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Old 9th Nov 2019, 3:20 pm   #54
Levente
Hexode
 
Join Date: Nov 2016
Location: Budapest, Hungary
Posts: 348
Default Re: Vintage Radio and Phonograph cutter schematic

Quote:
Originally Posted by ms660 View Post
Is it the loud hum there when the volume controls are turned to minimum ?

Lawrence.
Both... popping sound and hum is there when the volume control is down, but when I start to turn up the hum gets even higher and louder and then a massive squealing starts...

I have several 6v6s and tried a few, all are having the same effect


I do not have another 6SC7 I am unsure on that

the 6SJ7s i have one extra so started swap them one by one, no change and I have none of the rest of the 6SA or 6SF tubes..

I was reading the robribinette site for trouble shooting but with these sounds, and those repeating popping (is that the osculation?) and squealing can be anything...

I am also really suspicious of the on/off switch pot.. the pot responds weirdly...

thinking of where should I start...

cleaning the tube sockets
check again the soldering? poking around with a chopstick?
ground connections... on the chassis counted 5 ground points in total
getting better filter caps?


Thanks Lawrence
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