807pp + input phase splitter

[lcsaszar]

Is it related to the fact that Vg2=300V, Va=600V max according to the spec sheet, and 300V is too low B+ in triode mode for getting optimum performance?

 

[emk2]

paraphase ?

Hi

I received the silver mica's caps, 100pF to 1nF for the input PI trans (Sowter 8920). It didn't cure the problem, still ringing.. just for testing purpose I tried with a LL1681 (MC input transformer not intended for this use), all is well, no ringing, sinewaves, triangles, even squares are clean.

Now I would like to try an old and simple PI, the paraphase. This one seems to be a little bit different. 1M in // of the 270K and connected to ground through the 270K.

Any comment ? no pot needed to adjust the gain of the second half triode ?

Is this PI dangerous in case of overdriven PP ?

Last question, generally speaking, does a PP triode connected has interest ? every time I tried UL, it sounded better to my ears, despite the DF issue (no feedback yet).

OPT are from Quicksilver mini-mites, good ones ?

Thanks.