Best bias for 6cg7

[rossdt]

Hello!
I decided to use a 6cg7 for a Schmidt Phase Splitter. I am still undecided on the choice of the quiescent point. What is the best? Please, help me!
Alessandro.

 

[Tubes4e4]

Hi Allessandro,

6CG7 is a 6SN7 in a noval envelope (slightly derated plate Pd, but this doesn´t matter for your app).

Thus, any Schmitt splitter designed for 6SN7 should give suitable operation point suggestions.

For an example, see p670 of RDH4 (ECC32 = 6SN7).

Tom

 

[Giaime]

(ECC32 = 6SN7).

Really? I heard this many times but specs in the datasheet look very different. In fact, recently I designed a schematic for an ECC32 + #50 amp and the builder tried to put 6SN7 in it, and it didn't work, voltages were all wrong.

 

[Tubes4e4]

Hi Giaime,

regarding ECC32 = 6SN7,

Really?

at least the german "Röhrentaschentabelle" says so.

But you are right: Glancing over the specs sheets, data is not identical, I agree. But not very much off either.

For the Schmitt splitter app under discussion, the mentioned RDH4 example still should give a good starting point for 6CG7/6FQ7 or 6SN7 usage.

Tom

 

[Geek]

ECC33 is closer though to 6SN7

https://www.tubeworld.com/6sn7.htm

Isn't it?

 

[rossdt]

Better 6CG7 or 6SN7?