McCrypt AT2 Distortion (Krank Maximus style clone) Schematic

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Manfred
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Post by Manfred »

"McCrypt" is an company label of the German distributer Conrad.
I bought the pedal at a favourable price.
I was thinking the pedal is defective, because it was bad sounding,
rather like a fuzz.
The schematic was not available at Conrad, therefore making it necessary to trace the circuit.
finally it is a Krank Maximus style Clone.
The reason for the bad sounding was the wrong biasing of the transistor input stage,
the output signal became heavily asymmetrical distorted at low input signal levels.
You can find the read DC-voltages on the schematics.
I increased the the value of R6 from 100 Ohms to 470 Ohms and made some further component changes
according the Krank Maximus and ProTone Pedals Body Rot II schematic.
It sounds great now.
Mc1.jpg
McCryptAT2ComponentSide.jpg
McCryptAT2SolderSide.jpg
McCrypt AT2 Distortion modded Schematic.JPG
McCrypt AT2 Distortion Schematic.JPG
McCrypt AT2 Distortion Mods.JPG
Shot with all the changes:
Mc2.jpg

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Nocentelli
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Post by Nocentelli »

:applause:


Why no thank button :scratch:
modman wrote: Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...

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Manfred
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Post by Manfred »

Nocentelli wrote::applause:


Why no thank button :scratch:
It's free! :)

I would have loved to buy one more pedal, but it is sold out in the moment.

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bool
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Post by bool »

Man, that "tone" section just dosen't make any sense to me.

From a quick calc, it seems that the scoop is centered around 110Hz (slightly bellow actually), which is rather low imho.

If you replace that 100nF cap with a 22nF; and the 10K resistor with a 4K7; you should get more in the 340Hz-ish territory which is imho more appropriate. (untested)

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Post by Manfred »

bool wrote:Man, that "tone" section just dosen't make any sense to me.

From a quick calc, it seems that the scoop is centered around 110Hz (slightly bellow actually), which is rather low imho.

If you replace that 100nF cap with a 22nF; and the 10K resistor with a 4K7; you should get more in the 340Hz-ish territory which is imho more appropriate. (untested)
Thanks for the hint, I will make first a test by circuit simaulation.

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POTL
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Post by POTL »

Strange schematic :mrgreen:
The capacitor 470n is clearly superfluous
Input resistance about 37K :shock: :slap:
I do not even want to take a day off
At a minimum, input and output buffers are needed
Tone control is terrible
:applause:

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Manfred
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Post by Manfred »

input resistance about 37K :shock: :slap:
I do not even want to take a day off
At a minimum, input and output buffers are needed
It is the same input circuit which is applied on the Krank Distortion Maximus and the ProTone Pedals BodyRotII Pedal,
both Pedals work fine.
Tone control is terrible
Ok, it could be much better but it works not too bad.
It is a mid notch filter with a center frequency of about 100Hz.
McCryptToneControlFrequencyResponse.jpg

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bool
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Post by bool »

Theres a slight contradiction in "mid-notch filter" and "center frequency about 100Hz".

As I suggested for this style pedals imho it would be worth upping the "mid-notch" to somewhere around 330-350Hz. But hey...

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Post by Manfred »

bool wrote:Theres a slight contradiction in "mid-notch filter" and "center frequency about 100Hz".

As I suggested for this style pedals imho it would be worth upping the "mid-notch" to somewhere around 330-350Hz. But hey...
You are right.

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Post by bool »

You can testdrive how the freq. change suits the pedal by simply (temporary) changing the 10k res. in the stack to 1k (parallel something to it f.e. a 1.1k resistor)

The eq curve wont be ideal, but massaging the eq usually takes time.

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