PPIMV question

[deiseldave]

I'm probably making an error in how I'm thinking the PPIMV works. I am thinking that by turning the pot counter-clockwise, I am reducing the resistance to pin 5 of the output tubes. But, that is also lowering the volume. How can lowering the resistance, lower the volume? I would think that lower resistance would mean an increase in current, and the volume should go up. Sorry if this is a stupid question. But, I am trying to learn, and really don't get it... Thanks in advance for help.

[gingertube]

By turning the MV counter-clockwise what you are doing is "picking off" less of the signal voltage from the phase splitter and that means less drive to the output valve, hence less volume. The lower resistance is not important except for its part in the voltage divider (of the phase splitter signal output voltage) action.
As you turn up the MV (Clockwise) you pick off more and more of the phase splitter signal and thus increase the signal voltage drive to teh output tubes, until you get to 10 on the dial at which point ALL of the phase splitter output signal goes to the output tubes and it acts just as if you did not have a PPIMV at all.
Hope this explaination helps.

Cheers,
Ian

[deiseldave]

Thanks. I will have to study on your response.
Truthfully, I think my real problem is that I don't understand the basics of the PI -> Power part of the circuit. I need to find a PI for dummies book, or something.
I guess the question I should have asked, is for a recommendation for a link to tutorial on how the PI works.

[Structo]

A great book for intermediate and experienced alike is Designing Tube Preamps for Guitar and Bass by Merlin Blencowe.

He made a second edition which is what you should get.

Lots of good information and about different kinds of phase inverters.

http://www.amazon.com/s/ref=nb_sb_noss? ... 20Blencowe

[deiseldave]

I'll order that book. Thanks.