testingthevalves
Ex Member
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Hi, I'm a valve first timer who's trying to get the most out of this beautiful kit.
I bought two of them (2* zkit 4 each with it's zkit 5 power supply) and I have the same problem: everything works, but hum is beyond what I'd think acceptable. I know I'm doing something wrong. Thank you for pointing me in the right direction.
If I am not using a pot and directly wiring it to any solid state amp I've tried, I get a loud buzz. I NEED to attenuate the output to be able to make use of the preamp. Too bad.
One of the kits is in a grounded case. The other one, is sitting on my bench. No difference. Both hum too much.
As a valve, I am using the Electro-Harmonix 12au7 I had to buy some sockets as I have found two seven pin valve sockets in each kit inappopriately - not a big issue btw.
I've wired the power supply in air, followign carefully the schematics, with a couple of 20cm wires going to pins 2 and 5 of the rectifyer tube, which looks like starting up after 10 seconds of power.
I am using 220 and the primary mains series wired. Voltage output from the power supply looks correct.
All voltage wires sit away from signal path. Should I post some photos? Is there something I should check beyond voltages and evident shorts?
Thank you so much
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