Posts: 13
Threads: 6
Joined: Aug 2024
City: Satsuma
State, Province, Country: Florida
Drowning in a overloud buzz/Humm. Have already changed filter caps,bakelite blocks( caps),out of speck resistors,checked many grounds. Changed & tested tubes,usual voltage checks, removing 6j7's an still have buzz/humm.Running short on ideas!
Thank everyone for any direction resolving
Bruce
Finally after 50 plus years I'm back into the hobby again. It's like trying to relearn a second language some of it makes sense and some of it doesn't! Could be fun now considering my son is now into old radios and tube technology!
Posts: 1,720
Threads: 110
Joined: May 2008
City: Omak
State, Province, Country: WA
Hello Bruce,
First all do mean a 37-84b ?
Did you take any before and after pictures ?
is it a buzz like when you touch input to amp or is it a hum ?
Sincerely Richard
Posts: 4,808
Threads: 54
Joined: Sep 2008
City: Sandwick, BC, CA
I would have to look at the schematic but it's not uncommon in 1930s AC radios to have the negative of one filter cap connected to the center tap of the high voltage winding, and the other to chassis, with a series of wire wound resistors in-between. It's a common mistake a lot of people make because they are used to working on 1940s and 50s radios that have the tubes cathode biased rather then fixed bias, so in effect one filter cap is open circuit if you connect both to the chassis.
Regards
Arran
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