up to 512, ie 24MHz). Budget ~£300-400. Bonus for USB/LAN connection. The natural selection would be the Silent SDG1000X which would work with the SDS1104-E for bode plots where currently I have a python program allowing me to use the Mac mini as a bode plot sine generator between ~4-20KHz using the headphone output.

For a sound sampling input device it would need to work with a Mac mini (USB/ethernet/thunderwhatsitsface) or in a Linux VM with a preference for open source for working in VMs and to counter the Apple 3 generation support. I used to have an Audiophile firewire but that's dead as a doornail.
There's not really a large range of USB sampling devices for the Mac and what there is tends to be overpriced for what they are.

I picked up a Pioneer PL-41 last year and while I love the table the arm left a lot to be desired. So I gathered up the numbers for the stock arm and found a perfect drop in replacement. The Grace G-545F.. Spindle distance is exactly the same. What was really amazing was how much it improved the sound of my TT. I am running a Denon DL-110 High Output MC at 2 grams tracking force. Loads of well defined detail but very smooth without sounding rolled off. Transients are fast and have the right amount of attack and decay without having to fuss with with anything. I am making a custom Plinth for it next. I paid $200 for the arm in near mint condition on Ebay and picked up the deck local for $250. I think once the plinth is done I will a mighty fine looking and performing TT for not much money. Including cable I will have about $1k total (with cartridge).
Highly recommend this arm as a drop in replacement.

Jeff

I've got this 100W Peavey combo which I like to run from mains through 60W Light bulb. With the lower voltage it also has a sag and sounds great for recording. I tried Variac which lowers the voltage but that can't provide the sag. Is there something I could build in to the amp besides stuffig the light bulb inside?
I thought about resistor with heat sink which should act the same as the a light bulb, but my calculations come to 0.4A resistor which seems a bit small to me. Perhaps there are better options?

as above.

I've used it in the past to connect PCBs or connect transformer primaries to IEC connectors without having to solder the wires.

Thank you.

Hi folks,

I have a few 6AS7G tubes at my disposal.
I'm actually using them as output tubes, in cathode-follower arrangement.
They eat up a lot of heater current but look good..

Anyway, now I want to try them in a classic grounded-cathode topology.

So, what do you guys think of these values?
(forgot to add an 1k grid stopper)




Will feed a following tube stage.

I would appreciate your help, since I am not very confident I got this right.
Thanks!

ALL SOLD

Let me know which line items you are interested in and I can get a shipping quote for you. More complete testing data on most tubes is on a sticker on the tube box. These tubes come in generic white boxes with the testing data on the box. Please try to include the tube numbers in the line item when emailing me.
These are all nice basic tubes, sounded good in PP amp front ends or preamplifier applications. None are very microphonic.

I can get you more complete data or pictures if you need it.

I will remove tubes from the list once sold.

6SN7 VARIANTS

Tested on:

eTracer new gm is 2600, 80% is 2080, 70% is 1820

TV2-C/U minimum is 59

results are for triode 1 / triode 2

6SN7 GTA PAIRS $25/pair $15/pair

1) SOLD

2) GE Side Getter Short bottle #1104,1101 2504/2392 2488/2651 88-90/59 96-92/59

3) SOLD

4) SOLD

6SN7 GTB PAIRS $25/pair $15/pair

1) SOLD

2) SOLD

3) SOLD

4) RCA Bottom D Getter #1079,1021 2572/2584 2622/2671

5) SOLD

6) SOLD

7) RCA Bottom Getter #1023,1022 2935/2274 2256/2289 86-109/59 82-83/59

8) SOLD

9) RCA Side Getter #1078,1077 2132/2051 2417/2420

10) SOLD

SINGLE TUBES $5/EACH

1) SOLD

2) SOLD

3) SOLD

4) SOLD

5) Mech #1080 Bottom D getter 85-85/59

I acquired 4 of these drivers a few years ago. I am planning to build 1 subwoofer for 2 channel fed by a commercial amp. Later down the road I plan on building a second and incorporate it into a 2 channel/ HT setup. Since I already have 4 drivers, I was thinking of 2 drivers in an isobaric set up in a sealed box to reduce the size of the enclosure. The only negatives I can think of are cost and a more complex build. I bought the drivers years ago (used) so cost is not a consideration and my woodworking skills are good enough that the box construction would not be difficult.

Can anybody think of other reasons Isobaric is not a good choice and which Isobaric configuration is favored?

Thanks

Clarke

I have a Pioneer SPEC 2 amplifier on the bench with a capacitor and transistor on the modules thats not been documented in the service manual. Anyone aware of this?

I have to map it out but I am curious if anyone else has encountered this.

I could not find a similar topic or discussion. This is not an issue / bug.

Is there simple way to choose a sub-forum, Tubes/Valves as an example, and display only the unread threads and/or sort by read/unread? I'd like to do this without watching every thread within the sub-forum, but that is a solution.

Hi, I just purchased B&W Matrix 804 on eBay,, Despite almost 30 years old vintage speaker, it is still in good shape but want to replace the crossover if possible just the capacitor,, There are 2 crossover boards one for lower frequency and the one for higher frequency. The capacitor for lower frequency is Bennic bipola 7mfd at 70 watts,,, Only thing I can find on the web is 6.8 mfd at 100 watts,,,from Bennic. Is there any better alternative? For the high frequency board there are 2 caps from Bennic but they are seems like poly film caps. My understanding is that poly caps usually do not go bad unless it has been abused or do I also need to replace 2 poly caps as well? New to the hifi world and really need your opinion on the subject. Thanks

Hi all, i have an OEM 15" driver.....so no T/S parameters.....and am in the process of learning how to measure T/S.
I want to try the driver in sealed and ported boxes....for sub duty up to say no higher than 120-150Hz...and of course as low in freq as possible.
Once i measure T/S, I'll take it to Hornresp....

In the meantime, i've done an impedance sweep...free air, pointing up, sitting on the floor.
I've never seen such flattish impedance curve on a low end driver; have always seen a much sharper peak at fs.

Can someone tell me just from impedance, what to expect from this driver? How probably to best use it?
thx Mark

<all gone as of Jan 2024, thank you.>

As part of my miro DAC experiments I bought the last Burr-Brown marked PCM56P-J from Rochester and had a few boards made. They sound very nice indeed, but I have too many.

• Complete and tested DAC board: all new parts including PCM56P-J, Wima and Elna Silmic caps, Vishay resistors. No op amps supplied, choose your own adventure. $100 + $10 postage in the US, $20 rest of world
• 3 pairs of PCM56P-J chips available
  • 2 chips + board $35 (one set left) (have 2 sets)
  • 2 chips alone $30
  • Same postage as above, they're too thick to go as an envelope. Buy as much as you want for one shipping charge.

When a tweeter is described as "vented", can we presume that it does not use ferrofluid?

Specifically, I am referring to KEF's Uni-Q drivers used on LS50 meta.

SOLD -- SOLD -- SOLD -- SOLD
Still digging stuff out of storage This ferrofluid is left over from a patent I was working on quite some time ago. I had two of these, but haven't come across the opened one yet. I recall it being well over $1000 for both bottles direct from Ferrotec. Will sell this unopened one for $99 plus actual shipping from Carlsbad, CA 92010.



Cheers, -Casey

Hi

I have these 2 tqwp cabinets to give away (there is only one on the pics to give you an idea)
I believe they are 22x35x120cm and I think I followed DHTRob plans:
DHTRob - Tapered Quarter Wave Tube (TQWT) loudspeakers
I used 18mm MDF.
One speaker has some water damage on top (see pics, soap bubble gun...). Nothing that cannot be sanded and repainted.

They were meant for Philips ad9710 full rangers (9.5'') Unfortunately one of the drivers I bought was defective and finally the project has been forgotten.

I have been playing with the idea of experimenting with them but I am too busy for that.
Also my Troels Gravesens's Vifa C17 d'appo is doing great and are not too shabby in the efficiency department.

The cabinets are for collection only.
I am in London (1-2mins from a major highway so easy to get to).
If you can bring some other diy stuff to swap that would be nice, but if you don't you can have them anyway. But please make sure you will use them!


I can add one ad9710 - not alnico (and what is left of the other one) for a small fee.
If you feel like like just experimenting with full rangers in a tqwp I have some other vintage 8'' philips drivers for a small fee or to swap. 8'' drivers will need an extra baffle with the correct size opening for the driver.

Hi
Even though I've designed and built many speakers over the years (several 2 way sets; HT systems; Infinite baffle subs; folded horn bins), I haven't really done anything in 20 years, so I want to take the easy way out, and buy a pair of DIY Proven Design speaker kits - ideally with flat-pack cabinets..
I've sold off most of my previous designs, so all I'm after now is a stereo set of speakers for our living room casual istening (RnB, Blues, Rock, Clasical).
Budget is $300-800 US.

I've been trying to buy a set of Swan 3.1A DIY kits, but after trying all the various available emails, etc. I've so far had no luck.
So I'm now thinking of a pair of Paul Carmody's Overnight sensations.

But I'm throwing this into the forum to see if there is something else out there I should be looking at?
The two things I would prefer included in the kit would be flat-pack cabinets and circuit boards for the Xovers (if the crossovers are fairly complex).
Also a great sound stage would be high on the list.

Any ideas?🙄

Some "leftover" audio boards found. Single ended to balanced boards with BurrBrown DRV134. Also great for bridging amplifiers. Assembled, tested, new and unused. Three boards available. Price 10€ per board, shipping ( registered with tracking..) 5€ for EU, 10€ other countries.

Regards, Davorin

So, a friend told me today of his weekend experience. Apparently the renters in the bottom part of the house blew the dryer breaker. When the landlord came over to check, he noticed there were more breakers that had popped. So he reset them all, and again when the dryer started, not long after, its breaker popped again. Shortly after this, as I understand, my friend noticed a burning smell in his part of the house, upstairs, and soon discovered that the power bar where he had his smart TV hooked up to burned! I saw the picture, there was a black streak on the wall where it's mounted (the power bar) and a big, 1 inch hole in the back of it. His guess was that the MOV or whatever protection device did its job, but seriously, the thing could have practically caught on fire...

Does anyone have an idea if this is a surge of some kind? There was no lightning or bad weather when this happened...

Wow have the prices of everything at Partsconnexion gone way way up! Mills resistors have over doubled in price since last week. Alps pots have gone up by a third. That is a crazy amount of increase. Anyone else found their parts are going through the roof?

(2) Peerless Exclusive 8" 830884. New in the box. $120 SOLD

(2) (4) Dayton ES180TiA. New in the box, one was removed for measurements in a project that did not move forward. Awesome motor and low distortion. $350 $200

(2) Peerless Nomex 5.5" 832873. Lightly used. $100

(2) Dayton AMT2-4. New in the box. $110

(2) B&C 8NDL51-8. Used for measurements but never used in a speaker. $200 SOLD

(1) Scanspeak 2104/7120 3/4" Revelator tweeter. New, only used for measurements. $125

All prices include shipping. Paypal only. CONUS only.

Good Evening Everyone. Am looking for a nice used pair of the Visaton B200 speakers. Looking for a project for a friend of mine. Thanks Jeff

https://www.popsci.com/technology/carburetor-repair-rileys-rebuilds/

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Hi all
Can anybody share me the value of resistor R596 please. Thank you.

Edit: Disregard this post, I'm going to hold on to these SITs a little while longer -- in case that build-bug bites again. 😅

Sorry about that.

Might anyone be interested in a pair of either 2SK180 or pair of 2SK182ES?

I've recently acquired THF-51S for my next amp build and so I don't think I'll likely end up getting around to using these.

Both were acquired from Mr..Tomo Watanabe, and both are a matched pair. Unused, NOS.

Would be willing to discount when purchasing both pairs together.

Shoot me a DM if interested.

I had the idea to make a "tube DAC", simply as an exercise to see if it could be done. I've seen a few designs that seem to achieve this. I also saw somewhere that R2R DACs can be implemented entirely with resistors, not requiring any active components? I'm making this thread to clarify my assumptions and what possibilities there actually are. Practicality and distortion are not specifically priorities here; while I may not proceed to build an impractical, high-distortion design, I am interested in knowing it exists.

Hi all,

Recently bought a used Chorus LCR700 (built in 2001, I believe). The low frequencies are muddy and lack dynamics, mids sound shouty and nasally, and the highs are smeared and lacking detail. Please provide specific component replacement recommendations for the crossover. I aim to keep to this project under $100. Thanks!

Here's the method I use for running my DATSv3 natively on my Mac using REW.

SOLD

I've cleaning up my shop and getting rid of some redundant equipment, so this very nice scope is moving on.

Tektronix 2225 50 Mhz Oscilloscope and P6103 50Mhz 10x probes

Classic analog oscilloscope in excellent physical condition and good electrical operating condition. They don't make them like this anymore. Both channels work as do both probes.

For now, I'm limiting this to the SF Bay area since I don't want to deal with shipping something of this size. I will be attending Burning Amp in SF the weekend of October 15/16 and could bring it there. I'm located ~40 minutes south of SF on the peninsula. I'm looking for $175 but open to reasonable offers. I'd like to see this go to a good home.

https://download.tek.com/manual/tek_2225_op_and_opt.pdf
https://download.tek.com/manual/071615600web.pdf

ID this mid horn (Community VB790?)

Anyone recognize these? Friend is selling and might be able to pickup cheap. Any other thoughts welcome. Sarcasm encouraged...

as above.

browsing mouser's catalog, I've seen the usual suspects like wirewounds but also come across "current sensing" resistors (link) which is non-inductive at values below 0.25ohms.

can these be used?

Thanks

I think my tweeter voice coil was cut, so I am trying to replace the coil. However, magnet glued to the face plate. Any idea to replace the voice coil??
Please advise.

Many turntables are equipped with a strobe light. The platter has marks that are illuminated by a pulsed light source. If the rotation speed is exactly such that the marks move exactly their step size in a time equal to the flash period, then the marks will appear to be stationary. This property is used to check disk rotation speed. Often the strobe lamp is powered by mains voltage, so mains frequency error will result in speed error. It is desirable to stabilize the frequency of the stroboscope with quartz.

When powered from the mains, the strobe lamp flashes 100 (50 Hz region) or 120 (60 Hz region) flashes per second. To obtain an accurate speed of 45 RPM or 78 RPM, it is impossible to find an acceptable integer number of marks. Therefore, these speeds are set approximately.

For the 50 Hz region:
Nominal speed: 33 1/3 RPM, real speed: 33 1/3 RPM, number of marks: 180
Nominal speed: 45 RPM, real speed: 45.113 RPM, number of marks: 133
Nominal speed: 78 RPM, real speed: 77.922 RPM, number of marks: 77

For the 60 Hz region:
Nominal speed: 33 1/3 RPM, real Speed: 33 1/3 RPM, number of marks: 216
Nominal speed: 45 RPM, real speed: 45.000 RPM, number of marks: 160
Nominal speed: 78 RPM, real speed: 78.261 RPM, number of marks: 92

To get an accurate value for any speed, it must be possible to fine-tune the flash rate of the strobe in small steps. All 3 sets of marks are not always applied to the platter. Sometimes there is only one set, then to check different speeds, you need to change the strobe frequency. All this requires some flexibility from the stroboscope.

The stroboscope is based on one of the smallest microcontrollers ATtiny12L. To generate the flash frequency of the LEDs, a software-implemented NCO (Numeric Controlled Oscillator) is used, which is usually one of the components of a direct digital synthesizer (DDS). This provides a frequency step of about 0.001 Hz, which allows any quartz to obtain any output frequency within this accuracy. This is an advantage of NCO over a simple divisor.

The stroboscope has the ability to generate 4 different frequencies, which are selected using the SEL0 and SEL1 inputs. Each of these frequencies is specified in the source text as a constant and can be any. The constants for the frequency code are calculated automatically. As the initial data, you must enter the desired speed with an accuracy of 0.001 rpm and the number of platter marks. For example, 50 Hz turntables typically have 180 marks for 33 1/3 RPM and 133 marks for 45 RPM. Based on this data, frequency codes are calculated at the compilation stage. For a speed of 33 1/3 RPM and a number of marks of 180, the LED frequency will be set to 100 Hz. And for a speed of 45 RPM and a number of marks of 133, the frequency will be set to 99.750 Hz, which will give a speed of exactly 45.000 RPM. The speed of 78 RPM can be checked on any set of marks, 180 will be set to 234 Hz, and 133 marks to 172.9 Hz.

#define FREQ_1 FREQ(33333, 180) ;preset 1
#define FREQ_2 FREQ(45000, 133) ;preset 2
#define FREQ_3 FREQ(78000, 180) ;preset 3
#define FREQ_4 FREQ(78000, 133) ;preset 4

In order for the marks to be sharp, the duration of the flashes must be short. The duty cycle of the LED flashes should be 4 ... 16, shorter flashes give a clearer picture of the stroboscopic marks. In the final version of the firmware, the duty cycle is set to 16.

There is another problem - the stroboscope can become a source of interference. A pulsed current flows through the stroboscope LEDs, and if the stroboscope power wires are long and close to the signal wires, interference may occur. Another possible cause of noise is that the LED supply current can create a pulsed voltage drop on the ground wire. For this reason, some turntables have the ability to turn off the strobe. To eliminate the problem of interference, it is desirable to localize the pulsed currents within the stroboscope board, and make the current consumption of the board as a whole constant. To obtain a constant current consumption, a current source is used, implemented on transistors VT1 and VT2. This current source charges the capacitors C6, C7, C8, from which the LEDs VD1 ... VD3 are powered. If the voltage on the capacitors exceeds a certain threshold (about 4 V), the parallel regulator U3 (TL431) turns on, ensuring a constant consumption even without working LEDs. The simulation graph shows that with a total LED pulse current of about 60 mA, the total consumption is about 16 mA, and it is constant.

The stroboscope board can be powered by an external voltage of 5 V. For versatility, a U1 stabilizer is installed on the board. As a result, any voltage within the range of 7 ... 20 V can be used for power supply. If there is a voltage of 5 V, the U1 stabilizer can be excluded.

The stroboscope printed circuit board is single-sided, 30 mm x 40 mm in size. In order not to drill any holes at all, all parts are soldered in the manner of SMD. Electrolytic capacitors are soldered with shortened and slightly bent leads to the pads. The programming pins are soldered as follows: first, the plastic moves up, the pins are soldered to the pads, then the plastic moves down again.

The convenience of this stroboscope design was confirmed during the repair of the Bang & Olufsen Beogram 2000 turntable. He has only one strobe scale, which contains 180 marks. There is no built-in strobe light. For a speed of 33 1/3 RPM, you can use, for example, a neon lamp powered by a mains frequency of 50 Hz. But how to check the speed of 45 RPM? With this strobe, it's simple - you can add the output frequency FREQ (45000, 180), which will give 135 Hz. The marks on the Beogram platter are very high quality, so it was possible to check how the duty cycle of the LED pulses affects the sharpness of the edges of the mark image. With a duty cycle of 4, the marks are quite blurry. With a duty cycle of 8, it gets better, with a duty cycle of 16, the image is close to ideal, a further increase in the duty cycle is not required. This duty cycle is set in the final version of the stroboscope firmware.

The stroboscope can be built into the turntable or made as an external device. In the second case, you can use, for example, a phone charger as a power source.

So, I had a previous thread here wherein I used an instrumentation amplifier with mixed results, to act as a preamp for a balanced piezo pickup. It was determined that I had unnecessarily used low-value caps in a HPF on the input, and also I was using an inst amp IC that didn't have jfet inputs, which contributed to noise.

I decided to try again, this time using an instrumentation amp built from opamps instead of a single IC. I feel like my component selection was really good, and I checked and triple checked my schematic. But, I soldered everything together with a new board today, and got nothing but hum. I checked all my connections and all are solid.

Went back to my schematic, and found one flaw! I connected the wrong leg of the difference amplifier part of the inst amp, to ground. If you look at the schematic below, R-I7 and R-I8 connections are switched from where they should be. This makes the + leg of IC-I2.2 biased to the input signal, and the - leg biased to ground, instead of vice versa.

My questions:
1) Would this error alone cause buzzing and no audio to pass through (except buzz)?
2) Are any other huge errors present here that I'm missing? I've looked at this so many times, but I feel like I'm missing something else.

I appreciate everyone's patience, this is only my second venture into something built from scratch (not using others' schematics).

I'm looking at fitting one of these to a Cyrus DAD3 player which can be upgraded with a factory plug in QDAC module. It appears the pins to the QDAC match I2S and I have identified most of them on the PCM5102 module, photo below, but don't know what VIN is for.

In addition the QDAC has a pins labelled /ATTEN, TYPE and DOEN that does not appear to be supported on tis module - any idea what these are for?

And has anyone done something similar?

What I have so far is:

Pin Description QDAC pin
--- -------------------------- ----------------
SCK system clock X CLOCK
BCK bit clock BIT CK
DIN data input DATA
LCK data word WORD SEL

GND 0V
VIN ?

FLT filter select TYPE?
DEMP de-emphasis D_EMPH
XSMT soft mute /MUTE
FMT audio format TYPE?

A3V3 3.3 V supply

AGND analog ground
OUTR right channel output

AGND analog ground
OUTL left channel output

After 3 month I've finished my PGA2310 based preamp. Some technical data :

Digital part :
- PIC 16F628 running at 4MHz for volume and mute control and driving LCD display
- PIC 12F675 running at 1MHz for input selector
- 16x2 LCD with backlite
- PGA 2310

Analog part is based on the schematic from

This page . The only difference is that I used OPA2134 for input and output buffer.

Here is the front view

Hi, consulting the forum for some wisdom

Summer is over and time to upgrade the12vbattery sound system, searching some guidance on what is the best route forward

Currently using 3x tham15s, parallelled on a classD amp, doing only dj-gigs, and it sounds downright amazing after some proper tuning.
But I cant shake the sensation that I would appreciate more low end, and I am prepared to go 18", but I would like to discuss another option as well.

I am hounted by the thought: "If I just could find a way to squeeze 5hz more down low (+psychoacoustic bass enhancement algorithm) , MAYBE I would be satisfied with 3 more thams to fullfill my childish dream of 2x3 vertical stacks, instead of replacing the whole rig".

Did anyone try a 45hz bass boost with a steep HPF to sqeeze some extra low end on the tham15s? Or should I just accept that a 15"TH is not a 18" before I brake anything?

Would some barn doors on a vertical 3x stack boost low end, or just raise db of the entire bassband?

So I have been looking around for other options, and I am considering the Keystone and the Th18. From what I have been able to find, there are some reports that the keystone is a little more sensitive than the th18, wich is an important factor when limited amp power. Any other cab designs that should be mentioned?

I am a little concerned about going 18" in regards to amp power. Anyone got info about the powerfactor needed for 10hz more in low end with same amount of speakers at same volume?


Questions summarized:

1. Thoughts on a 45hz bass boost with a steep HPF to sqeeze some extra low end on the tham15s?
2. Would some barn doors on vertical 3x stack boost low end, or just raising entire passband?
3. Other TH-cab designs would be suitable?
4. Additional powerfactor required for 18" - 40hz and up in relation to thams15s 50hz and up?

Appreciate all inputs

Sincerly,
kris

does anybody know what this is and what it's worth?
Cheers ,

Rens

Hello gentlemen, I have a proceed avp that served me well for years. Messing with the buttons it showed “ record loop “ and frozen. How can I bring it back to normal status. I went through the whole manual but couldn’t do it.
Any help would be appreciated
Thanks
Salvador

Hi, I've had my NAD C325BBB around ten years. Pressed front panel ON/OFF last week, amber light doesn't go green. I've downloaded the service manual. Found out there is no +37VDC at CB53 (the power out 7-pin connector on the power board). However, on taking out the power board, all the solder on the +37V pin has melted, giving no volts to the main board. So I'm gathering there was a fair bit of current being drawn by something on the main board. I'm unable to find any short-circuit on the main board at the +37V in points, ie jcn R41/R45 and at R427. Has anyone had this sort of fault on these NADs?? Also reading another post of a NAD C320 he talks about notorious capacitors!! Can anyone enlighten me about them, please?? Many thanks for any help.