News: Trouble logging in? Log in from the login page.
December 06, 2019, 10:42:37 AM

Author Topic: 12AU7 Tube in Shunt Regulator  (Read 251 times)

0 Members and 1 Guest are viewing this topic.

Offline grufti

  • Full Member
  • ***
  • Posts: 244
12AU7 Tube in Shunt Regulator
« on: August 09, 2019, 01:11:56 PM »
What prompted the change to the 12AU7 in the Eros 2 shunt regulator? Can I still use the 12BH7 that used to occupy that spot in the original Eros Phono? The shunt circuit has now gone from 6CG7 to 12BH7 to 12AU7 over the life of the circuit. They're all similar, but the plate dissipation limit is definitely lower for the 12AU7.

Online Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 11719
Re: 12AU7 Tube in Shunt Regulator
« Reply #1 on: August 09, 2019, 04:40:07 PM »
The dissipation is lower for the 12AU7, but still well above what we need.  The 12BH7 was only being used in the Eros, so we switched over to the 12AU7.  The 6CG7 was drawn in a really early schematic, but never actually provided with the kit (I did build one a long time ago with a 6CG7 just for fun though).
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline grufti

  • Full Member
  • ***
  • Posts: 244
Re: 12AU7 Tube in Shunt Regulator
« Reply #2 on: August 12, 2019, 11:37:26 AM »
I still have some "new" old 12BH7 tubes sitting around. I'll use one of those unless you tell me that it's a bad idea. Everything else being equal the 12BH7 should last longer in that position than a 12AU7. Is there anything else that I should consider? Amplification factor is the same at 17. The transformer should be able to handle the heater current. Am I forgetting something? Does the 12UA7 shunt regulator sound better? You never know until you've tried. Do you have a preference?

Online Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 11719
Re: 12AU7 Tube in Shunt Regulator
« Reply #3 on: August 12, 2019, 01:51:33 PM »
You are welcome to experiment to your heart's content.  The 12BH7 for us ended up being a redundant component that we had to stock.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man