G1 - The clean version pedal mod

[Elijah-Baley]

Hello everybody, my first post here.
I really like the three circuits Malachite Overdrive, Tyrian Distortion and Sanguine Distortion, and I planning to build all of them, even if I don't know when.
I also have an idea but I don't know how much good is, maybe it's totally stupid. But I would like use the replica G2/G4 PCB to create a sort of G1 clean version pedal.
How you would do it? Tweaking the gain stages or jumpering them totally...

Thanks!

 

[Chuck D. Bones]

I think there is an easier path to a clean preamp / boost. Take a look at the clean and low-gain pedals on this site, go find some demos of the pedals that they replicate and see if you find one that does what you want. The TC Electronics Integrated Preamp, for example. The Chela can be easily detuned to get a clean boost.

Just my $0.02 ±5%

 

[Elijah-Baley]

Thanks, Chuck.
Probably there are some nice clean boost with eq I could use for my target. I thought even to the ROG Tonemender, but it has a amp-like eq.
The Chela could be ok changing something, as you said. Its Baxandall three bands is ok, but I wanted something more close the the series of the gain pedal I mentioned early.
I would try to keep the same eq: a two band Baxandall plus a Mid control.

 

[Robert]

If you're dead set on a "cleaner" version of the circuits mentioned above...

Start with a Malachite PCB
Omit the clipping LEDs
Reduce R8 to 10K
Possibly reduce Gain pot to B500K

If you already have an assembled Malachite you can test most of this (except for omitting the LEDs) by jumping a 22K across R8 and a 1M resistor across the lugs of the Gain pot. It'll affect the taper of the Gain pot but you'll at least be able to get an idea of the max gain on tap.

 

[Chuck D. Bones]

You can leave R26 & C23 out, they don't do anything. I'd increase R23 to 100K so you're less likely to overdrive the last stage when the tone controls are dimed. If it's too dark, take out C14. If it's still too dark, take out C7 also. C7 and C14 are there to smooth out the LED clipping. If the LEDs are gone, you might not need those two caps. This could take some experimentation to dial it in.

 

[ErickPulido]

You can leave R26 & C23 out, they don't do anything. I'd increase R23 to 100K so you're less likely to overdrive the last stage when the tone controls are dimed. If it's too dark, take out C14. If it's still too dark, take out C7 also. C7 and C14 are there to smooth out the LED clipping. If the LEDs are gone, you might not need those two caps. This could take some experimentation to dial it in.

Out of curiosity, does the R26 & C23 can be omitted on the G4 as well?

 

[Chuck D. Bones]

Yes, on the Sanguine board they are called C22 & R27. On the G3 (Tyrian) C23 & R30 create a 1dB rise below 1KHz. Barely audible under the best conditions. Not sure why Revv put them in there.

 

[Elijah-Baley]

Thanks a lot to everybody! I didn't build the Malachite nor the Sanguine, still not. But I like program everything with much time in advance.

I'll try all the suggested mod on my emulator software. This is what I can do, now. I have not too much material to emulate it, just the frequencies and a guitar sample, just to have an idea of response of the sound.
Meanwhile, I tried something by myself: omit the LED, the gain pot mod... I'll let you know what I get, even if it's not the circuit in the real life.
I guess I have to pay attention to the overall volume, because omitting the LED rise up the volume, but some cut of gain maybe will cut the output.

 

[ErickPulido]

Yes, on the Sanguine board they are called C22 & R27. On the G3 (Tyrian) C23 & R30 create a 1dB rise below 1KHz. Barely audible under the best conditions. Not sure why Revv put them in there.

Thank you so much

 

[Elijah-Baley]

I'm trying to emulate the schematic of the G2 with some mods.
1. Omitted the LEDs
2. Reduced R8 from 22k to 10K
3. Reduced Gain pot from 1M to 500k. But I setted it on 0.

Just a few of mods and the my clean guitar sample sounds clean at 0 gain. Maybe just a little bit less loud. But that's not a problem: the Volume pot is setted at 50%.
With the gain at max the sample sounds louder, not too much, and a get little bit of break up. Nothing bad with it.

We should see how will sound the real thing, but it could be a good starting ponit.

About other mods like R26 & C23, I tried to leave out in the original G2 schematic, and indeed doesn't change anything. The difference is just a tiny gain/volume loss of 0,2db in a large wide of the central spectrum. I'd leave it in anyway.
About C7 and C14 I'll keep in my mind both. In the modded version if I leave out just C7 I can hear a bit of more high frequency, but I have to compare when I will built it and see how much difference there is betwenn the effect on and the bypass, to make it more transaprent possible (even if the effect has an eq, of course). It could be useful use C7 or C14 to create a Bright switch.

 

[Elijah-Baley]

Hello, I'm back on it, finally.
I built the circuit of the Malachite / G2 stock and I like it. It's a nice overdrive.
I have some parts on socket so I made those experiments to get a clean preamp.

I replaced R8 22k with a 10k. The effect is considerable: this makes a noticeable volume and high frequency loss, and I don't lose too much distortion. Leaving out the LED I get just a bit of volume boost.
Leaving out C7 10nF and C14 1nF it's not enough to avoid all the treble cut. The same about C5 47pF.
I didn't change the 1M Gain pot just because I can't set at min value to test the sound, and even low setting cut a bit of volume.

What I get after all these mods is a dirty sound at half gain setting and a clean sound at min gain setting, but it's a bit muddy and the volume loss is still too much.
I increased the volume replacing R23 15k with a 4.7k.

Anyway, there is another problem about the volume loss. Increasing the volume thanks to R23 or just through the Volume pot I realized that the background noise is rise up. Indeed, with the toggle switch set at center, the softer mode where we have a drop of volume I notice, indeed less volume, but the noise is the same.
Paradoxically, I got more noise with this new clean sound than with the stock overdrive sound, because the volume is lower, but not the noise.

I'd like to keep to argue about the possible mod of this circuit, even if I don't want to mess up too much the board. Maybe I'll do next time with a new board.
I didn't touch the first stage, maybe I can boost a bit without get more distortion.
I didn't socket C8 1nF, but maybe I could take off this, too, to rise up some treble.
How much can help decrease the ceramic caps 120pF?

 

[Elijah-Baley]

Hello.
I tried some mods to make it a clean pedal, but the thing is not been a success, and I gave up for the moment.
So, as I wanted to do, I finish my board (stripboard layout) to make the Malachite schematic. Today I soldered the last parts I tested, and like my last test it worked ok, I think.
I have a question about the Malachite (G2) pedal, now: when I low down the volume guitar I lose treble, even with my PRS SE with the Treble Bleed mod. This seems never been a problem with other overdrive/distortion pedals, using at least the PRS.
Is it normal with this circuit?