251 schematic with 6S6B-v triode, launching the project.

[Murdock]

I got a 7:1 Bv11 in my M49c clone with 6s6b and the output impedance is around 200 ohm and has great bass response. So it works.
A 10:1 transformer would be more suitable for higher plate resistor and lower current.

 

[rock soderstrom]

I got a 7:1 Bv11 in my M49c clone with 6s6b and the output impedance is around 200 ohm and has great bass response. So it works.

That's good to know, thanks for sharing your experiences. What about distortion, do you have a comparison to a transformer with a higher step down factor?

A 10:1 transformer would be more suitable for higher plate resistor and lower current.

Yes, with 200K anode load a transformer => 10:1 would probably be more suitable

 

[rock soderstrom]

A 10:1 transformer would be more suitable for higher plate resistor and lower current.

I have just had another look at the data sheets. The 6S6B and also the 5718 are pretty current potent little beasts. The 6072 and especially the AC701 don't quite come close...

 

[Murdock]

That's good to know, thanks for sharing your experiences. What about distortion, do you have a comparison to a transformer with a higher step down factor?

Yes, with 200K anode load a transformer => 10:1 would probably be more suitable

I've got another pair of tube mics with 6S6B and 10:1 transformers but the circuit is slightly different (higher plate and cathode resistors) and the transformers are quite smaller compared to the Bv11. So I don't know how fair this comparison would be... But will check.