Bussy repairing a Studio Bass for a friend. There are 2 POT's at the rear: HUM adjust and TUBE balance adjust.
What is the correct procedure for setting this up?
Thanx for any assistance.
What is the correct procedure for setting this up?
Thanx for any assistance.
You may want to convert the bias adjustment from a balance type. This adjustment merely divides the bias evenly between the tubes instead of accurately setting the idle current.
blacklight said:
Thanx for the link. I also fond this one, very good quality, still need to know how to adjust these POT's for best results.
An externally hosted image should be here but it was not working when we last tested it.
I'm sure you'll find the answer in this link:
http://www.fenderforum.com/forum.html?db=&topic_number=410860&lastpost=2004-04-2619:15:57&offset=0
/Hugo
http://www.fenderforum.com/forum.html?db=&topic_number=410860&lastpost=2004-04-2619:15:57&offset=0
/Hugo
With a shorting on the input... or no input at all; connect a voltmeter from plate to plate (pin 3) on the output tubes. With the amp warmed up well, adjust the matching pot for zero volts. This matches the idle current (basically) through the tubes.
If the tubes are new, you may want to do this again after tubes have some hours on them.
With that done... simply adjust the hum balance for minimum audible hum at the speaker.
If the tubes are new, you may want to do this again after tubes have some hours on them.
With that done... simply adjust the hum balance for minimum audible hum at the speaker.
- Status
- Not open for further replies.