So the R35 and R36 cannot be used to adjust the bias. Remember that the DC current going through the grid is very small so there will be only a small voltage drop across those resistors, if you want to adjust the bias you need to put something similar in place for R49.
So, you've boosted the values of the reservoir cap up to an effective 75uf. using two 150uf capacitors in series. I can see that now. I didn't see all of those caps you have over on the side of the amp by the power transformer.
its hard to say why your fuse is blowing, are you certain that the grids are seeing the bias voltage? double check power tube socket wiring. does the fuse pop right away? or does the amp warm up a little and then the fuse pops?
-Edit-
I should change my wording from R35 and R36 cannot be use, to should not be used simply to adjust the bias. it would be more effective to use the pot+resistor combo in place of R49. This way gives you a better sweep, and the load impedance for the phase inverter doesn't change with the setting of the bias.
So, you've boosted the values of the reservoir cap up to an effective 75uf. using two 150uf capacitors in series. I can see that now. I didn't see all of those caps you have over on the side of the amp by the power transformer.
its hard to say why your fuse is blowing, are you certain that the grids are seeing the bias voltage? double check power tube socket wiring. does the fuse pop right away? or does the amp warm up a little and then the fuse pops?
-Edit-
I should change my wording from R35 and R36 cannot be use, to should not be used simply to adjust the bias. it would be more effective to use the pot+resistor combo in place of R49. This way gives you a better sweep, and the load impedance for the phase inverter doesn't change with the setting of the bias.