6SL7/6SN7

for Dynaco Mark II/III/IV and DIY PP monoblocks

6SL7/6SN7

Postby bean_counter » Fri Apr 17, 2015 9:32 am

Hi,

Are any mods needed to swap in 6SL7 and 6SN7 for the 12AX7 and 12AU7 on the Poseidon board? (Other than octal sockets of course)

Thanks!
bean_counter
 
Posts: 4
Joined: Sat Aug 06, 2011 9:48 pm
Location: Near Chicago

Re: 6SL7/6SN7

Postby Geek » Fri Apr 17, 2015 11:22 am

6SL7 == 5751
and
6SN7 == 6CG7/6FQ7

A common error to mistake them for 12AX7 and 12AU7 respectively. They bias different and more importantly, they sound different ;)

Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3563
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia

Re: 6SL7/6SN7

Postby bean_counter » Fri Apr 17, 2015 11:44 am

Agreed... I normally don't swap them without circuit changes.

I have read comments on other forums that the octal are close enough in the Poseidon circuit and it was ok to simply swap. A straight swap just didn't jive with past experience; thus, the question.
bean_counter
 
Posts: 4
Joined: Sat Aug 06, 2011 9:48 pm
Location: Near Chicago

Re: 6SL7/6SN7

Postby Shannon Parks » Wed Jun 17, 2015 4:33 am

This would probably be A-OK, but two thoughts:
- I'd definitely re-tune the global feedback capacitor. Test with 10kHz square wave and adjust for minimum ringing.
- With the Poseidon and the 12AX7, only a single triode's heater is functioning as the circuit uses the center tap. This was done to increase life if "mirror swapping" and also to avoid possible extra noise. If noise is an issue, possibly tie the unused portions (k2, g2, & p2) of the 6SL7 triode to ground.

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3761
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington


Return to poseidon

Who is online

Users browsing this forum: No registered users and 1 guest

cron