I'm making a guitar amp that uses a 6SN7 for the preamp and since my background is primarily with 12AX7's, I need some starter information about what values to use with the 6SN7.
Here is what I anticipate doing as far as topology goes.
6SN7 triode >> tone stack >> volume control >> 6SN7 triode >> 12AX7 phase inverter >> output tubes
What values should I expect for the 6SN7?
When using 12ax7's I traditionally have a 1M grid resistor before the preamp tube. Would 1M still work here?
When using 12ax7's I traditionally have a 1.5k Rk and 25uF Ck. Would that work here?
When using 12ax7's I traditionally have a 100k Ra. Would that work here?
I of course will tweak to taste, but I just need some starting information. Thanks for your patience with a newbie. 🙂
🙂
Here is what I anticipate doing as far as topology goes.
6SN7 triode >> tone stack >> volume control >> 6SN7 triode >> 12AX7 phase inverter >> output tubes
What values should I expect for the 6SN7?
When using 12ax7's I traditionally have a 1M grid resistor before the preamp tube. Would 1M still work here?
When using 12ax7's I traditionally have a 1.5k Rk and 25uF Ck. Would that work here?
When using 12ax7's I traditionally have a 100k Ra. Would that work here?
I of course will tweak to taste, but I just need some starting information. Thanks for your patience with a newbie. 🙂
🙂
1M grid resistor is well within the 6SN7s ratings.
The size of the plate and cathode resistors will depend on what you want to set as operating points for those stages and what the B+ supply is. If you can get an RCA Tube Manual (and they're available- I think that AudioXpress has reprinted the RC-30), there's a whole set of tables in the back with suggested circuit values for different B+ voltages, what gain you'll get, and how mnuch voltage you'll be able to swing. Very handy!
Understand that, compared to 12AX7, you'll get a lot less gain.
The size of the plate and cathode resistors will depend on what you want to set as operating points for those stages and what the B+ supply is. If you can get an RCA Tube Manual (and they're available- I think that AudioXpress has reprinted the RC-30), there's a whole set of tables in the back with suggested circuit values for different B+ voltages, what gain you'll get, and how mnuch voltage you'll be able to swing. Very handy!
Understand that, compared to 12AX7, you'll get a lot less gain.
And you can find those tables here (at the bottom): http://www.triodeel.com/tubedata.htm
Best regards,
Mikkel C. Simonsen
Best regards,
Mikkel C. Simonsen
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