6sn7, 6j5, 76's?

ALL212 · 4993

0 Members and 1 Guest are viewing this topic.

Offline ALL212

  • Sr. Member
  • ****
    • Posts: 542
on: February 27, 2019, 03:25:53 PM
When I built the BAC I wired and socketed it for 6SN7 in the 12au7 spot.  With the upcoming Crack sale I'm considering wiring this one for a pair of 6J5's for fun.  The old 76's look kinda ok...

Are a pair of 6J5's ok in the 12AU7 position (rewired and resocketed)?

Are a pair of 76's there ok - can the rest of the circuit handle this?  Much more research into availability to yet be done.  A friend was giving me "idea's".  I understand I'll need to source some 5 pin sockets.

Aaron Luebke


Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19766
Reply #1 on: February 27, 2019, 03:58:43 PM
The 6J5 should be about dead nuts on.

The 76 may need to have a little more plate current run through it.  Try an R1 around 213 ohms on the small board (215 should be fine/available).

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man



Offline ALL212

  • Sr. Member
  • ****
    • Posts: 542
Reply #3 on: February 27, 2019, 04:12:38 PM
I've got the first two adapters!

I turned a Schiit Saga into a two holer with the 6SN7 to 6J5 adapter and had folks at Odyssey Audio sweating (or was it I that was sweating) when I used 6SN7's in the 12au7 sockets on a Candela - no smoke from either.

Might be time to source some 76's...  8)

Aaron Luebke


Offline ALL212

  • Sr. Member
  • ****
    • Posts: 542
Reply #4 on: February 27, 2019, 04:40:14 PM
Let the giggling commence!

Aaron Luebke


Offline Paul Joppa

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 5837
Reply #5 on: February 27, 2019, 04:41:10 PM
FWIW, 6P5GT is a 76 with octal pinout - one less layer of adapters!

Paul Joppa


Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19766
Reply #6 on: February 27, 2019, 07:30:31 PM
Now I'm going to be thinking of what adapter you could plug into the 5 pin socket.

You can also go from a 6J5 to a 6C4.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Tom-s

  • Sr. Member
  • ****
    • Posts: 500
Reply #7 on: February 27, 2019, 07:51:42 PM
Here's 6J5 in my Crack. I like the sound. https://ep1.pinkbike.org/p5pb16745694/p5pb16745694.jpg
Another option might be to run 7193 tubes for driver with GEC A2293 for output tubes.
Because more tubes are better  ;D



Offline Tom-s

  • Sr. Member
  • ****
    • Posts: 500
Reply #8 on: March 03, 2019, 09:00:14 AM
I'm always willing to try new tubes, just for fun! Read the mention by PB in other topics about the 76 and 37 later developing into 6sn7/12au7. So I've order a box of 76 and 37 tubes to try in my Crack.
Anyone tried these yet? I'm a bit worried about the operating points not being optimal with Crack.

I use ECC82 -> 6J5 and bought a 6J5-> 76/37 adapter.



Offline Natural Sound

  • Sr. Member
  • ****
    • Posts: 998
Reply #9 on: March 04, 2019, 04:59:22 PM
This was a fun thread to read. Like the OP I installed a second octal socket and use a 6SN7. I've rolled quite a few of the alternatives with adapters and such into my first generation Crack amp. I always return to the 6SN7 for synergy. Specifically a Sylvania T-Plate "chrome dome" voltage amplifier with a Sylvania JAN triple mica 6080 power tube. As they say your mileage may vary but this seems to be my destination. At least until I can scrape up enough dough for a mainline. ;)



Offline ALL212

  • Sr. Member
  • ****
    • Posts: 542
Reply #10 on: March 06, 2019, 05:48:58 AM
Let's say that I'd like to go a bit crazy on this one.

76's, maybe 37's in the pre circuit.  6J5's for sure if stock on those looks low from suppliers.

How about those 7193's in the pre (not power) side?  I think it would look pretty cool with those Dr. Who dalek's running around.

I'm having a new plate cut anyway and it will be landscape oriented instead of portrait.  I've still got to check room for all of this but I think it might work.  Plate size will be about 10 1/4 x 8 1/2.

The odd plate size comes from a miscommunication between myself and the woodcutter for a prior base and then an additional issue with basic math.

Base.pdf would be "normal" just oriented differently
Base1.pdf could be a new dual tube layout.  Still much thinking needed on that one!
« Last Edit: March 06, 2019, 06:04:42 AM by ALL212 »

Aaron Luebke


Offline Tom-s

  • Sr. Member
  • ****
    • Posts: 500
Reply #11 on: March 06, 2019, 06:09:16 AM
Really nice! Looking forward to your new Crack!
The only tube i know of that might work as dual output is the GEC A2293.
Can't think of another that might work in the output of the Crack.



Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19766
Reply #12 on: March 06, 2019, 07:16:55 AM
Why four socket holes in the base?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline ALL212

  • Sr. Member
  • ****
    • Posts: 542
Reply #13 on: March 06, 2019, 07:21:26 AM
The four holes would be a misguided dream that I could split the 6080 somehow...

Unless there's a miracle it's going to be a three holer at best.

Base3.pdf is probably fairly realistic
« Last Edit: March 06, 2019, 07:29:01 AM by ALL212 »

Aaron Luebke


Offline Paul Joppa

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 5837
Reply #14 on: March 06, 2019, 08:18:57 AM
The 7233 is roughly half of a 6080.

Paul Joppa