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Preamp tubes
Posted: Sun 08/03/08 6:19 pm
by krisuk
Was just reading the thread Clean headroom and saw 5751 tubes being mentioned.
I have an 18W TMB and was wondering how these compare tone wise to a 12AX7?
Posted: Sun 08/03/08 8:10 pm
by joe6v6
5751 has a gain factor of 70 while a 12ax7 has a voltage gain of 100, tonewise they are similar but some people like to use them in place of a 12ax7 to lower the overall gain slightly and they will sometimes help quiet down an otherwise noisey amp. . . JOE
Posted: Sun 08/03/08 9:16 pm
by Phil_S
Be aware that the actual gain in the circuit is not the same as the tube's rating.
Posted: Sun 08/03/08 11:01 pm
by Alexo
Never hurts to try 'em! They can usually be had cheaper than 12AX7's, they can sound a little smoother, or a little "bluesier," if that's a word.
Posted: Mon 08/04/08 6:10 pm
by I360UP
They were used a lot in old Fenders, great in V1. Oh, hell am I aloud to use the "F" word here.
BL
Posted: Mon 08/04/08 9:01 pm
by morcey2
I like 5751 and 12AY7 both for dropping gain. For blues night, I throw a 12AY7 into V1 on my Plexi6V6 and occasionally into the PI in my LiteIIb. It doesn't really give more clean headroom, just delays breakup a little.
Matt.