DIY Proco Rat needs more bite

[pb3000]

I have a Rat breadboarded based on the tonepad.com schematic.  I've also researched the web, and bought and read Jack Orman's ebook on the Rat.  I'm really happy with the sound, but the "harshness" I hear often mentioned about this circuit or the trebly bite I hear on various youtube demos/reviews just isn't there.  Ie, when I've got the Filter knob all the way off, it sounds alot like what I expect or hear on youtube when demos have the Filter at 12:00.

I put a 15k resistor across the FILTER pot (in parallel) to attempt to give it a more useful range for me, since the vast majority of it was too muffled or bassy.  This mod gives a nice range on the bass end, but I wish I could get more trebly harshness on the other end.  To get a sound I like for lead, I have to setup the amp and guitar (Fender Jazzmaster) on the bridge pickup and about as bright a clean sound as I can stand.  Then I get a great sound I like - but it's lost if I use both pickups in parallel for a little hum cancelling.

I've paid attention to all Jack Orman's writings (his ebook focuses on how to tame the harshness) and basically done the opposite or not made a change on all his mods related to scaling back the bite of the circuit.

I have 3 different LM308s (2 canned and one DIP) and they pretty much all sound the same.  I've tried a 5534 chip also, but that just makes the whole thing squeal unacceptably when not playing and sounds lousy when playing.

Any ideas?  I appreciate any responses.

Thank you.

[GGBB]

Adding the 15K resistor is only going to limit the range of the filter control - it won't make the overall effect have more treble.  The RAT filter is a simple low pass filter and when it's "off" (filter pot value = 0) it passes all audible frequencies so playing with the filter probably won't solve your problem.  Which RAT schematic are you following?  Have you changed any components?  As you have observed, stock RATs normally have plenty of treble bite - my filter is usually set in the 1:00-4:00 range.  I'd suspect that something is wrong with the circuit you've built - maybe a component or two is out of range or misplaced - double-check all your components and the circuit build before anything else.