MXR Custom Badass Modified OD

Here's another one I was surprised I hadn't drawn up before. Like the Custom Badass '78 Distortion, it's also based on an old Boss pedal—the SD-1. (Or I guess you could say it's a modified version of the Zakk Wylde Overdrive, but that's based on the SD-1... Either way, it's definitely been modified with the added 100Hz control and the Bump switch. Here's the schematic for reference. Should fit nicely in a 1590B.

Lighthaus

Someone requested the Openhaus which, to be honest upon pulling up the schematic, made my eyes glaze over. It's big. But I came across a stripped down version on Sabrotone and it felt much more doable. So here you go! It'll fit in a 125B with top mounted jacks and both footswitches. I'll leave the method of the voltage doubling up to you.

Noah'sArk Distortion M

Not a lot out there on this one, but stumbled across the schematic over on FSB. Apparently it's another Marshall-in-a-box type. Sounds pretty good. Should fit nicely in a 1590B. The 1uF and 2.2uF caps are tantalum in the original but eletrolytics could be used as well. Original 1S1588 clipping diodes could easily be replaced with 1N4148s if need be.

MOSFET Pie

Stumbled across this Big Muff variation designed by Anders over on the Tagboard forum. Seemed like a cool design for Fuzz Friday. Here's what he had to say about it:

Inspired by Skreddy Top Fuel and a DIY muff project One Knob Gilmour I have been tinkering with a big muff circuit using mosfet transistors for all four gain stages along with mosfets wired as diodes in the second clipping stage. I've been using 2N7000's just because I have tons of them but other mosfets like BS170 should work as well. For more variety I added AMZ big muff tonestack. 

Sounds tighter than a regular muff and has more distortion elements than fuzz. If any fancy building this shielded wires is a must since the gain is pretty high and it's on the edge of oscillation when pots is dimed. 

Coupling cap values is mostly from Violet Rams Head muffs to give a balanced tone but those could be tweaked to desired values as well as the small BC caps. 

Craig Anderton Tremolo

To say Craig Anderton's body of work is vast is probably an understatement. But within that body are several DIY classics, and this tremolo is no exception. This is a modified/updated version, specifically in the power section with a +/- 9v charge pump. The vactrol in the original is VTL5C1, but some combination of home rolled LDR/LED combo will probably work (you'll just have to experiment a bit). Schematic here. It'll be snug, but it should fit in a 1590B.

Greer Amps Lightspeed

Wondered about this one for a while (but always suspected it was YATS). The best way to describe the Lightspeed (that I can think of anyway) is it's kind of like a Timmy with the bass and treble controls fixed and a simple treble cut tone control added just before the volume pot. The most interesting thing with this is the clipping, with 5 diodes in asymmetrical orientation (3 going one way, 2 going the other). Should fit in a 1590B or 125B nicely with board mounted pots.

EHX Bassballs

Not sure I missed doing this one ages ago, but better late than never. The Bassballs is a classic envelope filter that's been a staple of Electro Harmonix's line up for a long time. Designed for bass, but works great on guitar as well. Trimmers are very dynamic and might be fun as external pots. Also if it's super loud, adding a volume pot at the output is super easy—remove the 47k resistor off the Out pad, wire the Out pad to lug 3 of an A100k pot, lug 1 to ground, and lug 2 becomes the new circuit output. Here's the schematic for reference. Should fit in a 1590B, though it'll be a tight squeeze.