Hi,
After some research, I found this answer from one of the previous posting.
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If you are driving the amp single ended, the V-1 tube IS in the signal path in order to convert the incoming un-balanced signal to a balanced signal to drive the rest of the amp. Each side of this double-triode tube handles one channel. So it's CRITICAL that both sides of this tube (regardless what brand) have matching Gm (which stands for transconductance or gain) otherwise your channels could be unbalanced; and since they dropped the gain controls on the model V (Infinity-Audio,) you can't be fixing an out-of-balance tube at the amp anymore. V-2 and V-5 should be reasonably matched (within 20%) both internally and with each other. Ditto the pairs V-3,4 and V-6,7.
If you eventually acquire a preamp with balanced outputs and can drive the amp balanced (highly recommended) you will still need to keep some 'ole 12AX7 in the V-1 position to complete the filament circuit, but it won't be doing anything with the signal, so it need not be something expensive -- even one of the OEM 12AX7's will do ;-)
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Anybody have any opinion?
Thanks.
After some research, I found this answer from one of the previous posting.
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
If you are driving the amp single ended, the V-1 tube IS in the signal path in order to convert the incoming un-balanced signal to a balanced signal to drive the rest of the amp. Each side of this double-triode tube handles one channel. So it's CRITICAL that both sides of this tube (regardless what brand) have matching Gm (which stands for transconductance or gain) otherwise your channels could be unbalanced; and since they dropped the gain controls on the model V (Infinity-Audio,) you can't be fixing an out-of-balance tube at the amp anymore. V-2 and V-5 should be reasonably matched (within 20%) both internally and with each other. Ditto the pairs V-3,4 and V-6,7.
If you eventually acquire a preamp with balanced outputs and can drive the amp balanced (highly recommended) you will still need to keep some 'ole 12AX7 in the V-1 position to complete the filament circuit, but it won't be doing anything with the signal, so it need not be something expensive -- even one of the OEM 12AX7's will do ;-)
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Anybody have any opinion?
Thanks.