Parts layout is very important in any amplifier design! Keeping the power supply/transformer away from the input stage, wire length and routing ... Grounding issues? Did you use star grounding (tieing all grounds to a single point on the chassis)? Tieing all power supply grounds together and connecting them to the chassis near the transformer is one solution. So is using a bus bar running the length of the chassis and connected at one end as a common ground is another method.
Please help! Tube amp issue
I am extremely new to building tube amplifiers. I've never done this
before, but this concept intrigued me alot, therefore I decided to build
one. I followed a schematic of a 20W pc tube amplifer. To my knowledge,
and to checking my work multiple times, I have followed the schematic
religiously. I think it's from an old Magnavox amplifier.
When the amp switches on, there is an insane amount of noise, even when there is no audio input given. The only modification I have made is that I have changed is the main power tranformer's primary voltage due to where I live. (120x2)
I'm not allowed to post the schematic's diagram, but I may link the page:
http://www.wkinsler.com/radios/7tubeamp1.html
If anyone could please dissect the schematic to see if there could be a potential problem with the design itself, that would be fantastic.
I have also takena a video of my amp groaning the noise away to glory: (One of the pre amps do not work, but then i disconnected one side of the amp, and the noise still existed)
https://www.youtube.com/watch?v=Myj-aIommmA
When the amp switches on, there is an insane amount of noise, even when there is no audio input given. The only modification I have made is that I have changed is the main power tranformer's primary voltage due to where I live. (120x2)
I'm not allowed to post the schematic's diagram, but I may link the page:
http://www.wkinsler.com/radios/7tubeamp1.html
If anyone could please dissect the schematic to see if there could be a potential problem with the design itself, that would be fantastic.
I have also takena a video of my amp groaning the noise away to glory: (One of the pre amps do not work, but then i disconnected one side of the amp, and the noise still existed)
https://www.youtube.com/watch?v=Myj-aIommmA