Ibanez MT-10 Mostortion kit for $40

 Update: The kit arrived. It is a Zendrive, not an OD-1. So more changes will be required. I might build it as a Zendrive to compare with my Rumble Drive. If it isn't better than the Rumble drive it will become a Mostortion.

Zendrive -> Mostortion conversion schematic:

This is the AliExpress Landtone Boss OD-1 with tone control kit (it says OD-1 on the PCB in the photo, that's how you know Edit: apparently not), almost exactly the same as a true bypass tube screamer. If you replace the tone control with a 3-band passive EQ and add an extra clipping diode, you get a Ibanez MT-10 Mostortion, which is out of production. The Danelectro Roebuck Distortion Pedal is a clone for $200. So this kit is good if you want a cheap copy that you can easily modify to suit your needs.

You need to be able to solder and to relate the schematic to the PCB. Some components will change, some will disappear, and the tone controls will have the new components soldered directly to them.

You drill 2 extra holes in the enclosure, and add new treble, middle and bass pots. Solder the new caps and resistors to the pots, since the PCB don't know what they are. Some components change, and the non-inverting input after the tone control is different. Replace 3 clipping diodes with 4 new ones and replace the opamp with the MOSFET opamp. Order the semiconductors and a bag of metal film resistors separately. And the capacitors, plastic film for the tone control caps, tantalum or electrolytic for the 1uF cap.

Here is the new schematic:


$25 for the kit shipped, $15 for the new pots and semiconductors.

Aion has a custom PCB with nice instructions, as does AMZ. For the extra $10 you get better instructions than you do here.

It's Alive!

Hot Harmonics

 My Hot Tubes/ Craig Anderton Tube Sound Fuzz variants from the '90s. Nowadays I would get the cheapest Aliexpress booster pedal (Kokko FBS-2), and tack the last 2 stages of the "Basic" arrangement onto the output. That would be about $US 20, and an hour's work.

Hot Harmonics:

"Basic" Hot Harmonics:

Hot Harmonics

This is the "House Pedal" - an overdriver/distortion/fuzz/octave up pedal. It's not a just a tweaked copy of something else, although it functions as a simplified Electro-Harmonix "Hot Tubes". No opamps, just a standard 1-FET booster to drive the CMOS inverters. Overdriven CMOS inverters actually sound a bit like a tube guitar amp, moreso than most opamp diode clipper circuits. I think. It's all the mind anyway.

A lot of distortion and volume from this thing, and I've reduced the gain from R.G. Keen's "Hot Tubes" schematic. I don't think the EH Hot Tubes was this hot (it used a CD4049BE, this may be the reason). The EH Hot Tubes is a guitar amp simulator. You have 2 inverting asymmetrical clipping stages, a tone control and a symmetricial clipping stage. This is a crude model of a push-pull guitar amp.

It does seem that the manufacturer of the CD4049UBE chip used makes a big difference. It's worth trying a couple of manufacturers. Harris (CD4049UBE H9801) and ST Microelectronics (HCF4049UBE W990A9828 MALAYSIA) work for me. I plan to try the CD4069 next (Ed Rembold's suggestion).

You can replace the input transistor with your favourite volume booster, a tube screamer, or an opamp as in the Guitar Player Anderton Tube Sound Fuzz. It does actually sound a bit like an overdriven tube amp. 


The Basic Hot Harmonics has about 15 components, which is almost as minimalist as it gets. There is no FET preamp stage, so the CMOS gain has been increased. Like a Fuzz Face, the pickup loads the input, reducing high frequencies (which is good). Turning the volume control down to about 7 takes nearly all the distortion away, giving a bright rhythn guitar sound.

It doesn't sound like a Fuzz Face of course, more of a "amp at 11" sound.

See also the Slow Finger on Aron Nelson's page.