12AU7s

guitar007 · Post by **guitar007** » Mon Dec 05, 2005 5:18 pm

'Any of you guys use 12AU7s? I was digging through my tubes the other day and found a few.

clarkydaz · Post by **clarkydaz** » Fri Dec 09, 2005 5:18 am

they are a very low gain tube. great if you need the super clean sound. wont do the 'marshall' thing though

guitar007 · Post by **guitar007** » Tue Dec 13, 2005 10:10 am

Are they lower gain then a 12AT7?

Billy Batz · Post by **Billy Batz** » Tue Dec 13, 2005 10:17 am

Flames1950 · Post by **Flames1950** » Tue Dec 13, 2005 4:14 pm

guitar007 wrote:Are they lower gain then a 12AT7?

WAY lower........I don't know what you would want these for in the average guitar amp. But if someone really likes them I've got a Telefunken 12AU7 they can weasel outta me cheap.

novosibir · Post by **novosibir** » Tue Dec 13, 2005 4:37 pm

The µ (~ Gain) of preamp tubes:

12AX7: µ = 100
12AT7: µ = 70
12AY7: µ = 50
12AU7: µ = 20

But - the lower the µ of a preamp tube, the flatter its frequency response, what means in other words, that they'd have an extended low and high response in respect to the tubes with a higher µ.

Larry G

guitar007 · Post by **guitar007** » Wed Dec 14, 2005 12:07 pm

Brilliant! Thanks for the stats novosibir.

Where does the 5751 fit in gain wise?

novosibir · Post by **novosibir** » Wed Dec 14, 2005 1:15 pm

In my former post that have been about values out of my head - and anyway they're varying from label to label and from batch to batch.
But here again the µ of tubes EXACTLY, including the 5751:

The µ (~ Gain) of preamp tubes:

12AX7: µ = 100
5751: µ = 70
12AT7: µ = 60
12AY7: µ = 44
12AU7: µ = 17

Larry G

guitar007 · Post by **guitar007** » Thu Dec 15, 2005 10:01 am

Thanks again.