Firefly amp

[goldtopchas]

Hey, I've been reading the threads at the site for weeks and I'm really enjoying it. I'm a newbie at amp building. Done a few mods before though.
I built a "firefly" from the ax84 site. Has anyone here done one of these?
I asked a few questions there, but didn't get any response. So...it sounds good at real low levels, but if I turn it up past 2 or 3, it gets really "tubby" sounding. Like it's got way too much bass response. What pin or pins on the preamp tube would regulate the amount of gain and the overall tone. Or is there a cap. that controls the shelving of the bass? Any help would be appreciated. Thanks!
Oh, here's the layout. http://www.diyguitarist.com/PDF_File...flyChassis.pdf

[Bruce / Mission Amps]

Is there a schematic somewhere?
I don't know this circuit, but right off the bat it looks like thre grid of the first preamp tube is floating an that is a bad thing.

[goldtopchas]

As I mentioned, I'm a "newb" so I just used the layout. Here's a link to the schematic. http://195.178.227.103/ax84/media/ax84_m276.gif

The only thing I changed/added was a 120pf bright cap across the vol. pot.
My B+ voltages are within reason and I don't have any oscilation problems. It sounds nice up to about 2 1/2 , then gets very tubby sounding. Like it's got a big peak at about 80 or 100hz. If I can clean it up a bit , I'd be pretty happy with my first build.

Incidentally ..Thanks for the reply. Their doesn't seem to be much "traffic" at the ax84.com site. Or maybe they're ignoring me because I'm "the new kid on the block" .............sniff.

[Arthur B.]

It's possible you find the triode distortion to be bassy. You can clean it up by using the last stage as a split load PS That will increase the efficenncy of the output stage. Another option is NFB.

[goldtopchas]

Thanks for the suggestions, I'll look into possibly trying both.
I've heard some "clips" of other peoples builds of this amp, and although most complain of "not enough headroom", I don't seem to have any at all. But this design was meant for high gain/distortion and low efficiency/low volume.