hi all,
in a mu follower stage schematic with 6ag7 as 'top' tube and 6sl7 as 'bottom', or gain tube,
i see 230V on the 6ag7's cathode.
both tubes data say max +- cathode to heater voltage is 90v.
the only way i see to keep both in spec is with separate heater supplies with different reference voltages, or am i missing something?
(i think) it's supposed to run with one heater supply, but how much elevation would work?
thanx for your time
in a mu follower stage schematic with 6ag7 as 'top' tube and 6sl7 as 'bottom', or gain tube,
i see 230V on the 6ag7's cathode.
both tubes data say max +- cathode to heater voltage is 90v.
the only way i see to keep both in spec is with separate heater supplies with different reference voltages, or am i missing something?
(i think) it's supposed to run with one heater supply, but how much elevation would work?
thanx for your time
You are correct.
The second filement supply should be elevated to about 200V via a
divider between B+ and ground.
It's the input stage of laurel 300b amp, the schematic i got shows 410v on the 6ag7's anode,
230v on it's cathode,
180v on the 6sl7 anodes, and 2v on it's cathodes
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