Fortin - Grind Pedal

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temol
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Post by temol »

Yesterday I connected a 1kHz signal generator to the TC pre and checked input vs output signal using soundcard scope (Visual Analyser). Rather for fun than for scientific purpose :). But you can see the amount of amplification in the circuit.

All controls at noon.
all_noon.jpg
Volume max, low and treble at noon.
vol_max.jpg
Low max, treble and vol at noon.
low_max.jpg
All knobs maxed.
all_max.jpg
Treble at noon, vol and low at 15 o'clock.
low_vol_at_15.jpg
T.

Optical
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Post by Optical »

I built two TC preamps this weekend, one with the old values and one with the new values as set out in this post https://www.freestompboxes.org/viewtopic ... 20#p270383

I also gave them both charge pumps, they are running at about 30V. I have lots of tube amps and tried it with a bunch of them: Dual rec, SLO100, JetCity 22H, VH4, 6505+, BE100, Quickrod


This is my 2c: I can get all the tones the grind pedal gets, but this pedal definitely does not suit some amps; sounds awful and is way out classed by a tube screamer in most cases and generally. I think this is very much a meshuggah fanboi pedal and that's cool. But anyone thinking about one might consider they are getting caught up in the immense amount of fanboi hype around this pedal.

There is some discussion on another forum about voicing issue the pedal has, I wholeheartedly agree with the observations here http://www.rig-talk.com/forum/viewtopic ... 3&t=186560 and here http://www.rig-talk.com/forum/viewtopic ... 3&t=191604

What is does sound good with amps that are a bit muddy for modern metal: Dual rec, SLO, JetCity 22H
Sounds bad with most marshalls, friedman
Sounds ok but nothing special with the splawn 6505+ and VH4. Those are tight amps already but still can be boosted for a different texture, i think i'll stick to the tube screamer circuits though.

Another observation is the pot tapers are make the controls pretty odd and very touchy around the sweet spot - I think linear pots might suit better but I havent tried that yet.

All up, a tube screamer or similar is far more versatile when set up as a clean boost, probably a timmy pedal could be dialed in to sound about the same. But if you have a muddy amp like a dual rec or SLO, then the TC pre/grind can be useful.
Last edited by Optical on 22 Jul 2018, 01:24, edited 1 time in total.

Optical
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Post by Optical »

Anyway, I built two pedals so I can tweak one and A/B it against the other.

First thing I did was add a LPF to the output, currently experimenting with 47-100nF across the output. That kills a bit of the noise

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Post by DevouredDeth »

Any success with reverse engineering this? I put mine on the backburner after a few changes I will say I did not put much more effort into a pedal I am curious about trying.

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Post by mnemonic »

Pedalpcb has a pcb for the tc pre now, with charge pump.

https://www.pedalpcb.com/product/integralpreamp/

I got one yesterday, just need to order parts next.

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temol
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Post by temol »

Fortin 33 based circuit is available from a PedalPCB. Very similar to the TC preamp, minus bass and treble as potentiometers.
I have it on a breadboard now. 32V from a charge pump, no clipping so far. Maybe adjustable EQ is causing clipping issues and that's why 33 has fixed eq.

T.

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