Retubing a 5150...

[Impervious]

Does it have a cathode bias? Or will I have to manually adjust it?

I don't particularly know much about this... But, I know how to bias an amp, I just don't really know when it's needed and what not. haha.

Thanks...

 

[elmuchoescadawg]

The 5150 is self biasing and the mk2 isnt from what I remember

 

[JeffTD]

MK1 (5150 as opposed to 5150II) is actually fixed, not self biasing. You can't change the bias without mod'ing the amp.

On the 5150II, there's a small knob next to the powertubes that adjusts the bias within a small range, but it really isn't enough to screw anything up.