jtm cab sim bass boost needed

[AJS]

I have built the Marshall Cab Sim and I used the pcb http://home.worldonline.dk/jradmer/billeder/layout.gif (thanx for that one). http://www.diystompboxes.com/pedals/schems/msim.jpg

I have also made the http://home3.netcarrier.com/~lxh2/marshprb.gif lxh2 Marshall amp simulator.

Together these two sound very nice... BUT i think the cabinet simulator is a bit "thin" sounding and sometimes I feel that it would be nice to have "too much bass" available... What is your experience?
The cabsim is reported to have a lot of bass, maybe I made a misstake somewhere.

1) Can anyone think of some modification that I can do to the cabinet simulator make the bass boost (the 100 hz peak) more aggressive?
2) Am I making a mistake in running a single 9V battey with this design?

Best Regards