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TO-3 SYMASYM

Hello guys sorry if I already ask this question but is been a long time is about R36 and R16 they are 499Ω both of them this mean presicion resistors? 1% tolerance or they are in fact 499Ω seems a silly question sorry about that ok a precision resistors of 500Ω can be placed right?
 

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Symasym PCB and parts

Hi guys,
I have a set of un populated red TO247 PCBs and one set of populated red TO247 PCBs.

Also have lots of parts for building amplifiers so I'm thinking about donating some to the DIY community.
Only problem is that I hate posting stuff!
Anyone around London interested in building new amp?

Cheers,
Vlad
 
Hey,

i know that its not the easiest task to troubleshoot from distance...
But i am kind of stuck with my problem and made at least some measurements ;)

I build a few Symasym and one Black Beauty has started causing problems.
They appear randomly as audible noise just like a broken, scratching potentiometer (no hum!).
The funny part is, i dont use a potentiometer but a fixed voltage devider (Signal comes from a sound card)

One Black Beauty works fine. The other one ... misbehaves.
I checked: signal line, idle current, bad soldering, grounding, signal shield


I made some measurements at the speaker ports that you can see in the pictures.
Sampelrate is 10kS/s @ 12bit for 10 Sekonds. Samplerate is a little too low.. but i guess you will see the problem anyway.
I put a Colormap on top to give you an idea about the amplitude content at low frequencies.
And a good measurement for comparison (Amplitudes may differ)

I would be really greatful for your ideas... what might be wrong... where to look.

Sammy
 

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Gentlemen, I have 1 spare pair of SYMASYM 5.3 left together with a dual LT3062 PSU (for the SYMASYMs frontend-PSU, if you like).

I offer you the 3 PCBs for 22€ unregistered shipping (PAYPAL fee is included).
If you are interested - tell me.

Regards - Rudi_Ratlos
 

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