Hi!
I sometimes have fantasies...
This time, it would be an amp with the power-Switch on top of it.
I imagine something like a push-Button, D≈20mm, height >= 30 mm, that would switch with a fat „ka-chunk“...
Been searching on various places but haven’t found it.
Where could be a place to find crazy stuff like this?

Thanks!
David

Hi folks, wonder if you can help with a couple of service-related questions on a Trace Elliot Super Tramp guitar amp I'm going to work on for a friend.

1. Is there any service manual for these other than the schematics I already have? Would be nice to have voltages, biasing, tests, that sort of thing.

2. I saw mention of the Super Tramp having an EC83/12AX7 preamp tube. There's no tube in any schematic I've seen. What's with that?

I don't have the amp in hand yet, just a description that it sounds squawky or something. So I'll need to do the usual tests. Anyway, if anyone can help clarify those two points, much appreciated!

--KW

Gentlemen

I purchased but haven't received as yet a PA-3 preamp. According to what I have been told it has 3 5814A tubes. It is non-working and I would like to find some information before I tear into it to either gut it and start over or to repair it.

Frank

It looks like I may have to draw up yet another schematic. OH GOD!

Any help or information would be much appreciated.


Joe

Pictured are some of my collection of tone-arm plugs. The first 3 fit my SME V series tonearms perfectly. The OEM tonearm cable is the right angle plug. The last 2 are expensive custom replacements which are useless because of the sloppy fit. Any ideas as to why the variance in dimensions? The Jelco is made in Japan if it helps. The 2 silver ones are from E.U. but one fits and the other doesn't. Go figure.

Hi folks,

I'm having issues with the High cut filter push button switch on my Mitsubishi DA-R20. I've tried cleaning it multiple times but it still wants to be a problem child. I could easily just bypass it but would like to replace it if possible but I can't locate one. Any suggestions on a suitable replacement option? The svcs manual shows it as part M07461455 if that helps at all.

Thanks!

Hello, would an older Phillip's console tube amp be worth developing into a tube amplifier without console?

To no surprise do cheap, low quality gear come with the lowest quality power supply and shortest possible cables! So I am now the "happy" owner of a mid cable power supply that have to be on my table, way to near my scope and other gear.
Is it possible to buy / make a enclosure that reduce the EMI or maybe almost eliminate them?

First of all I'd like to say that I have no experience restoring audio, but I am pretty handy and up for a challenge. With a good explanation I'll be ready to go. I posted this question in another thread but there was no response, so I thought a new thread might get more attention. Also this is basically my first post and I might not know all the lingo. Anyway, here we go.



I have a Sony MHC-7900 system with Sony SA-H7900 speakers. The system has been collecting dust for the past twenty-something years. I'd like to revive them since it is supposed to be a great system, but the tweeters (Sony 1-504-388-11) in the SA-H7900s are very quiet. I already checked if it was an equalizer problem and it was not. With a flat equalizer there is hardly any sound coming from the tweeters. This problem is also shortly discussed in this thread, but that hasn't been of much help.


One tweeter was slightly quieter than the other. I took it apart and cleaned it following this youtube video. I first cleaned it with dish soap, which made a small improvement. Then I did it again with cleaning spirit, which made no noticable difference.


As far as I understand either the electrostatic foil is not conductive anymore or the high voltage circuit doesn't work. The fact that both speakers have the same problem makes me think that the foil is the culprit, not the circuit. For those that are interested, I found a service manual of this loudspeaker.

Does anyone know what to do next? Are there still replacement parts available? I'd love to restore this system in it's old glory. Thanks in advance!

The Pi is small enough to fit inside the DEQ and bypass USB/spdif conversion if direct signal connection is possible. There should be a jump in SQ.

Will the DEQ allow this if I'm prepared to forego all other external spdif connections and if so, how to go about it and any clock issue? Adding a separate Pi power supply is assumed. Thanks!

Hi,

While troubleshooting my Linn 2250 amplifier I found than one of the channels has a DC offset of 1 volt. Each channel has 3 TDA7293 chipamps in parallel configuration.

My question is, is there a way to determine in situ which TDA7293 is faulty without replacing all 3 chipamps?

Hi everyone I am planning on experimenting with transmission line subwoofer and was wondering if t line subwoofer is really worth the extra box size.
As far as I know t line has flatter response and slower rolloff so it would get deeper than ported.
We are talking about a box for cheap generic 12 inch subwoofer. I have some parameters for these drivers and i can provide them if needed.
I am on a budget currently and i already have these drivers and want to experiment with them until I can upgrade.

Has anyone ever replaced their own NiCad battery in their Tandberg 3001 or 3011 tuner and found a good replacment?

Dear all

have a pair of original Mission 753 which were working perfectly.

But I tried to do the usual tweeter-grill removal mod.

Seemed to go okay, but I noticed the fine copper wire around the tweeter came a bit loose. It doesn't seem broken though.

When I reassembled everything the tweeter doesn't work at all 🙁

I've tried reassembling several times, but no luck.

Does the copper wire need to be fully wound around the tweeter edge or is some of the wire meant to go into the groove in the 'base' (where the foam plug has a groove around it)?

I hope someone can help please...

Aikido Cathode Follower [ACF] Buffer

For 6DJ8, non White-Cathode-Follower configuration, do I:
1. jumper R5? (Y/N)
2. jumper R11? (Y/N)
3. Omit C5 along with C3?

It would be great to have these definitively answered, since that's the last hold up to complting this project!

Thanks in advance!

Just joined and new to forums.
Looking for info to build a reverb remote pedal for this amp. The socket is a TRS stereo jack and I don't quite understand why from the schematic. Does anyone have any info on this please.

My parents found the time to completely clear out their house during the current crisis and threatened to throw all of my old amplifiers, from back in the day, away.

I could not allow this and have taken possession of every bit of crap... I mean audio equipment I had bought as a kid and young adult.

Some of has gone straight in the bin, (Longmill EQ anyone? 😀) and some is worth saving.

I don’t know how I blew this one up, but it was gone good and proper.

The primary side caps were literally blown and the thing doesn’t even power up enough to draw any current from my current limited PSU.

There is a little spark from the caps charging but nothing else when the remote is connected.

There is 12v on the PSU FETs but no oscillation, I suspect a dead 494 but it’s a surface mount component and I don't have a hot air soldering station or any chipquik...

Could there be something simple that I may have missed to check first?

I have wanted to build the EL84 version for a while and scrounged up all the parts needed to do it while we are in lockdown here. The chassis is made out of bits and pieces of chassis and scrap. The HV transformer is a 300w 120/240v adapter toroid so it’s much bigger than needed. I used 2 low voltage transformers, 1 for the +20v driver power and +12.6v for the 12ax7 and a second winding for the -36v bias voltage. A centre tapped transformer supplies 2 x 6.3vac for the power tubes.
I have regulated 12.6v 12ax7 filament,-36 for the bias and +295 for the B+. I used the Power supply board and modified it extensively to produce the regulated voltages I needed. I also re configured the relay to use the normally closed contacts to hold the HV to 100v for The delay time which I set to 1 minute. For output transformers I used the Toroidy 8k UL transformer which I have had since ordering them along with the EL34 outputs for that BH version. These are also quite large, being rated at 40w.
Fitting all this in the chassis became a big job. I was also concerned about hum issues with AC on the power tube filaments and 3 transformers in the mix.
Oh! And I painted it yellow and brown. Looking through my paint supply I found black but wanted something brighter, to lift the mood during these stressful times.
I ended up attaching the RCA connectors to the front sides of the chassis rather than the top, where I have seen it done before. I always thought it would be awkward and in the way to have the cables coming into the top of the chassis so I tried something different.
Bias adjustment was another issue. I did not have room to mount a switch and meter like on the EL34. So I came up with using the 8 pin RJ45 internet connector to bring up to 8 wires to the side of the top cover. I then connect a network cable with the other end connected to a terminal strip and can easily measure the low voltage bias voltages. I still have 2 wires of 8 which could be used to monitor a divided down HV and -bias voltage. I will post again about the tubes and operating points etc used.

Hello,
I have 2 subs and both are not working, one is a def tech pf15tl+ and the other is a jbl venue 12, both have amp issues, have recapped the jbl with no luck and also replaced the filter caps on the def tech also no luck. Tired of plate amps, thinking of just buying a external amp to get at least one of these working, not sure what I need to do this and how to hook up to what is there already. I have been reading and researching alot but am new to this and would really appreciate some advice. Thanks

Hello all.
Has anyone know of a schematic that uses DAF 91,DL94,DK92,Df91 or some of them for a guitar amp.
I have a Roberts CR portable mains powered radio that I would like to convert

Thamks

Hi all, newbie here, still learning the ropes, and would appreciate a bit of advice!

I have a nifty little Steljes ML50HD, just cracked it open to see if a quick deoxidising of the volume pot would sort out a different problem, but then also noticed the GND screw and an empty GND spot on the PCB.

I presume the ground screw is grounding through the metal chassis, it isn't connected to anything else. Then I wondered if anything is supposed to be connected to the PCB GND? It sits on it's own just behind the phono RCA inputs. The power (DC input) is way across in the corner. Pictures attached.

Thanks for any help!

Hi. I have been away so long that did’nt remember my sign in info. So created new.

But here is my question. I have Technics SU-V900 power transformers, filter capasitors and heatsinks. Transformers secondaries are about 46VAC, so that makes quite high voltage after rectified and filtered. Caps are 12 000uF/71V

Do you have suggestion, what could be quite simple power amp schema for these voltages. I have found something, but don’t know how they sound.

First DIY project will be a Subwoofer, but ive not been able to source a budget plate-amplifier for a reasonable price in the UK. I need it to run a Peerless SLS 830667 and ideally would get a Dayton Audio SA70 70W, but they are only available on import via amazon, and shipping and taxes don't justify the cost. Any ideas where i could get a budget plate-amp? doesn't need to be a Dayton..

OK, after :
- The ULTIMATE 300B
- The ULTIMATE OTL6080

Now :
- The ULTIMATE KT120

Note : ULTIMATE seems to somewhat be pretentious, but it doesn't mean "The BEST", only "The LAST" for me, instead... L'ultime tentative... 😉

Like the other ULTIMATEs, it will be built in the same Hammond aluminium box :



The protoype looks like this below :

[/URL][/IMG]

The first measurements and scope examinations proved to be correct sans plus 😕 :



But far from amazing if I compare to the results given by my U-OTL 6080 😱 :



For the moment, except a 10dB NFB, I did not tried any other correction. I wonder if my STS AH50B output transformers (used) have not suffered... 😕

Here are their specs (AH50B and AH53B are nearly identical) - it's in French, but the numbers are understandable, fortunately :





As you can see, they are not "average" models, but... 😕😕😕

I'd be interested to see similar oscillograms of such kind of single-ended amp from you Guys, so thanks to post pictures ! 😉😉😉

A+!

Hi,

my Hypex quad UCD180 amp is humming.😡

This unit was build a couple of years ago but the humming only recently became an issue or more apparent when i added a minidsp 2x4HD.
But the minidsp does not seem to be at fault as the humm exists when testing the amp on the bench/kitchen table.

The amp consist of 2 smps400 power supplies each driving both an UCD180HG Hxr and an UCD180AD (with a modified opamp).


With the amps on; the test speaker (TangBand W3-871s) makes a barely audible hiss (no problem).
Once an XLR-interlink is connected to the chassis the humming starts, touching the interlink in the chassis reduces the humm.
When using my XLR to RCA interlinks, touching the male pole of the RCA amplifies the (50 Hz?) humm extremely.

see video

The weird thing is that with the mindsp connected the humming is intermittent.
It sometimes builds up and can be removed by touching/hitting/shaking the minidsp 😕

I have to add that the amp is normally not connected to an earthed socket (1980 building code). Using an earth socket makes humm less but does not remove it.

So what did I do wrong making the amp?

I've had time to tinker for the first time in a long time. I have been working on an amplifier in the style of the linked patents, which has a linear error correcting amplifier working in tandem with a switching amplifier.

US Patent 4,523,152
US Patent 5,905,407

I implemented the IR2010 gate driver after the IRAUDAMP9 gate driver example and ran into some unexpected behavior. When the switching part of the amplifier (disconnected from everything else) has no logic power supply, but does have its main supply, its output was going high or periodically oscillating to high (brief blips at 50Hz or 120Hz intervals). After much debugging, the only thing that fixed it was to eliminate the bootstrap charging resistors which charge the high side floating power supply before the logic supply takes over via the bootstrap diode.

Is anyone familiar with this problem of self turn on in the absence of a logic supply? I can't tell from the datasheet whether the IR2010 outputs are specified to be high, low, or open in the absence of its logic power supply.

In my design I have a 10kOhm resistor to floating return on the output of the transistor buffer, but I omitted any resistor to return on the input to the buffer. I thought that might have been an oversight, and soldered in a resistor manually and still ran into problems with self turn on. This happened with that stage loaded or unloaded.

The switching part of the amplifier is now happily working without the bootstrap charging resistors, and the switching waveforms do not have excessive ringing on the oscilloscope. I'd like to try to fix this though, because now there is a 100uS long large voltage blip after turning on the amplifier due to the bootstrap being uncharged, which wasn't there earlier.

The gate driver circuit is attached, the resistor in question is RB57, which appears to causes unwanted turn on in the absence of the logic supply when the main supply is active.

Self-Assemble Speaker Kits – PBN Audio

they seems to be only simulated crossover on measured speakers, but i don't see the real and final measurement of cmplete system.

have someone of you experiences over these kits, are they reliable ?

thank you

I spent considerable time replying to a post over a few hours & when I pressed the submit it said it had timed out & to press the back button, re-load the page & re-send. BUT, all my work had disappeared. - Where did it go & how do I retrieve it ?

There isn't a parasound or repair dealer in my state 🙁

Here is what I have tried so far or diagnosed
-Shake it and smacked it, no effect
-checked and removed fuses and no luck, fuses are good
-I can hear a relay click over when it starts up
-The amp doesn't go into standby
-The right channel works and it will work as loud as my ears can handle my speakers
-The left channel will work at lower volumes but when a high pitch tone hits then static will appear. When I start to increase the volume the channel becomes nothing but static.

I have access to a digital multimeter and I think one of the transistors has went out but I need help on figuring out which multimeter went bad. I set the dmm to a continuity check and got resistances across across the legs.

here are some pictures of the amp, they are 1600x1200
http://webpages.charter.net/ajbertelson/diyaudio/top01.JPG
http://webpages.charter.net/ajbertelson/diyaudio/top02.JPG
http://webpages.charter.net/ajbertelson/diyaudio/transistors.JPG
http://webpages.charter.net/ajbertelson/diyaudio/centertransistors.JPG
http://webpages.charter.net/ajbertelson/diyaudio/transistorscloesup01.JPG
http://webpages.charter.net/ajbertelson/diyaudio/transistorscloesup02.JPG


This is my first time working with amps and I know I am playing with fire but I was wondering if I would be able to get some help in figuring out what went wrong. I am trying to learn about this stuff more.

This is a new thread specifically regarding my version of the Murphy Corner loaded line array using Vifa TC9 and stealing ideas from both RA7 and wesayso's line array threads.

Mine will be somewhat unique in that I can build them into the walls themselves so I can get the drivers as close to the corner as possible while also optimizing the enclosure volume.

Still in planning stages, but here's what I'm thinking so far.

- Power through 2 DIY NCore 400 monoblocks
- DSP through either miniDSP or whatever may come with the HT receiver I end up purchasing... perhaps an XMC from Emotiva.
- I have two Stereo Integrity 18' already with the intent of an IB subwoofer but may not use them if I can EQ the arrays to sufficiently represent HT bass.
- Will be building in surrounds into the ceilings (Atmos) and walls
- Room is about 11' wide by 20' deep. I'll throw up a sketch at some point.
- Sources will be a variety of things from SACD to vinyl to CD to HTPC.

And as no thread is complete without some pictures, here is where the remodel is at the moment:

The old room is gone and here we have some jack hammering to reinforce the foundation:


One interesting tidbit...



Our house was full of old knob and tube wiring. There are a few spots where it appears the wiring got super hot (short?) to the point of charring the nearby wood! Not sure how this was discovered as it also appears as if some tar or some other insulating substance was applied on the wires. In any case, we're rewiring the entire house so this won't be an issue again. While I'm on the topic though, is there anything I should specify for the HT room itself? I'm not a huge believer in power conditioning or whatever, but thought it would be worth asking.

Finally, in case you're curious... here's a shot of the second floor totally gutted:


This is through the kitchen into the two rear bedrooms which happen to be directly above the first shot.

Thanks in advance for all your help to come!

I hate starting new threads for a single question [EDIT: after posting this, I laugh at my thought of it really only being one question], but I can't seem to find info upon searching...


I plan to use the attached circuit (or a variation of it) in my new build. I'm starting this thread because it might help someone else that isn't interested in the amplifier.

Ignore the power supply (I'm going to tap off of the existing B+).

I want this meter to be "peaky", I assume C2 makes the meter more normalized/smooth? If so, removing it should work?

Is D1 there to make the signal DC? W1 wiper connects to the top of R2. If I changed the 100k pot to 1M, would I have to adjust the capacitors to compensate?

Why can't I just drive it like a normal triode? I will have a 1:20 gain stage to boost the level from line already... Can't I just put a biasing resistor on the cathode and feed it AC signal?

W2 on the cheap 8$ VU meter boards almost always smokes after 5 minutes in my experience (literal smoke). Replacing it with a 2W 500k part just showed you only really need a ~100k part for adjustability.

I want to build a push pull amp with the directly heated tetrode 2E25 operated in triode mode. My question is, should I connect the beam plates to the cathode?

I have a Musical Fidelity M1HPA and I see my woofers move slowly back and forth. If vol pot is turned down the movement is worst. Maybe 5 mm. When itøs turned all the way up, there is no cone movement.

What can be wrong?

Cleaning the garage... For sale 4 Dayton Audio DC180-8 absolutely NEW.
One of them measured and then installed in cabinets. I had no time to do a crossover and this projet is cancelled. Never used.

Selling in pairs:
1 pair: 40€
2 pairs: 70€

I could trade for... i don't know, but I don't want to put money.

Thank you

Greetings,

A few months ago I had something dreadful happen in my life and it has caused a steep decline into unhealthy obsession. What occured was this video, showing up in my recommended feed. Oh boy, the spiral.
Then he goes ahead and releases another video and things only get worse.

So naturally... I decide to start building my own DML Speakers, which the first iteration looked a little like this:



But that wasn't good enough, they were rediculously large and the build quality was really only to a prototype/proof of concept level. I needed something better. Not only that, I hated the design of the passive crossover network, it was as if as soon as I introduced it the life was sucked from the panels and it's spine tingling sound dissapeared.
Alas, I chose to keep the network for the time being, add a tweeter section, and carry forward with the reconstruction.

As it stands, the full project is yet to be completed, though I'm not far off I don't think.
DML Speakers: Fully operational, just a couple items left until completion
6 Channel Amplifier: Linear Supply prototype tested and amp boards assembled.
Linkwitz Reily 24db/oct 3 way stereo crossover: Constructed, needs rewiring and testing.
Preamp: CNC phono preamp & Mussify 15-0-15 supply pre-existing, k5169 Preamp Kit needs assembly, and Case needs building too. So just the pieces :/

Alrighty, picture time:

DML Construction
Drivers are da175-8, DAEX32EP-4, and PTMini-6.
Turns out these look like big IPhones, oh well, Steve Jobs would be proud.

Passive Crossover v1

Passive Crossover v2














Current Evolution:


Active Crossover:
Used VituixCAD to model the passive network, as well as the crossover points for this board. Sellers on Aliexpress provide these with custom ranges, they change the cap and r values around to meet the need. Construction quality seems high, but what would I know (shrug?).








Preamp:
Just Image these two doods together inside a case that looks like the crossovers 😛



Power Amp:
Same deal with the preamp, just imagine them in a simlar case as the crossover 😛




I have no experience building speakers or hi fi gear, but I've always been the type to void warranties out of morbid curiousity. So it seems I know enough about electronics to be dangerous, hence I invite discussion, recommendation and critique. Hopefully I can find new ways to improve upon the design.
I haven't taken many photos or made great descriptions so if you've got questions, I'll answer em.

I'll keep updating with progress.

I bought the Boyuu A9 el34 tube amp from China. It will not play as loud as my cell phone. I replaced all tubes and that did not fix the problem. I think he may have sent me a 220 volt instead of 110 volt. Argued with him for 2 months and finally gave up. Any help or a point in the right direction would be greatly appreciated. Cannot send it back.

Hello,

I am looking to have a 12V trigger input. I am trying to find info online about a 12V trigger specification but it seems that different manufacturers do different things.

Anyway, my question is:
Is 12V trigger typically 12V for on and open circuit (high impedance) for off
or
12V on and 0V (driven to 0V) for off?

Thanks;
Leo

Follow this excellent audio amplifier, designed by me based on the original layout so good and reputable Douglas Self.

The main changes and additions were based towards greater power, higher working voltage, adjustable gain, bootstrap option on and off, using more current components and some minor changes of values ​​in order to work well with these changes.

Have a great gain, I suggest using a well-designed and well filtered power supply, especially if it is with common transformer.

follows:









Sorry, the images below are the guidelines in the Portuguese language, because they drew up especially for nosos national forum, but i guess you can understand:




IMPORTANT FACT ABOUT BIAS ADJUSTMENT:

BIAS ADJUSTMENT MUST BE PERFORMED AFTER THE CHOICE OF MODE OF OPERATION (BOOTSTRAP ON OR OFF), AND MUST BE redone AGAIN IF THE CHOICE OF OPERATION MODE IS CHANGED.







Below is a shield against the DC outputs, I used automotive relays because they are cheaper and bearing a larger chain:



Below is a rectifier plate with soft start built for those who want to make with conventional transformer. This system couples the capacitors until they've been previously loaded via load resistors:





Below are links to download the respective PCBs PFDs...

Complete amp:

https://mega.co.nz/#!mRZV0KhI!N2cQnUwLUK3nGqLudaFRfA5DaSBpAIVWrVvrBD6AFwY

Protector DC:

https://mega.co.nz/#!zUowlSCA!CZehRxETRFc7XJ4oCsXj1Q8n8CJXhmGjAx49uyZB6_I

Rectifying with softstart:

https://mega.co.nz/#!uZogmJaA!Aydvjy1sJKOIjma4PUscv1evev0DkARO0OCG1RQRRc0

Follows a video that demonstrates the immense sound quality of this amp here. I beg you not notice the mess on my desk, the power supply is improvised and inadequate:

Teste de médios / Agudos (Cindy Lauper) - Debunker - YouTube

Friends, please excuse my horrible English. Any questions, we are here ...

Hello mods
I am trying to reply to a private message but after I click on send, my reply text disappears. I dont know therefore if it was sent or not.

Any ideas?

Thanks

Tapping ballanced XLR to RCA?

Is it possible to make a tap on balanced XLR cable to another RCA output but still retain the balanced "noise free" on the XLR line?
I've got one balanced XLR output to amp on my mixer but also need to run it to another amp with RCA connectors.

Selling my Mark Johnson "Noir" Class A amp.
Smooth ALPs Blue Velvet volume control.
Works well with HI/Low impedance cans.

Price to build approx $200. Will sell for $200.
Split shipping cost so add $10 to price.

You can read my review here:
Mark Johnson Noir Class A Amp (aka T2) - Do It Yourself (DIY & Mods) - The HEADPHONE Community

Build Thread:
https://www.diyaudio.com/forums/hea...or-headphone-amp-class-single-150ma-bias.html

The Noir is on the bottom of this stack:

I noticed a hum and pulsing noise coming from my DAC even though it wasn’t on. I speculated it could be DC on the AC line. I tracked it down to a heating pad on the circuit. While I have no idea how accurate my testing was, I measured 10 millivolts with the heating pad off and 200 millivolts with it turned on. With it off the hum and pulsing stopped. That’s great because there’s nothing wrong with my DAC. Can anyone tell me definitively whether I’m somehow damaging the transformer when I use the heating pad? Would this cause a degradation in sound when the DAC is in use? Is there a relatively easy was to remove any DC on the AC line? Thanks for any answers you provide.

Ironamp project video posted here:

https://www.youtube.com/watch?v=FZymAeaVsAg

I hope you enjoy it. 🙂

I updated the captions if you want to try Youtube's translation option - should be funny 🙂

Hi Guys

I'm selling 4 pieces of Hovland Musicap 0,1µF/400V capacitors. 60€ including shipping.

Regards

I have 2 red tops crossed swords and 2 blue top .
I bought these from a reputable high end Hifi and tube dealer in Holland ( receipt provided)
I am assured by him and other tube aficionados that these are genuine.
I paid €200 euros for the 2 pairs so I’m asking £200.

For Sale one LME49720HA MM Phonostage and two Salas Shunt power supply (negative and positive).

The phono stage is based on the project from LME49720 datasheet. High quality components (Nichicon for audio, WIMA, ELNA low ESR etc.)

What you see in the picture is what you get.

The price is 135 Euro + Shipping to EU only.

Hello I have a Audio Note Kits (ANK) Canada Dac 4.1 with tube output stage with two 5687 tubes.
For tube rolling I bought this socket from eBay
"1PC Convert Tube Socket 12BH7 (Top) TO 5687 (Bottom) Tube DIY Adapter Socket"
1PC Convert Tube Socket 12BH7 (Top) TO 5687 (Bottom) Tube DIY Adapter Socket | eBay

After using this socket with 12BH7a tubes instead of 5687 and starting the DAC big distortion in sound started with very little audio signal. The tubes got very hot. I immediately switched of the DAC.
After I removed the adapters and just used my original 5687. Still the same distortion and my tubes got very hot.

Did I destroy the DAC?
Can anyone of tube experts help please?
The Tube output is connected for I think 12volts heater supply to 5687.
So what I need to repair? Is main power transformer burned or I have to change some capacitor?
Thanking you in advance😕

Hi
i have a raspberry pi 4 and Khadas tone board
i want to power the pi via the original power supply but i would like to give the tone board a low noise supply to improve the sound .
what i want to know is if i split the power from the supply and feed it into a buck converter board set at 5v to 7v out to feed the tps7a4700 ultra low noise regulator board set at 5v to power the tone board ? would this be ok ? see pic
the buck is there to give the regulator a bit of voltage to drop
CamScanner 05-22-2020 22.06.23_1 by glenn jarrett, on Flickr

These are 7 pin tubes, do they fit into 9 pin sockets?

Hi,

I'm building an amp that will use a Hypex SMPS1200A400 power supply (DIYclassd.com), and I want to add a soft start module, also from Hypex (DIYclassd.com) for in-rush current protection as well as standby functionality.

The soft-start module will make it relatively straight-forward to add a push-button to toggle the amp between standby and on. I would also like to add a 12V trigger, but Hypex told me that their soft-start module doesn't support that feature.

Does anyone here know of a way to rig something up so a 12V trigger could still work with this soft-start module? I'd prefer to use this module as with it the power supply would only draw 1.2W in standby mode, whereas without it, it will draw 9W in standby mode.

And otherwise, is a soft-start module really necessary? I'm pretty new to working with electronics and would like to be able to put this amp in standby mode or switch it on with a button on the front of my case, and use the 12V trigger to turn it on/standby from other components in my system.

Would appreciate any ideas 🙂

What would be a good supply to power the 3.3v this diyinhk xmos board requires ?
XMOS 384kHz DXD DSD256 high-quality USB to I2S/DSD/SPDIF PCB - DIYINHK

I'm currently using one of these
low noise Pre-Amp / DAC power supply MJE15034 TL072 Regulator based on STUDER 900
to power a SRC at 5v and another at 6v feeding an AMS1117 board to power the xmos.
5pcs DC 5V to 3.3V Step-Down Power Supply Module AMS1117-3.3 800MA LDO NEW 700850568148 | eBay

What would improve on that ?

Hi everyone, I've been a music and hi-fi fan for over forty years. A sound engineer friend recently introduced me to the wonderful world of DIY performance upgrades and I have been cheerfully tinkering with many old CD players and amplifiers, giving them a new lease of life.

For me it's been about bringing equipment back so someone else can enjoy it and also funding the upgrades on my lounge system! I've just completed a full restoration on a Sansui SR222 MkII, including building a brand new plinth and base from MDF. A trip down memory lane as one of these beauties was my first piece of real hi-fi. A saga for another day perhaps.

Anyway, I look forward to hearing all about your adventures in this wonderful hobby and learning how to do more than just recap amps and fix broken CD mechs!

Take care everyone.

Mark

This is one speaker that I have not seen cloned (or facsimiled)

Spica TC-50 (woofers 8 ohm data)
Spica TC-50 Product Information, The Spica Speaker Enthustiast


Crossover
Spica TC-50 Crossover, The Spica Speaker Enthustiast

Speaker Replacements: Madisound Speaker Components

"Spica Speaker Replacements
Spica TC50

The Audax tweeters used in this speaker are available again! The new tweeter is the Audax TW025A2 tweeter, replacing the old part number of HD100D25. The woofer is the Hif 17JVX 4 ohm and we don't know of any similar speaker to replace this driver. There is no fix for the woofer that we are aware of. Bad woofer = junk speaker."



I think this is close to the Audax.

Visaton W170s (vas? difference)

Visaton W170S-8 6.5" Woofer with Treated Paper Cone 8 Ohm

Visaton W170S-4 6.5" Woofer with Treated Paper Cone 4 Ohm


Aside from an exact replacement woofer, what are the important parameters for a substitute?

TIA
-Chris

Hi,

Please look at the schematic.
This is presented as a clone of REDDI DI box in a different forum.
The pot at the output will short the transformer at the extreme position.
Am I missing anything here?
Thank you
Glass painter

I've recently started designing PCBs in Kicad and would like to know of any people or companies who make circuit boards that you'd consider exceptional examples or even interesting examples of design styles. I'm spending plenty of time reading about design methodology and I'd like to supplement that by looking at a variety of implementations.

Luxman emphasize their circuit boards and their maybeslightlygimmicky curvy lines, Audio Research has a sort of stylistic signature, Audio Note UK certainly does, Lavardin does some pretty patterned ground planes, Aavik likes planar inductors, and there are many examples of creative component and case mounting.

Whose boards do you consider exemplary?

I have been looking at some of the measurements Amir has been performing over at audiosciencereview.com with a Klippel Near Field Scanner

There was one for the JBL LSR 305P MKii speakers and I happen to have a pair so I downloaded the measurements to have a look. After a bit of fiddling I got the On Axis and Listening Window responses into REW. They are very similar with a little bit of a rise in high frequencies for the on axis response.



A couple of people had made EQ corrections for them over at ASR so I thought I would try my hand at it.

I used manual EQ to flatten the curve as much as I could without micro managing it too much, the result was much flatter.



There were still a few minor bumps that would be difficult to try and improve on with basic PEQ so I started on an inversion based EQ.

I used REW to invert the Listening Window response using 1/A in Trace Arithmetic. This isn't very usable as it is with the huge boost to flatten the low rolloff.



There is a way to use DRC_FIR to apply a target response to a dirac pulse so you end up with an impulse from a text file. I exported the measurement as text and only used the portion between 67Hz and 4K to avoid the excess boost and not correct above 4K as apparently the measurement is not valid over that point due to an error in the operation of the Klippel, this speaker was the first test measurement.



A couple of edits to the text file to make it work with DRC and this is the filter that came out. It corrects the measurement to flat between 67Hz and 4K very nicely.



Here is a comparison of the basic REW PEQ and the DRC filter. My manual filter is very similar to the inversion so I'm happy I did a good job there.



I have attached an MDAT (LSR Klippel EQ.zip) of the different steps in case anybody wants to look. By selecting the Listening Window response and the EQ tab the REW EQ settings can be exported if anyone wants to give it a try.

I have also attached the impulse correction filter as a zipped wav (LSR.zip) for use in a convolver. There is a slight gain of about 2dB add a reduction if you need to.

I haven't tested this myself to see if it works as I don't have the speakers set up at the moment. I will test it out at some point and report back.

Hello!

I need some help regarding the repair of vintage amplifier. When I replace the output transistors 2n3055 or MJE 3055, they burn out. Also, what is a good replacement for the driver transistors?(schematic down below)

Best Regards electronicsman

HSR 48 shema - Google Search

I have one of the later (TOG) Cyrus Ones.
It has been “upgraded” before I got it, back in 2008 or so.
However whilst we’re all under lockdown, and as the front panel badly needed repainting anyway, I decided it could do with a look over, including having a proper look at the electrolytics. The onboard polarised caps were all Panasonic FCs and looked in good order, so I left them alone.
The original PSU caps (which I believe were rather nice slit foils) had been replaced at some point by Nippon Chem Con KMG ones. Since Cyrus spec’d slit foils, I decided to return it to spec.
The original NP electrolytics had also been replaced before I got it, by ones from SJE (Sang Jing Electronics).
I decided to replace the main PSU caps (with 10,000uf slit foils from DNM) and replace the NP electrolytics (with a mix of Nichicon Muse and Elna from HiFiCollective). I did think of replacing the lower value NP caps with Poly caps, but I would have been tight for space on the board, so stuck with NCs.
Results are spectacularly good. I’m delighted and would thoroughly recommend these components to anyone looking to keep their old Cyrus One running.
Paul

Hi, yesterday i found a couple of speaker in my storage room. It doesn't have any specs written on its box other than W3-2001S. I have attached some pictures of the driver. It measures at 3 inch. Do anyone know who manufactures this speakers an or know the specs? Any help would be appreciated. Thanks!

Please help me close this thread: chipAMP with flat TF beyond 50KHz with any inductive speaker?

...and also let me know how to do such requests-to-admin more simple, if any possibility exist. Please advise.

Thanks,
Ionmw

Only two ports , input and output , base on a switch IC

What I mean is, how important it is to match (hfe) output transistors on a class A/B power amplifier, if they have emitter resistors.

Attaching the area around TL494. One side drivers burn and burnt the board too. It is soundstream tx2.1500 amp. I cleaned the area and changed TL494 removed all the power fets from board. Switched on the amp to see oscillations. Found no oscillations. Pin 16 is high 3.5v . It is connected to optocoupler and pin3 through diode. I removed the diode and optocoupler still getting 3v on pin16. And pin 3 is 3.5v. Getting oscillations but duty cycle is far different from normal oscillations.

Hi all ,

I am restoring a PIONEER SA – 810 tube amplifier for a
friend of mine , but I don’t have the schematics , I could
not find anything in Google or Yahoo .

Please , can anybody help me ??? As the service is for
my friend ( and FREE .... !!!! ) , I can’t spend money , so
I need your help guys . Any file format will be wellcome !!!

Hi gingertube ,

I was reading an old thread ( 11-03-2005 ) , where you
had said that you have a CD with all Pioneer tube schema-
tics , in .pcx Photoshop format file , and the SA-810 schema-
tics was there . Do you still have this CD ??? Can you help
me ??? It’s not possible to make contact with your e-mail
through the forum , because it is not available . If you read
it , please reply !!!

Any input will be wellcome . Thanks in advance for all .

Carlos

Hi,

I have recently studied the principles of some well known commercial power supplies, such as the Paul Hynes SR-7, Uptone JS2, etc... , and it appears that the quality of the transformer has an impact on the final result (sound quality).

As I am not an expert in the transformers domain, I try to identify what are the criterias that make a transformer better (sounding) than another. I know a firm that can manufacture custom transformers, Toroidals and C-core.
Of course the Transformer is not the only part to make a difference, but for now I just focus on the transformer.

The cost is not really a concern for the time being: I just try to identify the criteria to care about.

The P.S. should be able to deliver 10A on 12V, with 2 rails.

So:
-Toroids or C-Core ?
-And of course what are the other things that could be asked to the manufacturer ? screen, what quality of materials, etc...

Thank you for your replies

Recently I had a couple of stylii send off to be imaged as a favour. Both AT microlines, but one well worn (audibly so) and the other under 10 hours. After sticking them under the microscope a track was recorded with each so there is a record of what a worn out stylus sounds like. But we were mulling what sort of audio analysis might be useful. If I can work out how to operate dropbox I'll post links here but in the meantime any ideas what might be of use?

Hi
I ordered some speaker ports for a smallish desktop design, however on receiving the ports I’ve found the actually taper from approx 41mm at the front to 38 at the rear over about a 100mm length.
So the question is which measurement do I base the calculations off the opening @ 41mm or the rear of the port @38mm or do I take an average between the two?
Thanks for any inout

Hi,

with standard UL configuration, where screens are connected to the same voltage supply of the plates, the higher the signal at the input, the lower the plates go compared to the screens (more secondary emission?) but in any case screens will never go negative.

With tertiary windings, like for 6550 where to maximize power you need to connect plates to 600V and screens to 300V, or GU50 with plates at 900V and screens at 300V.

Now if you have classic 43% UL connection, and the plates swing down to 50V, the screens will swing:
- 6550: (600-50) x 0,43 = 236,5 Vp
- GU50: (900-50) x 0,43 = 365,5 Vp

So when the plates will be at 50V the screens will go down to:
- 6550: 300 - 236,5 = 63,5 V (still positive and close to Va)
- GU50: 300 - 365,5 = -65,6 V (negative voltage)

So the first case is ok, there will be almost no secondary emission I would say, and screens should have no issue, but what happens on GU50s with negative voltage on screens?

LTSpice simulations go into oscillation, but what will happen in reality?

Thanks

I have a pair of 10" subwoofers, on an engineered hardwood floor, over slab-on-grade concrete. Currently I have them sitting on Auralex MoPad foam isolators. I have threaded spikes in a drawer.

I am not keen to use the spikes because in the past they have damaged wooden floors, even when mounted in cups. Also, installing them is a pain in the ***.

What does theory say I should use, isolators or spikes? What is your personal experience?

Is it any good
#Aliexpress US $63.19 21%OFF | Nobsound Mini FU32(832A) Valve Tube Amplifier Hi-Fi Stereo Preamp Desktop Tube Headphone Amp
Nobsound Mini FU32(832A) Valve Tube Amplifier Hi Fi Stereo Preamp Desktop Tube Headphone Amp|Amplifier| - AliExpress

I don't have a specific purpose. I just think it look Uber cool. Could it be used as a buffer for pascal spro2 module. Or only as headphone preamp? I also have have a Kt120 class A amp that also need some fun stuff

Anyone have a copy of this service manual? Pacparts doesn't sell them. :/ (Likely due to the recall.)

I have a decommissioned (recalled) unit that I'd like to be able pull some parts from for testing another amp. The parts list from the service manual would make identifying parts much easier.

It's a long shot but does anyone have a wiring diagram for a denco TDO 2 tape recorder oscillating coil ?
Thankyou colin

I thought it would be fun to have a new project during the current covid-19 work from home situation so I picked up a pair of "custom" speakers cheap that were made from Rectilinear III Highboys. After doing a little research about speaker design I realized I was in way over my head.

I've got tools and I'm handy with wood and steel but know very little about speaker design or audio wiring in general.

So what here is what I am starting with:



Yes, those are the original tweeters and super tweeters covered over with silicon caulk. I know, the horror. I have enough OCD that it wouldn't let me leave these as is even if they sounded perfect.

One speaker sounded OK (not great, but OK) and the other one was was flat like when the caps have gone bad in the crossover. I took them apart annd this is what I am left with:



Box outside dimensions 31 7/8"H x 17 7/8"W x 12"D (baffle is recessed 7/8")
Made from 3/4" panels. There is a 3" foot on both speakers.

The baffle is easy to remove and I plan on replacing it with the new configuration.

I calculate the volume at 2.77 cubic ft (78.5 Liters) before subtracting volume of bracing etc.

The salvageable components I pulled are:
Dayton Audio DC300-8 12" woofer 8 Ohm with
Peerless 821639 2" Poly Dome Midrange 4 Ohm
JAMO 20134 1" Soft Dome Tweeter 8 Ohm
all tested and working.

So my first question is are any of the drivers worth re-using? I'd like to at least re-use the woofers in the new design as long as they are not dogs.

Thanks.

Hi,

I have a Berhinger ADA8000 that the mains transformer has burned out. Anybody knows where I can get a replacement? I read some threads and seems that it's a common problem with these units.

Thanks.

I have an Xtant 3300c in my Camry, and I never bothered to get it set up right. I always had to turn up the volume on my deck too far to get the volume I wanted out of the amp, and my speakers are of reasonable efficiency. Because of that, I'd like to see if adjusting gain settings will help.


The gain jumper for the two front channels is set to the 0 setting. I'm not clear from the installation manual what that means. What is the gain for this model amp when the gain is set to 0?


Also, what's the difference between that gain jumper and the rotary gain pots for the front channel?


Can you folks recommend a procedure for setting gain properly on this amp, both jumper and rotary pot controls?


Thanks

Does anyone make a plate amp for powered speakers that has both wifi capability AND an active crossover?

Dayton Audio WF60PA has the wireless. Hypex FusionAmp FA122 has the active crossover. Any product have both?

TIA.

I've run a few searches and can only find one reference of the LM3886SMPS board.

LM3886SMPS | Connex Electronic

LM3886SMPS Stereo Amplifier Module 2x 60W 4 Ohms LM3886T - Audiophonics

All I can find is a picture of a partially installed board:

http://www.jkwynn.co.uk/Pics/LM3886_Lashup.JPG

I am in the process of finishing a set of Alpair 7.3s for my desk set-up and am currently running a 2xTPA3118d2 amp with a 19v 6a power supply.

I was about to pull the trigger on an ICEpower 50ASX2SE and a case from Ghent Audio until I came across the LM3886SMPS. From my understanding, both amplifiers are easy to assemble, the only major difference being that the LM3886 requires a heat sink.


Could anyone offer any advice on which board to purchase, I would greatly appreciate the feedback.

So, I found a power amp, specifically this one:
STK4133II WITH BOARD - Integrated Circuit - KSP ELECTRONICS
(Yes, with the board)
I searched the web but didn't found any datasheet that explaines what are those 18 pins do or even better, where shall i connect the 9 coloured cables of this board.


Does anyone have any clue?

Anyone know the value of these resistors ?

They are all discolored and are way out of tolorance .

And know why they may have burned ?

Hello!

I have a Heathkit AR-15 receiver. I recently began having this problem: The volume control does not reduce the volume to zero, on one side only. The right side.
This started after I had the control way up high, because of a Passive Volume Control I inserted after the “Tape Monitor” output and the “Tape Monitor” input. I was using an external volume control to control volume, so the actual volume control on the receiver was turned way up – to the maximum level I figured I’d ever need it. Long story – with a passive volume control I was able to control other devices that were being fed by the Tape Monitor output as well as the receiver itself.
I can’t imagine why that would cause the problem I’m having but it seems like it did. I don’t enough to zero in on what happened when I skewed the volume in that way. I’m stuck at the cause-and-effect level, without the knowledge to go any further.
So the actual problem is, that while the volume in the left channel is reduced to zero by the control, the volume in the right channel hits a plateau and will not go below that. Not even the “balance” control can reduce it.
(NOTE: the Passive Volume Control has been removed and the only volume control being used now, and described here, is the one proper to the AR-15.)
After maybe 20 seconds or so, there is a “null” spot in the rotation of the volume control potentiometer where the volume in the right channel – as well as the volume in the left channel - is almost zero. But that spot is not where the potentiometer is at the zero spot; it’s a little bit after. In other words, at a place where some minimal volume would be expected.
I was willing to let it go at that, since I’d never really need the volume to be that low. So if the receiver powered up at that volume level it wouldn’t be a problem.
The control starts to work as it should at that point and from there on up.
(to re-cap: below a certain point in the Volume Control potentiometer’s trajectory, the right channel sticks at a certain volume and there’s no way to cut it out. Even the balance control has no effect on it. Above that point the volume goes up and down as it should, following the volume control.
BUT if I set the volume control at the above-mentioned “null” spot where both channels are almost zero, and then turn the unit off and back on again, the right channel comes on quite loud. After a short time, well under a minute, the volume begins to drop – back to the almost-zero spot again.
I thought it was the volume control itself so I replaced it. To my dismay, the problem is still there.
In my naïve way of seeing things, I have isolated the 10mfd capacitor that comes after the volume control and before the final two amplifying transistors in the pre-amp and/or the 10 mfd capacitor that intervenes between the pre-amp and the amplifier as possible culprits. My reasoning is that, since capacitors charge, one of those two, or both, capacitors might restrict the volume while charged but, after the unit is turned off it (or they) would discharge and no longer restrict the volume.
I don’t know if this theory has any validity. What I don’t know is how or why a capacitor would be used to restrict volume. So I’m in need of a more knowledgeable opinion. There may well be some other culprit in the current problem, and I am curious to know what it is.
Can someone help me out? I’ve drawn circles around the volume control and the two capacitors I mentioned on the first attached file. The second one is the entire schematic for the AR-15.
Well, that was my plan anyway. Maybe you can help me figure out why this website wouldn't upload my files. I guess th



I’d appreciate someone’s more knowledgeable analysis. Thanks in advance!

bob