Any 6SN7 Guitar amps?

[Cygnus X1]

Thanks, all.

I'm neck deep in building the SEL.

[Cygnus X1]

Here is a link that isn't dead

http://www.ax84.com/static/october/AX84 ... 080601.pdf

I have built one and it sounds great. Currently working on a mini-Wreck.

Brian

Are those two gain pots, like on the SEL?
I finished my SEL, just cosmetics from here on out...
I'm really quite happy with it!

And...that canister cap...where do you find one of those?
I'd venture just building the power section into a doghouse, like I did on the SEL. Ir worked out fine.

[andrew]

Is a 6sn7 interchangeable with a 6sl7 ? If so I have a 6sl7GT that has 12vt heaters. How could I make it work for 6vt heaters? Thanks

[Phil_S]

Is a 6sn7 interchangeable with a 6sl7 ? If so I have a 6sl7GT that has 12vt heaters. How could I make it work for 6vt heaters? Thanks

6SN7 is like a 12AU7 and a 6SL7 is like a 5751. If you think 12AU7 and 5751 (or 12AX7) are interchangeable, the answer could be yes. But the truth is that they are only pin compatible, and not really interchangeable. Typically, nothing bad should happen if you interchange them, but you really shouldn't. If you have a 6SL7 with 12v heaters, then I guess it's a 12SN7? No, you can't run the heaters on 6v.

[GainMaster]

The mini wreck with 6sn7gtb is done. Schematic and sound clips here.

http://www.ax84.com/4-4-0.html

My build thread here

https://tubeamparchive.com/viewtopic.php?t=5504

Brian

[Cygnus X1]

The mini wreck with 6sn7gtb is done. Schematic and sound clips here.

http://www.ax84.com/4-4-0.html

My build thread here

https://tubeamparchive.com/viewtopic.php?t=5504

Brian

Wow...I have been looking at that one, Brian.
I have two SEL's built. I'm happy with the amount of gain, but want to
experiment with putting the 6SN7 in as the power tube.

I need to rewire the socket, and I think I can use the Weber I already am using. I can get the 250V b+, at 125ma. by switching the secondaries around. I hope to retain the gain, maybe get some power tube distortion as well.
Will this current rating be a problem for me? I don't think so, not sure.
AX84's schem shows a 60ma. It will only pull as much current as required, right?

How does the distortion level sound on the 4-4-0?

[Cygnus X1]

The mini wreck with 6sn7gtb is done. Schematic and sound clips here.

http://www.ax84.com/4-4-0.html

My build thread here

https://tubeamparchive.com/viewtopic.php?t=5504

Brian

Wow...I have been looking at that one, Brian.
I have two SEL's built. I'm happy with the amount of gain, but want to
experiment with putting the 6SN7 in as the power tube.

I need to rewire the socket, and I think I can use the Weber I already am using. I can get the 250V b+, at 125ma. by switching the secondaries around. I hope to retain the gain, maybe get some power tube distortion as well.
Will this current rating be a problem for me? I don't think so, not sure.
AX84's schem shows a 60ma. It will only pull as much current as required, right?

How does the distortion level sound on the 4-4-0?

[GainMaster]

Is a 6sn7 interchangeable with a 6sl7 ? If so I have a 6sl7GT that has 12vt heaters. How could I make it work for 6vt heaters? Thanks

No. One has much more gain than the other. Also, all 6sn7s are not created equal. Most handle only 300v or so like the 6sl7s but the 6sn7GTB versions handle 400+ making it a much better choice for a power tube.

Brian

[GainMaster]

Wow...I have been looking at that one, Brian.
I have two SEL's built. I'm happy with the amount of gain, but want to
experiment with putting the 6SN7 in as the power tube.

I need to rewire the socket, and I think I can use the Weber I already am using. I can get the 250V b+, at 125ma. by switching the secondaries around. I hope to retain the gain, maybe get some power tube distortion as well.
Will this current rating be a problem for me? I don't think so, not sure.
AX84's schem shows a 60ma. It will only pull as much current as required, right?

How does the distortion level sound on the 4-4-0?

Sounds like plenty of PT to me but the voltage may be a little low. The circuit will only pull as much current as required. We ended up running 340v on the 6sn7GTB.

The 4-4-0 has plenty of gain on tap with a nice classic AC/DC crunch at 5 with the beginings of a choppy modern edge to it. This is one of the few amps I have built that I didn't feel the need to put the gain on 10.

Brian

[GainMaster]

Are those two gain pots, like on the SEL?
I finished my SEL, just cosmetics from here on out...
I'm really quite happy with it!

And...that canister cap...where do you find one of those?
I'd venture just building the power section into a doghouse, like I did on the SEL. Ir worked out fine.

Yes. One gain pot is for the Bright channel and one is for the Dark channel. The can cap and mounting ring come from Antique Electronics.

Brian

[GainMaster]

Are those two gain pots, like on the SEL?
I finished my SEL, just cosmetics from here on out...
I'm really quite happy with it!

And...that canister cap...where do you find one of those?
I'd venture just building the power section into a doghouse, like I did on the SEL. Ir worked out fine.

Yes. One gain pot is for the Bright channel and one is for the Dark channel. The can cap and mounting ring come from Antique Electronics.

Brian

[Cygnus X1]

[Sounds like plenty of PT to me but the voltage may be a little low. The circuit will only pull as much current as required. We ended up running 340v on the 6sn7GTB.

The 4-4-0 has plenty of gain on tap with a nice classic AC/DC crunch at 5 with the beginings of a choppy modern edge to it. This is one of the few amps I have built that I didn't feel the need to put the gain on 10.

Brian

I can pull up to well over 450V at 125ma with the Weber.
It has no center tap, so I use a full wave bridge rectifier and it has worked great. My B+ for the SEL is at 350ish right now, so I guess all I have to do is rewire the octal socket to replace the 6V6 I'm using now for the 6SN7.
...Only thing I can't see is how the 6SN7 is wired!
I'm looking at the AX84 core 2 watt SE power amp, and it isn't registering how I am supposed to wire it. Where is the B+ coming in?

[GainMaster]

[Sounds like plenty of PT to me but the voltage may be a little low. The circuit will only pull as much current as required. We ended up running 340v on the 6sn7GTB.

The 4-4-0 has plenty of gain on tap with a nice classic AC/DC crunch at 5 with the beginings of a choppy modern edge to it. This is one of the few amps I have built that I didn't feel the need to put the gain on 10.

Brian

I can pull up to well over 450V at 125ma with the Weber.
It has no center tap, so I use a full wave bridge rectifier and it has worked great. My B+ for the SEL is at 350ish right now, so I guess all I have to do is rewire the octal socket to replace the 6V6 I'm using now for the 6SN7.
...Only thing I can't see is how the 6SN7 is wired!
I'm looking at the AX84 core 2 watt SE power amp, and it isn't registering how I am supposed to wire it. Where is the B+ coming in?

Don't use that schematic, use this one http://www.ax84.com/static/4-4-0/AX84_4 ... 081002.pdf

B+1 isn't used. The OT is connected to B+2. THe 6sn7 doesn't have screens so all the B+ comes from the OT. Your B+ may be high for the 6sn7. Cliff and Jon did a lot of experimenting before deciding on 340v for an optimal voltage. You may need to increase R2 to lower the voltage to the 6sn7.

Brian

[Cygnus X1]

OK, I see how to change to the 6SN7.
Not too difficult, add 1 resistor for pin 8, etc.

The 4-4-0 is push pull BTW...I'm using the single ended schematic.

One problem...I don't have a 2 watt bias pot.
The cathode bias from pins 3 & 6 go 1R/1W...VR1 is 1K/2W...then to
100R and 100uf to ground for the bias.

So, I guess I could use a 1K and adjust from there?
What value do I use to bypass the bias pot?

[GainMaster]

OK, I see how to change to the 6SN7.
Not too difficult, add 1 resistor for pin 8, etc.

The 4-4-0 is push pull BTW...I'm using the single ended schematic.

One problem...I don't have a 2 watt bias pot.
The cathode bias from pins 3 & 6 go 1R/1W...VR1 is 1K/2W...then to
100R and 100uf to ground for the bias.

So, I guess I could use a 1K and adjust from there?
What value do I use to bypass the bias pot?

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