PEARCE G2R schematic - channel 1, what's happening here?

[J-fish]

Hello!
It's been a long, long time I started to analyse the schematic of the Pearce G2R, which I have.
This amp is considered one of the "holy grail" SS amps ever produced, so I thought that my doubts could be of some interest for someone here, also because I think it's been copied in pedal form during the years for some well regarded working musicians.
This is the schematic I found on the web:
http://www.travis-hartnett.com/Pearce_A ... n=download

Now, what I see is something I really don't understand in the channel 1, the most crunchy/distorted/high gain of this project.
If you look at the 2nd opamp of channel 1 (just follow the signal path from the Input A), there is a high pass filter formed by the 22k resistor and the 0.0068 uf capacitor; this one should make for something like around 20 dB of mid boost at 1khz, more or less;
then again, you have another high pass filter at the 4558 opamp just after the 3280 OTA, the high pass filter formed by a 10k resistor and 0.0039 capacitor....this should make for another pretty big boost of mids and treble.
Then, you have another whopping high pass filter just after the active eq section, again, around a 4558 opamp, the one just after the Volume knob...this one is formed by 4.7k resistor and 0.0039 uf.

How can all this be?
Honestly, I'm definitely not hearing all this high mid/treble tone from this channel.
Could someone please help me understanding this distortion channel? Please, please...! I'm feeling pretty discouraged
Am I missing something?
Thank you very, very much in advance to everyone who will write something about this.

[teemuk]

For "modern" high-gain designs it is customary to attenuate / filter out majority of lower frequency signal content in order to decrease intermodulation distortion. Yes, many modern high gain design have a significant gain peak around lower mid-range frequencies, e.g. 1 kHz.

Yes, it sounds rather high if you consider that low E is 82 Hz but it also results to that "tight", modern metal tone with decent note separation. Leave lower frequencies unfiltered and clipping distort at whole effective bandwidth of the instrument and you get that "mushy", 1960's "fuzz" distortion, which sounds more like farting and where you don't hear much of upper strings when you simultaneously pluck a lower string. You just get that farty "BRRRR" instead of that tight metallic "TWANG!".

Instrument's tone and timbre is defined by harmonics. When you pluck a guitar string you get the fundamental harmonic frequency and wealth of others, which make guitar sound more intersting than plain sine wave tone. In fact, make it sound like a guitar in the first place. Fundamental is not always the most important frequency to convey because information of what note is plucked is also conveyed by other harmonics within the signal. And for modern high gain tones we don't generally need much low frequency content to distinct the most vital pieces of signal information.

High gain distortion is largely result of accentuated higher order harmonics. In similar manner, timbre of high gain tones is centered around this higher order harmonic content. When we pluck low E (82 Hz) we don't need to hear 82 Hz at full amplitude, it's enough that SOME harmonics of 82 Hz have enough amplitude to be heard, even if those harmonics are significantly above 82 Hz. And when one "high gain" distorts a signal it's going to generate a wealth of higher order harmonic content.

Another aspect is that excessive "brightness" is also filtered out by the design: A generic guitar speaker may not generate much noise above 5 kHz (its a very steep LP filter too) and pre-emphasizing before distortion may also low-pass filter to some degree because harmonic distortion is going to "revive" that higher order content nevertheless. It's like turning down "Tone" control from your guitar and running to high gain effect: The end result doesn't sound all that "dark" because harmonic distortion accentuates those higher order harmonics that pre-emphasizing attenuated.

Additionally, high gain amps may introduce bass boosting POST distortion. This way you get true emphasize on lower frequencies but sans intermodulation products that would be result of low frequency boost BEFORE distortion.

[okgb]

I have nothing to contribute though thanks for posting that

having Holdsworth endorse it for a while adds some validity, He's no shill [ though he seems to get his sound from anything ]
curious " mere " clipping diodes in the second opamp fb loop but with more tonal options ?