Mach 1 Overdrive mods?

[Flying]

Great, thanks.

The only time I used one was in the tone stack of my valve amp and that was because of the voltage rating.


But to be faithful, I'll get some in stock

 

[NickDanger]

These mods for goosing the gain up a bit are great! Love the slight mid girth the 220n cap got. One thing: what should I try if I want some more brightness? The tone knob maxed is a PERFECT sound, but there may be instances I’d need a little more high end on tap. A resistor/cap or maybe even just a different tone pot value?

 

[NickDanger]

Lowered C9 to 4n7 and it sounds great! Nice tonal palette.

 

[Tony_Pizza]

Hey people! I was thinking of doing some mods to this pedal where I increased the drive pot to 1 Meg and then added a switch to swap between the normal diode array and just two diodes in parallel. My ultimate goal is to bump up gain a bit and have the more aggressive and compressed clipping stage as an option to get more of a lo-fi and aggressive feeling from the pedal.

Down the line I may toy with the idea of adding a passive tone stack where I implement a high pass filter in conjunction with the low pass here that exists already (at least thats what I assume is there).

Any advice?

 

[Chuck D. Bones]

I recommend that you breadboard it before taking a soldering iron to a PCB.

 

[Tony_Pizza]

So update for anyone out there (echoes into space)... I decided to do a light mod in which I removed D2, D3, and D5 and left the gain pot alone. This fantastical new creation seems to be a tube screamer now? It has a low mid bump that I am not the craziest about, but the new more "compressed" clipping is cool and I like that part! Think a better idea would be to have a toggle switch to remove D2 from the circuit instead.

Onto "upping the gain" of the pedal. I did some math to calculate gain for swapping the 500k drive pot for 1M.

With 500k Gain max = 1+ (drive+R9)/(R11) = 154.30 aka 43.75db
With 1M Gain Max = 1+ (drive+R9)/(R11) = 304.73 aka 49.68db

What a bummer, if I were to do that mod I would only see an increase of about 6db!? Not quite the move here boys.

Rather than bumping that up and risk injecting noise with such a high value pot, I say we change the value of R11 to be lower instead!

Check this SH*T out. Let's see how much more gain we can get by going from 3300 to 1k.

With 500k Gain max = 1+ (drive+R9)/(1000) = 506.9 aka 54db Now we are talking!

I may even elect for something lower if that value doesn't cut it. Will update soon!

 

[Chuck D. Bones]

Don't forget to account for the effects of C5, C6, R12 and C7. If the low-pass (C7 & R9 + DRIVE) overlaps the high-pass (C5, C6, R11 & R12), then the max gain is reduced. Ever use LTSpice?

Also, not sure it was a good idea to hijack a 4+ year old thread. Why not start a new one?

 

[Brett]

Check this SH*T out. Let's see how much more gain we can get by going from 3300 to 1k.

With 500k Gain max = 1+ (drive+R9)/(1000) = 506.9 aka 54db Now we are talking!

I hate to burst your pepperonis, but I feel like your recent revelation may have been pretty well covered on page one of this thread:

Increasing the DRIVE pot to A1M will give 6dB more gain, which is not a lot. If you really want to goose it, then reduce R11 & R12, increase C5 & C6. I'd try 680R, 2.4K, 2.2uF and 220nF, respectively for a 14dB boost (with 500K DRIVE pot).