Preamp tubes

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krisuk
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Preamp tubes

Post 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?
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joe6v6
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Post 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
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Phil_S
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Post by Phil_S »

Be aware that the actual gain in the circuit is not the same as the tube's rating.
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Alexo
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Post 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.
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I360UP
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Post by I360UP »

They were used a lot in old Fenders, great in V1. Oh, hell am I aloud to use the "F" word here. nono
BL
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morcey2
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Post 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.
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