Anyone play with Bogner circuits?

[Gregg]

The plate voltage should be considered at the plate of 12AX7, not at the plate resistor node so even with 400V you'll hardly get 300V at the plate.
Higher value caps will pass more bass. Try it and you'll see.
Another two mods that came to mind is to replace the Treble pot which is log pot wit a linear one. Also someone reported that when coupling caps (currently polypropylene) are replaced with polyester ones the sound got smoother.

[Setneck]

The plate voltage should be considered at the plate of 12AX7, not at the plate resistor node so even with 400V you'll hardly get 300V at the plate.

I see. Thanks for the explanation. I was told to lower the 15k resistor from screens to PI which sets the plate voltage in XTC to 10k or even 4.7k. Soldano uses 10k, maybe that is the value I should go for at the beginning.

As You may know, the XTC has a plate voltage measuring plase marked from A1 to A5. On A5 I get 310V and that is why I though I exceed it. Where am I supposed to measure "real" plate voltage according to the particular preamp tubes? Should I do it on a tube sockets? Sorry for a n00b question btw

Higher value caps will pass more bass. Try it and you'll see.

Nah, so that's not for me totally . What is my goal is totally opposite

Another two mods that came to mind is to replace the Treble pot which is log pot wit a linear one

I've read about that on other forum that linear pot would open the tone. But it isn't easy to replace the pots in that amp I must say, especially because of a diodes glued to chassis...

Also someone reported that when coupling caps (currently polypropylene) are replaced with polyester ones the sound got smoother.

It could happen to be me. I've posted on other forums that I replaced all signal and coupling caps from polypropylenes to film-to-foil TAD/Mojo Dijon mustard clones caps. And indeed that change was ESSENTIAL to the sound. All harshness and grainy sound is now gone. What I got is smooth and more crunchy distortion. I can strongly recommend using those particular caps.

I have also replaced both bypassed caps with NOS Ero/Roederstein MKT1813, which gave me a very treblyish sound compared to the stock EVO MMK and especially tantalum.

[Gregg]

It could happen to be me.

It looks lite it was you.
This topic has been thoroughly discussed in the other forum. You'll hardly get more info here where high gain amps and stuff are not very popular.

[Setneck]

This topic has been thoroughly discussed in the other forum. You'll hardly get more info here where high gain amps and stuff are not very popular.

It was discussed indeed, I even tried to participate in that discussion . But I'm always open to every tips and advices.

Either way, thank You for Your time.

Regards, Andy