sunn reverb

[daddyo]

my 1969 solarus reverb works, but when I go between two and three the amp starts getting muddy and starts humming alot. i've got the original pan, with the spring stop. I put another pan in it, and it stills does the samething. it's a 6550 amp, and has all new tubes. whatta think

[elektron]

I can share my experiences fixing reverb on 190L which is similar.  My amp was quite until I turned up the reverb then loud hum very weak reverb.  I replaced the electrolytic caps in that circuit and that help with most hum but the reverb was still weak.  I replaced the corroded connectors that helped with most remaining hum but still weak.  I finally replaced the RT3 transformer and that solved the problem.  Hope this helps.

[daddyo]

thanks, i'll try changeing the caps and the transformer, thats the small one on the top right

[daddyo]

could you tell me the size of ths caps you used for the reverb.

[elektron]

I sent you a PM but I replaced all the caps on vibrato and reverb circuits both electrolytics and others.  Caps are cheap relatively and if your going to go thru the trouble I figure might as well change em all because you can't always tell if a cap is bad just by looking and removing them from the circuit to test is the same amount of work as putting in a new one... anyway my philosophy for what its worth.  I got the transformer from Triode Electronics... In my case I think most of my problem was corroded connectors.. I cleaned them with contact cleaner but that seem to do nothing then I replaced the connectors and made sure they made a good chassis ground connection.....