VSi60 Bias Adjustment


Today I checked the bias settings on my VSi60 and I get a 0 millivolt reading from one of the tubes.   The amp was warmed up for 30 minutes before the test but was not connected to my speakers while testing.  The other 3 tubes show a 60mv reading.

To try to see if it was a bad tube I did try another tube set (KT-120) in the amplifier and I got the same result.   So it's probably not a bad tube.

I'm fairly new to tube amplifiers but I have had the VSi60 for a couple of years and I do like it.

My question is what do I do?   I cannot fit the plastic screwdriver that came with the amp into the slot of the bias adjustment of the tube that needs adjusting.   Should I unscrew the trim plate on top and make a bias adjustment?   Or is the amp broken and in need of service?    The amp sounds fine but I would like to know what's going on.





johndyson

Showing 1 response by imhififan

Today I checked the bias settings on my VSi60 and I get a 0 millivolt reading from one of the tubes.   The amp was warmed up for 30 minutes before the test but was not connected to my speakers while testing. The other 3 tubes show a 60mv reading
I think the speakers should be connected to the amp outputs.