Posted by Damir [ 213.202.96.185 ] on September 13, 2006 at 15:07:32:

In Reply to: Re: Steve Brown and I are working on this amp posted by bill epstein on September 13, 2006 at 06:08:25:

Direct coupling has a large advantages - omiting of the coupling cap and grid choke, driver "sees" very high impedance of the output tube grid as a load, etc. Less safe and large B+ are "drawbacks"...
I considered similar circuit ("classic" SE, not parafeed), 2A3 (AD1, etc.) direct-coupled with CCS-ed 6SN7 as a driver. With convential OP (250V/-45V/60mA) input sensitivity is about 1,5Vrms...but, B+ is about 550V.
Probably, sonic "plus" gained with omitting cap/grid choke combo is a large enough to accept high voltage...just a few thoughts.

Anyway, keep us posted about your progress, seems like a interesting amp/circuit. Is the driver paralleled ECC81?

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