|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
199.82.243.101
In Reply to: RE: Do your voltages somewhat match the schematic? (nt) posted by vinnie2 on June 21, 2017 at 13:42:38
Measure in sections: Get the power supply stable, then install and measure the the front-end/driver section, then plug in and measure the output tubes. It will help you nail down the problem.
Follow Ups:
Did like you suggested. PSU is ok, nice and steady by itself. Then I installed just the driver 12at7 tube and it's voltages are pretty much in the ballpark. I then plugged in the 6bq5's. I was getting around the 13 volts at the cathode resistor with the 400 ohm resistor in place that the schem calls for, for about 33 mA for cathode current if I am doing the calcs right. The tube manual says it should be about 65 mA, but would that be for a shared cathode resistor too? Still distorting a lot. The other voltages are in the ballpark too. I am at a loss as to what to try next. Maybe I should test some 6bq5's and !2at7's and make sure I have a good set of tubes? Maybe hook a test signal to it and follow it through on a scope and see if I can see where it starts distorting?
Edits: 06/22/17
I think the power supply is ok because it is one from another amp, but I will check it. I will try isolating the other sections in the morning. Thanks for the tip.
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: