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Old 10th Nov 2019, 1:11 pm   #64
Join Date: Nov 2016
Location: Budapest, Hungary
Posts: 348
Default Re: Vintage Radio and Phonograph cutter schematic

Originally Posted by ms660 View Post
No hum with the volume control turned down and massive hum with volume turned up suggests 50Hz hum, sometimes caused by a screened lead that has lost it's ground connection or a control grid that's floating, ie: no or extremely high resistance to ground, other causes could be heater/cathode leakage in a valve.

Hum problems can be difficult to diagnose via the internet.....Is the hum level the same on Radio and Pickup?

Thanks Lawrence. I just googled a 100Hz hum and compared it and it is the same by the sound. Now I disconnected the two electrolytic 8A and 8B. Will order two new can ones.

Until that will arrive can not do anything further sadly. I thank you so much for your help Lawrence. I am learning so much from you here seriously, I owe you one.

Have a great weekend and will post here again when the cap's are her.

Ordering from hificollective UK proper filter cap's.

and forgot to answer your question, hum level is the same except the external speaker position on the switch.

Last edited by Levente; 10th Nov 2019 at 1:18 pm.
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