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Author Topic: 12ax7,12at7,on Crack?  (Read 2097 times)

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Offline mikek200

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12ax7,12at7,on Crack?
« on: April 09, 2013, 10:57:16 AM »
Have the Crack with speedball.
Can the above 2 tubes ,be used on it

Thanks
M.

Offline Paul Joppa

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Re: 12ax7,12at7,on Crack?
« Reply #1 on: April 09, 2013, 01:25:07 PM »
No. In order to get the plate voltage low enough, they would have to be run in the grid current region, where distortion is increased.
Paul Joppa

Offline Paul Birkeland

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Re: 12ax7,12at7,on Crack?
« Reply #2 on: April 09, 2013, 05:08:27 PM »
In actuality, the first Crack that Doc B. and I built ran the 12AT7, but it had way, way too much gain for any headphones that we tried.  The 12AX7 will be much worse.

A 5687, 12BH7, 6CG7, or 12AU7 are the families of tubes that run well in this arrangement, with the 6CG7 having a different heater arrangement and the 5687 having an unusual and very different pinout.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline mikek200

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Re: 12ax7,12at7,on Crack?
« Reply #3 on: April 10, 2013, 05:13:11 AM »
OK,
Thanks guys