Master Vol pre-Pi/post third stage is Baned??!

[richon]

Master Vol pre-Pi/post third stage is Baned??!

Has anyone tried it ?

I'm going crazy modding a Fender-ish amp with what was a dumble Overdrive which wasn't for me

[sepulchre]

I've got one in mine. But it's my first build and it's not exactly a TW clone - some differences. Plus I don't even have it voiced yet. But I can tell you, to get "the tone" I have to turn the master all the way up.

Edit: mine doesn't get "the tone" even with the master cranked. I have to remove it and even then it's got problems. So...

[Firestorm]

In that circuit, pre-pi master affects the tone. Post-pi master affects the nfb. Incredibly complicated subject, which someday I may attempt to understand.

[pablogt]

I would try to put in IN the PI. That is, a bootstrapped mv....
Pablo

[hans-jörg]

I would try to put in IN the PI. That is, a bootstrapped mv....
Pablo

Hello Pablo,
sry about this question, but do you have a schem with a bootstraped MV ?

Sounds interesting but I have no idea how it looks. All I find is "kathode amplification" or "anode basis circuit"

Best

Hans-Jörg

[pablogt]

I used it on my Plexi.
https://tubeamparchive.com/viewtopic.ph ... ight=plexi

Very transparent...

Pablo

[martin manning]

I used it on my Plexi.
https://tubeamparchive.com/viewtopic.ph ... ight=plexi

Very transparent...

That's a great looking amp, Pablo! Where did the bootstrapped MV (dual pot version) come from? I looked at a bunch of MV discussions, including the one here on TAG ( http://www.ampgarage.com/forum/viewtopi ... highlight= ) but I don't believe I saw a source for that one.

[pablogt]

I read about it first in Kevin O'Connor's books. Merlin also talks about it in his books.... Tried it and loved it.
Pablo

[martin manning]

This MV is not in Blencowe, but he does discuss the "scale" control. I read that O'connor was the source of the circuit with the single 1M pot on the input side, but didn't see anything attributing the dual to him.

[pablogt]

He calls it "London Power improved master volume" or something like that.

P.

[martin manning]

Ah, thanks!

[Reeltarded]

Interesting setup there. I noticed it in your build thread before but never looked so close.

[hans-jörg]

Thank you Pablo,

I see now, its the "alternate drive compensation" of London Power Scaleing.

But does it work with the same "transpiracy" in a Rocket without P.S. ?

I will give it a chance, but first I´ll try with LarMar (the 2x250k is allready in and waits) and compare it than with the L.P.

Thanks again

Hans-Jörg

[pablogt]

Actually, I prefer the Lar Mar ppimv in the Rocket. They have no NFB loop, so NFB does not decrease when used

P.

[hans-jörg]

I understand. So if NFB is a matter better the bootsraped PI version.
If no NFB - the LarMar is the solution.

Merci

Hans-Jörg