using 40 VDC supply?

[Wind]

Hi

My first thread:
I have an old tube schematic (preamp) that runs on a 40 VDC supply using a 6J5GT tube from Pinnachle. Now I would like to connect that with a output tube (single triode) that also will run on a 40 VDC supply.
I have looked at the double triode 6AS7G, but i'm not sure thats the right one, also because I would like to avoid any bias circuit.
Any suggestions?

Wind

[Eli Duttman]

6J5 = 1/2 6SN7. 40 V. B+ seems UNUSUALLY low. Can the schematic be provided?

For low voltage service, the 3S4 power pentode can be considered. It's definitely a "flea". AFAIK, all triode power O/P tubes require a substantial B+ rail.

[Wind]

Hi

The schematic is provided in this post.
I know that when I lower the B+ the output power will be less, but thats also okay because it's only for a test. I'll see if a 3S4 tube can be used in my test.
In use of a 6AS7G tube, how will the it sound when I try to give it a B+ of 40 VDC?

Wind

[Cassiel]

In use of a 6AS7G tube, how will the it sound when I try to give it a B+ of 40 VDC?

What sound? Running the 6AS7 with that B+ you won't hear any sound....welll hum sound maybe.

[Eli Duttman]

Look at the 6J5 data sheet. The tube will work with a 90 V. B+ rail. It seems 40 V. B+ is wishful thinking.

If a low voltage triode is what you seek, check out the 6GM8/ECC86.

[SemperFi]

I agree 40V is a bit low, but for preamp purposes the 6AS7 will work with very low voltages. 6J5 will not. But you'll have very little gain, if any, most likely it'll function more like a buffer. 40V is a bit low, remember some voltage will be dropped over the Rk. Why do you want to use such low voltages in the first place? With a proper supply you can build something a little more usable.