|
Post by monza1x12 on Oct 20, 2011 7:09:14 GMT -7
with the brake lite off and nothing plugged into the monza........if i turn it up all the way the amp will start screaming/ feeding back.
also has a super loud hiss turned up
|
|
|
Post by pcns on Oct 20, 2011 8:24:08 GMT -7
I love this "if I turn it up all the way" lol AWESOME!!
Sorry, if its going microphonic could be a tube. Take a pencil with errasor on it and tap each tube with the volume up, of you get that make some noise when you bump it, replace it.
my bet is V2
|
|
|
Post by randalp3000 on Oct 20, 2011 11:15:21 GMT -7
yep take the covers off the preamp tubes and give them a little tap with your fingernail or a pencil and if it gives a loud pinging noise and starts to feedback that would be the culprit.
Might be easier to turn the amp up to just below where it starts to feedback.
I've been testing a lot of new tubes and about 3 out of 10 are micro phonic. I've had good luck with the new EH and Tungsol 12ax7's. I've had big problems with anything that has a long plate being micro phonic (jj's and sovtec 12ax7lps).
good luck and keep us posted rp
|
|
|
Post by Norrin Radd on Oct 20, 2011 13:10:57 GMT -7
I've had tremendous luck with EH tubes lately. Not so much on the JJs.
|
|
|
Post by pcns on Oct 20, 2011 16:05:14 GMT -7
^^^^^ Dr Z said was saying the say thing at Zfest this year
|
|