I have an Origin 20 Combo and I just bought a new set of tubes, and I was wondering if i have to take it to a technician to bias it, or even if it needs to be biased?

THANKS

Hi - 

  I wanted to change the power tube in my DSL1HR Head.  Will it need Re Biasing ? or I can go ahead and just swap the tube and no problems it is good to go. 

Thank You

Can anyone tell me the correct bias settings for a Marshall TSL602? There is conflicting info out there.

Tthe TSL range have 3 pins under an inspection cover on the back. Some people say that the bias should be set to 40mv between the middle pin and the outer (total 80mv). Others say that it should be 80mv per side.

I’ve had the amp for 18 years and always have it set just short of 80mv, but I never seem to get much life out of my valves – probably half the 1,000 hours you’d expect. And the sound always seems to lack a bit of treble. Whenever I have it serviced, it always seems to come back set at around 80mv per side but it always seems to run a bit hot to me.

 Should I be lowering the bias?

I recently bought a new DSL40CR. Great sounding amp! Great tones! I am noticing that the low end sounds a bit flubby. I was reading in some forums that this can be caused by improperly adjusted BIAS. Can anyone direct me as to what the mV for each left and right tubes should be set to?

I have a DSL1CR when replacing pre and power valves does the amplifier need biasing, is it self adjusting? And what would be good replacement valves?