I ended up not being able to buy the amp. The seller passed those two videos and gone kaput.

Saw another post from another forum with the same issue. People are saying that it is just a normal hum/buzz for the loud 1959rr:

http://www.marshallforum.com/showthread.php?t=42496

Mine was with those resistors replaced. The amp tech told me not to use the bias function a lot. :)

the bias are as follows:

tube 1 = 35.7mA
tube 2 = 37.7mA
tube 3 = 39.5mA
tube 4 = 41mA

Thanks for the reply. The tubes have been there for a long time but I barely used this amp. the amp is 8 years old but playing time is very low.. but I guess the tubes can break anytime. I tried the same thing with my self biasing AFD100: placed the bias probes on one power tube then checked the bia...

Yes, with or without the guitar plugged in it is the same. Last night I was able to manage to remove some hum by biasing it and moving the potentiometer for the hum. Now, i am not sure if this is normal: I did not remove the biasing meter and played a bit... then i notice when i put the volume highe...

Hi

I have the same problem as this:

https://www.youtube.com/watch?v=_gd85juTGeU

I pulled the PI and the hum disappeared. I tried 8 different preamp tubes but to no avail...

Any ideas guys?

Thanks

Here are the videos:

buzzing only on zero volume

https://www.youtube.com/watch?v=fsg4QraSCpw&feature=youtu.be

and

https://www.youtube.com/watch?v=E7lmgB6QOX8&feature=youtu.be

What seems to be the problem? Thanks!!!

Hi Guys,

Wanted to ask what is wrong with the amp if the volume is zero but there is a loud buzzing sound. If the volume is applied let say from 1 to 10 the buzzing sound is not heard.

Thanks for the replies.

Cheers,
Oliver