Any 6SN7 Guitar amps?

[Cygnus X1]

I think mine is 6k but it is very close to being all the way to 0. With 340v on the tube, the bias is 9.4mv or about -11V. With a -13V supply, it doesn't take much to pull the supply voltage down.

Brian

So, which would you guess for running it single ended...a 1K?

[GainMaster]

I think mine is 6k but it is very close to being all the way to 0. With 340v on the tube, the bias is 9.4mv or about -11V. With a -13V supply, it doesn't take much to pull the supply voltage down.

Brian

So, which would you guess for running it single ended...a 1K?

If you parallel the output of the tube then half that or thereabouts. Stick a 1k in there then bias properly later. I had my RCA biased so hot it pulled my B+ down 40v and it didn't blow. A very rugged tube.

Brian

[dovii]

Hey, just going to add my two cents. There was a comment that 6sn7's are prone to be microphonic. A couple of years back I built a SE 300b stereo amp with 6SN7GTB's as the preamp driver tube. I replaced them with 5692 RCA Red Base tubes. These are an exact replacement but are miltary grade with I think 10,000 hr life. These are known through the Audiophile world as the "Cat's Ass" if you know what I mean. Not cheap but I found them to be worth every penny. There is another tube the 5691 which is the military grade version of the 6SL7. There are also metal case versions of all mentioned tubes. FYI the "red base rca's" were also the higher end tube, many having gold pins. Also, if a tube is marked "JAN" I have read that denotes military use.

[Cygnus X1]

Thank you devii.

I have several NOS 6SN7 GTA's and GTB's to choose from.
Tung Sol, RCA, Sylvania, "Japan". I have heard reports that they sound really sweet as a power tube. I really want to try this.

Football Sunday, the bench is on hold today...

[Cygnus X1]

So I have a 1 ohm, 10 watt resistor in linebetween the cathodes (tied together) and the bias pot.
The meter is reading "3" on the 200m DC range.

This reading doesn't change if I turn the pot.

I attached the meter from ground to the cathode, and I get a reading of 12VDC. This does reflect change when I dial the pot.

So,what the heck am I looking at here?

My B+ is showing 345 volts at the plate.

[GainMaster]

Thank you devii.

I have several NOS 6SN7 GTA's and GTB's to choose from.
Tung Sol, RCA, Sylvania, "Japan". I have heard reports that they sound really sweet as a power tube. I really want to try this.

Football Sunday, the bench is on hold today...

The Tung Sol tall bottles have great chime. A fantastic tube for a mini Wreck build, The RCAs are darker and better for Plexi, JCM 800 style build. The Sylvania are inbetween the two. All sound great as a power tube. Check here for a schematic http://www.ax84.com/4-4-0.html

It doesn't take much to drive the 6sn7 to distortion so a 12ay7 in the PI is just right.

Brian

[Cygnus X1]

Thank you again, Brian.
I started a new thread to try to clear up the confusion a bit.

Running it single ended, parallel.
I'll look at the Push Pull design later.