Tweet
This amp just came across my bench with noise complaints. As the 3 factory main filters (3 X 30 mfd @ 500V) were still in place making them 20 years old I replaced them along with the 3 6800mfd @ 10V DC heater filters. I then formed these e caps in the amp and on the Variac overnight. This eliminated all objectionable hum but left a sputtering in the rhythm channel that sounded much like a parasitic issue. The pc board in this amp is very thin and had several "waves" in it from the substantial pressure exerted on it by the stout springs in the 4 tube cans. I removed them without creating more noise problems. They were returned to the customer with instructions to avoid their use! After a few days the board returned to a less wavy state. I then reflowed all of the joints around V1 & V2. This board remained VERY microphonic even after replacing all tubes. However all of this work DID bring the noise floor down to a very quiet level. I hope that this post might help someone else facing those mean ol' parasitic blues. Rich
-
-
Good information. Years late seeing this, but I thought those springs too tight the first time I changed tubes on my Rocket 4Forty and cut and bent the springs shorter. Sometimes I'm a rebel and just leave the cans off. Don't notice an difference when I do.
I'm also in Tulsa and may someday need a good tube amp repair guy (used to use David Hicks or Rick Potter, but both have sadly passed on). Is there a way to contact you if I do ?? -
You may try a P.M to him - he hasn't logged in here since March 2018Comment
Comment