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previous: wayne theanks billkilled the hum,... -- 3/20/2003 4:23 AM	View Thread

Re: A tidbit till the real amphounds show up..

3/25/2003 1:45 AM
Matthew Springer	Re: A tidbit till the real amphounds show up.. It sounds like the hum is almost certainly in the very early stages of the amp. Did you shield the input from the jack to the first gain stages grid? Definately shield the first stage. Next thing is to make sure the preamp is sufficiently decoupled from the rest of the amp. Try increasing the amount of capacitance on the firts stage and see if the hum goes down. Also try switching tubes around. Sometimes, you just get a bad tube. Also, try putting the two 100ohm resistors back in and lifting the heater ground center tap. -Matthew

3/25/2003 1:45 AM

Matthew Springer
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Re: A tidbit till the real amphounds show up..

It sounds like the hum is almost certainly in the very early stages of the amp. Did you shield the input from the jack to the first gain stages grid? Definately shield the first stage. Next thing is to make sure the preamp is sufficiently decoupled from the rest of the amp. Try increasing the amount of capacitance on the firts stage and see if the hum goes down. Also try switching tubes around. Sometimes, you just get a bad tube.

Also, try putting the two 100ohm resistors back in and lifting the heater ground center tap.

-Matthew

Replies:

mikey MatthewI am going to try th... -- 3/25/2003 10:13 AM