In my amp design I have separated everything past the PI : dual
bias supplies, cathode resistors and caps, etc. This is mostly to
make it easy for me to go from single-ended to push-pull (AB). Up
until now I've thought that to go from one configuration to another
would require changing the output transformer but now I'm wondering
if I couldn't use a push-pull OT for both, and only use half of the
OT for single-ended use.
Is this possible ? The OT I plan to use for push-pull (Allen TO25)
is 7000 to 4/8 ohms and the OT for single-ended (Allen TO11C) is
4000 to 8/16 ohms. Would using only one half of the push-pull still
give 4/8 ohms at the secondary ?
Or could I use two SE transformers and somehow combine their
secondaries ?
I suppose I could mount both a SE and a PP OT and switch from one
to the other but this would mean switching high voltages (?).
Victoria Amps produce an amp that does this sort of thing but it apparently
uses a special OT :
"The Regal II is designed around a custom bifilar output transformer
that is essentially two discrete transformers driving a common
speaker load."
(see http://www.victoriaamp.com/visitor/show_model/14)
Paul P
bias supplies, cathode resistors and caps, etc. This is mostly to
make it easy for me to go from single-ended to push-pull (AB). Up
until now I've thought that to go from one configuration to another
would require changing the output transformer but now I'm wondering
if I couldn't use a push-pull OT for both, and only use half of the
OT for single-ended use.
Is this possible ? The OT I plan to use for push-pull (Allen TO25)
is 7000 to 4/8 ohms and the OT for single-ended (Allen TO11C) is
4000 to 8/16 ohms. Would using only one half of the push-pull still
give 4/8 ohms at the secondary ?
Or could I use two SE transformers and somehow combine their
secondaries ?
I suppose I could mount both a SE and a PP OT and switch from one
to the other but this would mean switching high voltages (?).
Victoria Amps produce an amp that does this sort of thing but it apparently
uses a special OT :
"The Regal II is designed around a custom bifilar output transformer
that is essentially two discrete transformers driving a common
speaker load."
(see http://www.victoriaamp.com/visitor/show_model/14)
Paul P
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