Fortin - Grind Pedal

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Fortin - Grind Pedal

Postby J0K3RX » 12 Oct 2015, 16:51

Ok, who's gonna cough up the $225.00 for this beast? :twisted: I love anything with Mike Fortin's name on it!!
http://www.fortinamps.com/grind/#
https://www.youtube.com/watch?t=30&v=gx0tSkPwDTY <--- Yikes!! :twisted:
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Re: ***Fortin Grind Pedal***

Postby gaskocher » 23 Oct 2015, 20:51

Someone please buy this, or I'll have to do it :twisted:

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Re: ***Fortin Grind Pedal***

Postby gaskocher » 30 May 2017, 07:42

There is a new version out without SMD which might be easier to trace.
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Re: ***Fortin Grind Pedal***

Postby Optical » 12 Sep 2017, 11:41

Image
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Re: ***Fortin Grind Pedal***

Postby andlord » 12 Sep 2017, 12:34

Awesome, any chance you can do high res pictures? Also the other side of the PCB would be lovely
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Re: ***Fortin Grind Pedal***

Postby snofla1900 » 12 Sep 2017, 13:58

Without SMD ? I must be going blind.

:P
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Re: ***Fortin Grind Pedal***

Postby Optical » 14 Sep 2017, 03:42

Not my pedal, justanother pic I found.
I was wondering if anyone is talented enough to trace circuit parts and perhaps recognise what was going on..
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Re: ***Fortin Grind Pedal***

Postby dv8r601 » 14 Sep 2017, 23:16

I have nothing but pure speculation, BUT all the metal guys love the Maxon OD-820. Its high headroom and YATS but they don't care. in reviews and In the page where the big pic came from the owner put it next to one and said it has a bit more output, and the tone more range, but sounds pretty close. My guess is a slightly glossed over (charge pumped )YATS with fixed gain and fixed dead center or (slightly)scooped tone section. Bigger output pot would affect Highs and volume a bit. Again, this is all conjecture based on the guts I've seen so far. I'm probably dead wrong, but this guess is based on Fortin using classic designs with a few novel twists. The guy gets Metal Tones better than almost anyone else.
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Re: Fortin - Grind Pedal

Postby Optical » 27 Nov 2017, 01:27

Looks like this pedal has three circuit sections.
LT607 voltage booster - appears straight from the datasheet
TC integrated pre - see the top left of the pcb there are the two transistors and diodes set up as a constant current source, part for part copy. Bass knob fixed
I'm not sure about the lower left portion of the pcb, maybe another filtered gain stage.

Image
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Re: Fortin - Grind Pedal

Postby J0K3RX » 27 Nov 2017, 04:01

Optical - I think you meant LT1054, right?
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Re: Fortin - Grind Pedal

Postby J0K3RX » 27 Nov 2017, 04:34

I think I like the 33 pedal a little more than the grind and the added remote channel swithing jack is just a damn good idea! I am really interested in the Zuul as well but, you won't see $230 coming out of my bank acct for any one of them!
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Re: Fortin - Grind Pedal

Postby Optical » 27 Nov 2017, 15:46

J0K3RX wrote:Optical - I think you meant LT1054, right?


Doh, yes :) http://www.ti.com/product/LT1054
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Re: Fortin - Grind Pedal

Postby Leito79 » 02 Dec 2017, 09:23

Optical wrote:Looks like this pedal has three circuit sections.
LT607 voltage booster - appears straight from the datasheet
TC integrated pre - see the top left of the pcb there are the two transistors and diodes set up as a constant current source, part for part copy. Bass knob fixed
I'm not sure about the lower left portion of the pcb, maybe another filtered gain stage.

[ Image ]


The Grind and the 33 are basically a TC Pre with a couple of tweaks to mimic and refine what Fredrik from Meshuggah was doing back in the day to boost his Mesa amps and make them sound tighter. As far as I know he used it with a higher power supply than 9V (as high the pedal could take without frying), bass at 0, treble at full (or almost), and I believe the volume was cranked as well. In the Grind you have the 1054 taking care of the higher voltage and then fixed bass and treble settings. According to someone in another forum, he asked Fortin about the voicing and he said something along the lines of "Slow roll off at -3db down from 1k. Everything else gets boosted with a slight bump. ", which I guess could be the lower left portion of the pcb you are refering to. The two bigger electro caps are rated at 50V, perhaps 100uF (or 1000uf???), I think the voltage is 24-36V, depending if you feed it with 9 or 12V. According to their datasheets the TL071 and LF356 can take up to 40V. The Opamp is sanded down, so we can´t know for sure, maybe it is a better/quieter/newer opamp or maybe not...The square capacitor on the left looks like a 1uF Panasonic (same value as TC), then next to it is a 10n, which is not a value that appears on the TC schematic, closest is 22n on the bass control...maybe that´s one of the mods Mike did to the original design. I wish there were more gut pics!!!!
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Re: Fortin - Grind Pedal

Postby mnemonic » 02 Dec 2017, 22:45

My original TC electronic integrated preamp has a UA741 in it. There's another schematic floating around that specs a 741. When I built a clone of it, I couldn't hear a difference between a 741 and a TL071, probably as the integrated preamp shouldn't be clipping the op amp, and it's not like guitar is a piece of hifi equipment.

I did try a Burr Brown OPA604 as well, and it did sound like it had more high end, a bit more 'hi-fi', maybe a bit more volume on tap? Probably nothing that couldn't be compansated for with different settings. I did leave the OPA604 in for the sake of my own cork-sniffery.

Regarding voltage, the higher the better. I run it at 30 volts (opa604 is good to I think 50 volts). Between 18 volts and 30 volts there isn't a big gain in headroom, but at 9 volts it clips a lot. 18 volts minimum is required in my opinion. So much clearer.

I think it sounds similar to the 33 demos I've heard if I turn the Bass to 0, and leave the Treble somewhere around noon. Treble at 10 is super brittle sounding, feeds back easy as it boosts a loooot of treble.

I did see a guy on another forum, I think rigtalk, say the 33 was just a TC integrated preamp clone with frederik's settings hard wired, but I didn't hear any comparisons yet. Apparently the Grind does sound a bit different though.
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Re: Fortin - Grind Pedal

Postby Leito79 » 04 Dec 2017, 07:14

mnemonic wrote:My original TC electronic integrated preamp has a UA741 in it. There's another schematic floating around that specs a 741. When I built a clone of it, I couldn't hear a difference between a 741 and a TL071, probably as the integrated preamp shouldn't be clipping the op amp, and it's not like guitar is a piece of hifi equipment.

Did you took any pics you can share? I´ve only came across a couple from the copper side only. Also did you checked it against any of the two schematics floating around? There is a couple of different values depending if you use 22K or 47k pots for the tone controls, there are at least two versions of the TC, with different pcb layouts and pot values...
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Re: Fortin - Grind Pedal

Postby mnemonic » 04 Dec 2017, 09:19

Leito79 wrote:
mnemonic wrote:My original TC electronic integrated preamp has a UA741 in it. There's another schematic floating around that specs a 741. When I built a clone of it, I couldn't hear a difference between a 741 and a TL071, probably as the integrated preamp shouldn't be clipping the op amp, and it's not like guitar is a piece of hifi equipment.

Did you took any pics you can share? I´ve only came across a couple from the copper side only. Also did you checked it against any of the two schematics floating around? There is a couple of different values depending if you use 22K or 47k pots for the tone controls, there are at least two versions of the TC, with different pcb layouts and pot values...


Yes, I snapped some pics, I had it open as I had to replace the 30-year-old electrolytic caps.

They're too big to attach here and I'm on my phone so I can't resize, hopefully this linking works:

http://i.imgs.fyi/img/212s.jpg

http://i.imgs.fyi/img/212u.jpg

http://i.imgs.fyi/img/212v.jpg

http://i.imgs.fyi/img/212w.jpg

i think there have been a few versions, for instance the schematic and vero layout on diystomps that I made my first clone from uses an A5k volume pot. In that config, it sounded exactly like my real one. For the second one I made (in a larger enclosure so I could fit a bypass switch) I used an A50k volume like the above schematic. Very small change in sound, maybe a bit brighter.

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Re: Fortin - Grind Pedal

Postby J0K3RX » 04 Dec 2017, 15:09

I believe you guys are right about the grind/33 being a TC Electronic integrated pre clone, makes sense :thumbsup

nice layout & scematic here..
http://www.rullywow.com/wp-content/uplo ... e-v1.0.pdf
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Re: Fortin - Grind Pedal

Postby Leito79 » 04 Dec 2017, 17:39

J0K3RX wrote:I believe you guys are right about the grind/33 being a TC Electronic integrated pre clone, makes sense :thumbsup

nice layout & scematic here..
http://www.rullywow.com/wp-content/uplo ... e-v1.0.pdf

Yes, I hope there was more pics of the insides of the Grind/33 to identify the cap values and we´ll be almost there!!! All poly ones can´t be seen in the pics, and there is at least one different value, the 10n cream MKT just below the Opamp IC, which i´m guessing belongs to one of the tone controls, since the treble control has a 4.7n and the bass has a 22n, which are the closest values on the whole circuit...I was familiar with that layout but never tried since it is double sided

mnemonic wrote:i think there have been a few versions, for instance the schematic and vero layout on diystomps that I made my first clone from uses an A5k volume pot. In that config, it sounded exactly like my real one. For the second one I made (in a larger enclosure so I could fit a bypass switch) I used an A50k volume like the above schematic. Very small change in sound, maybe a bit brighter.

Thanks for the pics! Did you checked the pot values on your original unit?Also seeing those red Wima´s on your original TC pcb reminded me of something...check out this pic of a batch of 33´s being populated, same red Wima caps
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Re: Fortin - Grind Pedal

Postby mnemonic » 04 Dec 2017, 19:43

Leito79 wrote:
J0K3RX wrote:I believe you guys are right about the grind/33 being a TC Electronic integrated pre clone, makes sense :thumbsup

nice layout & scematic here..
http://www.rullywow.com/wp-content/uplo ... e-v1.0.pdf

Yes, I hope there was more pics of the insides of the Grind/33 to identify the cap values and we´ll be almost there!!! All poly ones can´t be seen in the pics, and there is at least one different value, the 10n cream MKT just below the Opamp IC, which i´m guessing belongs to one of the tone controls, since the treble control has a 4.7n and the bass has a 22n, which are the closest values on the whole circuit...I was familiar with that layout but never tried since it is double sided

mnemonic wrote:i think there have been a few versions, for instance the schematic and vero layout on diystomps that I made my first clone from uses an A5k volume pot. In that config, it sounded exactly like my real one. For the second one I made (in a larger enclosure so I could fit a bypass switch) I used an A50k volume like the above schematic. Very small change in sound, maybe a bit brighter.

Thanks for the pics! Did you checked the pot values on your original unit?Also seeing those red Wima´s on your original TC pcb reminded me of something...check out this pic of a batch of 33´s being populated, same red Wima caps


Nice pic, looks like less SMD in the 33 than the Grind.

I didn't check pot value, I didn't want to chance desoldering them from the PCB, I'm still not very good at desoldering.

I did take a look at cap values in the unit, as there are some different values used based on the pot value. I did deduce what the values were, but I can't remember now, it was a few months ago and I can't remember now if they were 22k or 47k. I should have written it down.


Edit- never mind I did write it down, based on the cap values on the board, it has 22k neg log pots for bass and treble.

Both clones I built, I made with 50k bass/treble pots and the corresponding part values. So I guess whatever difference there is between the 22k pot version and 47k pot version is made inconsequential by the different cap and resisor values.
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Re: Fortin - Grind Pedal

Postby Leito79 » 04 Dec 2017, 22:44

mnemonic wrote:Nice pic, looks like less SMD in the 33 than the Grind.

I think the 33 is all thru hole components and uses the same wima MKT caps, maybe to preserve some "mojo" from the original (and maybe fredrik does not like smd). Grind is almost completely SMD

mnemonic wrote: Edit- never mind I did write it down, based on the cap values on the board, it has 22k neg log pots for bass and treble.
Both clones I built, I made with 50k bass/treble pots and the corresponding part values. So I guess whatever difference there is between the 22k pot version and 47k pot version is made inconsequential by the different cap and resisor values.

Exactly! So maybe the 10n cap I´ve mentioned before is actually the stock value and the Grind was cloned after a 22k pot version like the one you have

J0K3RX wrote:I think I like the 33 pedal a little more than the grind and the added remote channel swithing jack is just a damn good idea!

to implement the remote channel switching jack on the 33 you could use a 4pdt instead of a 3pdt for the switch (the extra row is used to make the amp switch channels), and a dpdt to toggle the polarity (NO/NC), pretty simple but useful!
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