12ax7,12at7,on Crack?

mikek200 · 3454

« previous next »
Pages: 1   Go Down

0 Members and 1 Guest are viewing this topic.

Offline mikek200

  • Jr. Member
  • **
    • Posts: 37
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

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 5833
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

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19750
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

  • Jr. Member
  • **
    • Posts: 37
Reply #3 on: April 10, 2013, 05:13:11 AM
OK,
Thanks guys


Pages: 1   Go Up
« previous next »