9V Electric mistress - TPB volume drop compensation, input buffer really needed?

[Ptron]

This seems to be an ongoing issue discussed around here: the 9V Electric Mistress has a significant volume drop when used with TBP.

http://www.aronnelson.com/DIYFiles/up/9V_Mistress_project_file_v11_update.pdf
or
http://www.tonepad.com/getFile.asp?id=102

If it's going to be TBP, isn't that buffer stage pretty useless? Would it be a problem to ditch the buffer and use the opamp section for a gain recovery stage at the end of the circuit? Maybe I'm not figuring this right but the input impedance of the following stage looks to me to be even higher than the buffer stage.

Also, an oft asked but never answered question is...Why the flip is power supply like that?!? What is the 200ohm PS resistor for and why does the battery stay connected (via the 2k7 resistor) when an power supply is used? So it can charge a battery? (as someone suggested)

Some links to other 9V EM  threads:
http://www.diystompboxes.com/smfforum/index.php?topic=54433.0
and courtesy mudmen:
http://www.diystompboxes.com/smfforum/index.php?topic=44582.0
http://www.diystompboxes.com/smfforum/index.php?topic=46713.0
http://www.diystompboxes.com/smfforum/index.php?topic=46519.0
http://www.diystompboxes.com/smfforum/index.php?topic=48992.0

[markusw]

If it's going to be TBP, isn't that buffer stage pretty useless? Would it be a problem to ditch the buffer and use the opamp section for a gain recovery stage at the end of the circuit?

Might be a cool idea! 
I just did a simulation it LTSpice and if you replace the buffer stage with a 10µ you get the same freq response for the whole guitar range.
Maybe there are other issues......don't know

Markus

[Ptron]

I was kinda thinking in one direction when I posted this. One difference would be that the source impedance for the 2nd stage could be high if the first stage was eliminated,  so the buffer stage isn't really useless, BUT... the question still stands. Is it really necessary with true bypass and post effect gain compensation?

[Ptron]

I also wonder if playing around with the 13k, 8k2, and 510 could help with the volume drop? Not much interest here, it looks like. Guess I'll have to get off my lazy ass and actually breadboard the thing and find out. Sigh. I'll post my results when I get around to it, could be a while.

Any takers on the why's of the power supply?