increasing impedance in the first stage of a FET based overdrive

[mordechai]

As I mentioned in an earlier post, I'm having trouble running a fuzz face into an overdrive I made...one with a JFET booster similar to the Fetzer Valve as the first gain stage which then feeds a subsquent two FET stages into breakup.  On its own, the thing sounds very nice, like a dirty Fender Champ.  But when I hit the fuzz circuit going into it, the fuzz signal is "clamped", and some notes just do not bloom/blossom...they sustain and are dark, but not wooly.

Is this an impedance issue?  A fellow traveler suggested sticking a buffer between the units, which I think would work, but I wonder if there's something I can do to the input of the overdrive itself if this is a matter of impedance so that it can take, directly, a fuzz signal going into it.  Could this be remedied by upping the 1M pulldown resistor at the front of the Fetzer-type boost stage to something higher, like a 2.2M?  Right now, the boost-stage input has a 1M pulldown resistor, a 68K series resistor, and a 100pF-to-ground cap. 

Again, as is, it sounds great and boosts the following two JFETs into a very nice overdrive, so I'd like to retain those characteristics while having this initial stage be more fuzz-signal friendly. 

[WaveshapeIllusions]

You may want to consider shorting the 68k. I believe that brings the impedance down. The 1M, on its own, should be high enough.

[Kesh]

the 68k just goes to the FET, which has a very high impedance, so it won't be that. in fact i'd doubt it's an impedance issue because it is a fet on the input.

buffers are often fets, or fet input op amps.

is the fuzz face a +ve ground one?

[Gus]

What Fuzz volume control are you using a 500K or 100K? 
I will guess it is a 500K?

[ashcat_lt]

It might just be that this is what it does.  Sometimes distorting an already distorted signal just isn't as awesome as you might think.  Once you've got a square wave you can boost and clip all you want and end up with the same square wave.

Might be you need to attenuate and/or highpass the fuzz signal in order to give the following box something it can work with?

[mordechai]

Thanks for the helpful replies.  First...it is a positive ground fuzz (tradition fuzz face), with a 250ka volume pot.  Second, I should mention that the "clamped" effect is only there when the overdrive isn't at full gain.  When I max out the od's gain pot, everything works well. 
Third, I wired up a similar overdrive I cooked up where the first stage is a MOSFET (with 1M bias resistors btw the drain and gate and the gate to ground) and encountered the very same problem...a clamped dull fuzz tone on many notes unless the OD's gain was at max.

[Jazznoise]

That's where a different flavour of distortion can be useful. Look at something like the Machine or an Octavia, where you can introduce other cool artifacts that don't rely on clipping!

[mordechai]

Actually...mystery solved.  The Fuzz Face circuit wasn't biased correctly.  I tweaked the knob and whammo, fixed.  But the overdrive still muddies the sound a bit, very much like the ZVex BOR used to do when I would run a fuzz into it.  I'm going to try to futz with the coupling caps and see what I can do to change that, so that less low end gets amplified.  Maybe a smaller input cap is a good place to start.

Anyway, thanks for chiming in everyone, I appreciate the help.