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previous: Bruce Yes. If you have room, install a 1%... -- 3/15/1999 9:09 PM

Re: Newbie: hum problem

3/16/1999 10:47 AM
Giacomo	Re: Newbie: hum problem Bruce, yesterday has been a very bad day for me. First I had a little incident and now I cannot walk because of a knee trouble. Second, my wife was attempting to reorder my toy room and the amp chassis dropped on earth breaking one 6L6 (I think that Freud should have some good explainations for this ). I have to arrange with the few things I have at home. I measured idle current with my analog VOM and a 5 Ohm 5% resistor . I read the following values (not divided by 5) using only one socket and alternating the tubes (wrong?): 1- 30 mv 2- 40 mv 3- 50 mv 4- 0 mv 5- 25 mv 6- 20 mv I think there's something wrong in the measurement but it could give an idea of the RELATIVE values. Then I measured the voltage across screen resistors: 1- 35 mv 2- 40 mv 3- 50 mv 4- 0 mv ( I argue it's dead) 5- (broken) 6- 30 mv I tried driving the amp with only tube 1 & 6 (one per side). The hum almost goes away. Could I assume that hum prob is only in tubes mismatch? Thank you for your attention. Giacomo

3/16/1999 10:47 AM

Giacomo

Re: Newbie: hum problem

Bruce,

yesterday has been a very bad day for me. First I had a little incident and now I cannot walk because of a knee trouble. Second, my wife was attempting to reorder my toy room and the amp chassis dropped on earth breaking one 6L6 (I think that Freud should have some good explainations for this ).
I have to arrange with the few things I have at home. I measured idle current with my analog VOM and a 5 Ohm 5% resistor . I read the following values (not divided by 5) using only one socket and alternating the tubes (wrong?):
1- 30 mv
2- 40 mv
3- 50 mv
4- 0 mv
5- 25 mv
6- 20 mv
I think there's something wrong in the measurement but it could give an idea of the RELATIVE values. Then I measured the voltage across screen resistors:
1- 35 mv
2- 40 mv
3- 50 mv
4- 0 mv ( I argue it's dead)
5- (broken)
6- 30 mv

I tried driving the amp with only tube 1 & 6 (one per side). The hum almost goes away.
Could I assume that hum prob is only in tubes mismatch?

Thank you for your attention.

Giacomo