Left channel is not at the same level as the right channel ????

[audiblesoundwave]

Hi everyone,

Lately, my left channel on the FPIII is not as loud as the right channel!  I spent a couple of weeks on isolating the cause.  I swapped cables, different side of the amps (are mono amps), swapped tubes on the FPIII; finally, my conclusion is something may be not working properly on the left side of my FPIII.  The high seems to be cut off quite a bit.  I feel the volume is reduced 2-3 clicks, 3-6db (I am guessing)

I am planning to dust off my manual and start to check out the resistance and voltage of the soldering points this coming weekend.  However, I decided to check with the forum to see any advises where to start first on finding the problem.

Any inputs?

Thanks,
Milton

 

[JC]

To be perfectly honest, it sounds as if you are already headed down the path I would take.  If the various swappings you have tried resulted in the issue staying on the same channel, then comparing the resistance and Voltage measurements between the two channels and against the manual seems like exactly the right "next step".

Going over the signal path from input to output on the side with issues, looking for suspicious solder joints, might also be of use; I always recommend a good light and a magnifier, since my eyes are getting older!  In my experience, a flaky solder joint can easily account for 3dB.

Good luck with your hunt!