R60

[jdier]

I have a C84 that I built some time ago. It has worked flawlessly for me and performs well as a stereo pair with another C84.

I have one other C84 that is causing me trouble so I pulled my good ones so I could test some voltages on the good v. bad.

this question relates to one of the good ones.

in going through my testing I noticed that R60 was blown. I replaced it with a new resistor, balanced the voltages (which were still just about dead on) and it is again working perfectly as part of a stereo pair.

What would cause the R60 to blow, and how is it that the preamp appeared to be working well with it blown?

[DPLight]

was R60 open? Looking at the schematic R60 drives the - output and provides some feedback to the + output circuit. Could be that you had no - output and the lack of feedback caused the + output to make up for it.