[jaycalgary]

I have been struggling to get a good balance between left and right channel for some time now. I even re-soldered and swapped the left right channels in my Lambda sigs. The problem stayed now it is just
in the swapped driver. I notice if I unplug the earphones and plug them back in they seem to be balanced for a short while. There is a few white internal pots in the SRM-1/MK-2. Could these be part of the problem?
Should these pots be adjusted with a multimeter and is there any info on what would be correct? I am thinking of putting new caps and wire maybe resisters but can't find anywhere that this has been done yet.
I am in Canada and going to look at Parts Connexion to see if they have what I need. Any recomendations on good wire? Is it any better if the wire to the volume pot is rf insulated?

 

[spritzer]

Those pots are for adjusting the amp but the balance has nothing to do with how the channels interact with one another, it is to adjust the balance between the + and - halves of each channel.  Now if the offset on one channel is out of whack then you could have diminished output level or there is simply something broken in the amp. 
 
There should be two pots per channel, one marked balance and the other one marked offset.  To adjust them you need a multimeter set to DC volts and you insert the probes into the Stax socket.  To adjust the balance you put probes between the + and - outputs for that channel and adjust for 0VDC.  Now to adjust the offset remove the probe from the - output and connect it to ground (i.e. anywhere on the chassis, including the grounding post in the back) and adjust for 0VDC.  Now repeat for the other channel.  While you can do this with the amp cold it is best to do it when it is running at its regular operating temperature as heat is a factor here.  The Stax pinout can be found all over the place. 

 

[jaycalgary]

Thanks I now know how to make that adjustment. They probably do get corroded over time so readjusting them may have a benefit.

 

[spritzer]

It has nothing to do with corrosion but all componenets drift with time as they go through thermal cycles heating up and then cooling down.  Add that to the very simple unregulated PSU in all Stax amps and that the conditition of the capacitors has a large effect on its output.  Since even the newest SRM-1 Mk2 is about 20 years old I'd say they are all due for some minor surgery to have their electrolytic capacitors replaced. 

 

[jaycalgary]

well very simple to replace the caps the amp only has a few. Pretty impressive.