Einstein tube mixing/bias questions

[moltenmetalburn]

I ordered two sed 6550 to mix with the el34L that came installed in my Einstein. I am really loving the sounds im getting so I wanted to switch over gradually.

I have read the biasing information on the site but still have some additional questions. I want to assume nothing so I dont make any mistakes.

when looking at the amp from behind:

does the left red bias jack correspond to the left fuse?

which tube pair is read by that left most jack?

is it the two leftmost tubes or is it an outer and inner pair setup?

for the tube bias:

el34L at 70 ma?

6550 at 80ma or 100ma?

thanks i just want to get it right!

 

[duesentrieb]

Looking at the back of your amp you have on top the three slots for the probes (2 red - for the outer and inner pair) and ground - and the two trimmers (outer, inner). They are corresponding with the fuses on the back labelled outer and inner.

Look at the tubes from the back
1 - 2 - 3 - 4

2 and 3 are the inner tubes
1 and 4 are the outer tubes

so you could make a configuration like 6550 - EL34 - EL34 - 6550

bias the EL34s to 30-35mA per tube and the 6550 to 40-50mA per tube (60-70mA & 80-100mA/pairs)

in the pic the inner pair is biased.

 

[moltenmetalburn]

Thank you so much Olaf!