Stax SRM1-MK2 rebuild and bias
May 19, 2019 at 1:49 PM Thread Starter Post #1 of 2


New Head-Fier
Apr 10, 2019

I just finished (partly) rebuilding a Stax SRM1-MK2. Replaced all resistors, elco's and other caps. When done I hooked up the amp to do a test run (I dont have a Stax earspeaker to test) and sort Bias offset and balance out.

Firstly I just let it warm up. After an hour I noticed i forgot to turn the pots halfway to prevent too big of an offset/balance so the bigger resistors (the 27k 2W ones) for the left channel got a bit hot.

Turned off the amp, let it cool down and fired it up later while adjusting bias so to avoid this again. Let it warm up again, closed the lit and started adjusting the bias again. Finally I got all values for L and R channel close to zero V.

I'm just curious if I get the bias on offset and balance for left and right channel close to zero V; is this an indication the amp should work properly? I'm trying to get a hold on some cheap SR40's for example to really test it but I would like to know if I'm on the right track.

Any input would be appreciated

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