Hiwatt DR504 adjustable bias?

[Trotter]

Does anyone know if a stock Hiwatt DR504 has an adjustable bias or not?

I've read some 504's do, but I'm not sure if this was a mod or not.

I'm getting ready to re-tube my early 80's 504.

Thanks!
Paul

[RedMan]

They don't but it's an easy mod to do. I did it on mine.