- Build Rating
This circuit - the Ibanez MT-10 Mostortion - has had some hype on gear forums, after some Nashville super-player hype (similar to how the hype for the Nobels ODR-1 got its start). AionFX does a great writeup on this circuit on the Quantum MOSFET Distortion product page. Incidentally, I actually built not one, but two Aion Quantums many years ago. That was back in my early days of pedal building - it may have been the first pedal I built that wasn't from a kit. Those worked great, but I sold them.
So why circle back to this circuit? I recently built the Cast Iron Overdrive, intending to use it for the dirty boost/edge-of-breakup role on my board - as I mentioned in my build report, that mids control is the killer feature that gives it tremendous flexibility. And while the Cast Iron is indeed great, it made me wonder how it would compare to the MT-10/Quantum/Oxide. PedalPCB ran a sale and that seemed like the perfect excuse to satisfy my curiosity!
I took a few liberties with this build, some due to being limited to what parts I have on hand, and some intentional:
I got it boxed up and plugged it in. My custom relay bypass worked, and it bypass mode worked. But when I engaged it - no sound! Nothing at all. I had that sinking feeling I was going to have to debug. At this point, I hadn't put the back cover on, so I flipped it to see if there was any obvious mistake, and indeed there was: I forgot to install the opamp! The original uses the rare (and expensive) CA3260 opamp. Everything I've read says that in this circuit, except maybe at max distortion, the opamp doesn't have any impact on the sound. So I used a good ol' 4558.
Once my brain fart had aired out, everything worked great! It sounds great. It can do the transparent thing, similar to the Cast Iron. I doubt anyone could tell a difference in a band mix. The three band EQ is quite useful, despite being entirely passive. All-in-all, I don't think it will blow anyone's mind, but the three band EQ makes it very flexible, practical and versatile. A good "utility" pedal that I think most people could get a lot of mileage out of.
The finish is yet another Envirotex (epoxy resin) over mandala stickers.
The knobs deserve special mention: they are aluminum 1510 and 1900 clones. As I mentioned in my revised Hard Rock Pinnacle build report, I don't think I can ever go back to plastic knobs. I'm now a bona fide knob snob!
So why circle back to this circuit? I recently built the Cast Iron Overdrive, intending to use it for the dirty boost/edge-of-breakup role on my board - as I mentioned in my build report, that mids control is the killer feature that gives it tremendous flexibility. And while the Cast Iron is indeed great, it made me wonder how it would compare to the MT-10/Quantum/Oxide. PedalPCB ran a sale and that seemed like the perfect excuse to satisfy my curiosity!
I took a few liberties with this build, some due to being limited to what parts I have on hand, and some intentional:
- C5: I used a 180nF cap instead of 220nF, this controls the bass roll-off (i.e. high pass) before the clipping stage - a smaller cap raises the frequency, so I bumped it up a bit here to hopefully avoid some potential muddiness
- The clipping diode arrangement is two series-pairs of 1n4148; I used on ba282 diode for a hint of asymmetrical clipping
- C4: I used 56pF instead of 51pF because that's what I had on hand
- C1: I used 27nF instead of 22nF because that's what I had on hand
- For the drive pot, I didn't have an A500k on hand, so I used an A1M with a 1M resistor across pins 1 and 3
- Used an RC4558 opamp instead of CA3260
I got it boxed up and plugged it in. My custom relay bypass worked, and it bypass mode worked. But when I engaged it - no sound! Nothing at all. I had that sinking feeling I was going to have to debug. At this point, I hadn't put the back cover on, so I flipped it to see if there was any obvious mistake, and indeed there was: I forgot to install the opamp! The original uses the rare (and expensive) CA3260 opamp. Everything I've read says that in this circuit, except maybe at max distortion, the opamp doesn't have any impact on the sound. So I used a good ol' 4558.
Once my brain fart had aired out, everything worked great! It sounds great. It can do the transparent thing, similar to the Cast Iron. I doubt anyone could tell a difference in a band mix. The three band EQ is quite useful, despite being entirely passive. All-in-all, I don't think it will blow anyone's mind, but the three band EQ makes it very flexible, practical and versatile. A good "utility" pedal that I think most people could get a lot of mileage out of.
The finish is yet another Envirotex (epoxy resin) over mandala stickers.
The knobs deserve special mention: they are aluminum 1510 and 1900 clones. As I mentioned in my revised Hard Rock Pinnacle build report, I don't think I can ever go back to plastic knobs. I'm now a bona fide knob snob!
