Posted by Chris O on October 05, 2000 at 12:10:39:

In Reply to: Re: V.35 amps posted by George on October 04, 2000 at 17:07:54:

George,
The most likely cause of hum in a newly constructed amp is the internal ground wiring. Carefully go back through the construction process and check to make sure that you followed the grounding suggestions and schematics to the letter. If this was done and the hum still persists, try moving some of the internal grounds to a central ground (star ground). Also, you did not mention if the hum was coming from one or both channels. If it was one channel, switch the interconnect leads coming in to the amp to see if the hum follows. This would indicate a system ground loop. You could try floating the associated equipment earth grounds on the a/c plug or on the amp itself. You could also try cutting the grounds on one end of a cheap pair of interconnects to see if it helps. Try switching the tubes around to see if the noise follows one tube in particular. Chances are that the hum is due to internal ground wiring inside the amp. My v35 is dead quiet. Good Luck. Chris O