Ibanez OD-850/Maxon D&S OD-801

There are a host of Big Muff clones and variation, but one of the most sought after clones is the Ibanez OD-850. Like all vintage Ibanez pedals, the OD-850 is just a rehoused and rebadged Maxon design–in this case, the D&S OD-801. While this shares a lot in common with a Ram's Head BMP, it differs greatly in the tone section. Here's Kit Rae's description:

Maxon opted to alter the tone stack for this clone, fixing the bass value across the tone pot sweep... The whole high pass and low pass tone section is incorporated into the recovery stage. What this did was to make the bass and treble sides have a more useful range of sounds. The treble side retains some bass across the sweep, so it is not as ear piercing and trebly as a standard BMP when dialed completely to the treble side, nor do the highs seem to be completely removed when dialed fully to the bass side. It kind of makes finding the 'sweet spot' a bit different sounding than the traditional BMP tone stack, but that is what makes this version unique.

I've laid this out for more common CBE pinout transistors, where as the C828s of the originals are BCE. This follows the first version released in 1974, and will fit in a 1590B with board mounted pots. Here's the schematic for reference.

Toadworks Mr. Squishy

Here's an interesting take on the Orange Squeezer compressor from Toadworks. Extra controls and clean boost capabilities when the Squish control is at zero and the Level control is maxed. Schematic here for reference.

Jon Patton Cardinal Tremolo V2

The Cardinal Trem is a harmonic tremolo designed by Jon Patton and meant to emulate the tremolo effect built into several Fender amps from the early 60s (Twin, Super, Pro, Showman, etc). What makes it harmonic? The audio signal is amplified by the first JFET stage, then split into a high-pass path and a low-pass path. Each path is modulated optically with the vactrols, then amplified and mixed into the output. The LFO is designed around a quad opamp (in the original it's a quad, I had to divide it into 2, dual opamps to make it fit) and pulses the LEDs in the vactrols. Schematic and full circuit explanation can be found here.

The L pad will need to be grounded in some fashion for the LEDs to pulse. LED1 can be used as an external rate indicator, either on all the time or as the on/off indicator as well. Jon recommends using optical bypass for this effect (hence doing the Optical Bypass layout on Tuesday 😁), so to use LED1 as the indicator LED, connect it to both pads for the LED on the Optical Bypass board and ground the L pad. If using a 3PDT, just connect the L pad to lug 4 and lug 5 to ground as outlined in the General Layout Notes page.

Optical Bypass

Here's another alternative to the 3PDT for bypass wiring. It's based on the method VooDoo Lab uses for bypass and uses a optocoupler to achieve true bypass using a DPDT. I've drawn up 2 different layouts for this: a standard perf/PCB layout, as well as another PCB I did in Eagle with the footswitch board mounted. There are extra pads so the compact or the larger DPDT footswitch can be used, as well as an extra pad for the resistor so 1/8th or 1/4th watt can be used.

Note, in the board mounted footswitch version In/Out pads refer to the jacks, and Send/Return refer to the effect in/out.

EarthQuaker Devices Dirt Transmitter

To close out EarthQuaker week, here's the Dirt Transmitter. I traced this one myself and below is a video showing the process. It's similar to a Fuzz Face, but a little different. I found this description from (I'm assuming) Jamie over on TGP:

I guess it's kinda like a fuzz face but it started as two gain stages running into each other with an input gain control and a sag on the second stage (bias). Voltage feedback was added and it became similar to a fuzz face in topology but it sounds nothing like one IMO. In this case the sound is totally dependent on the transistors, replace them and it's a whole different beast.

Here's my video on tracing the circuit as well as a demo:

   

Here's the schematic:

And the layout:

You can also order a few boards from OshPark here.

Update:

Added a perf layout for this based off the Eagle board above.

EarthQuaker Devices Dunes

If the Palisades is too much for you, the Dunes has a much smaller footprint and less controls to get distracted with. Pretty standard Tube Screamer clone with clipping options and a couple tone shaping switches. Might be a bit of a squeeze but it will fit in a 1590B with board mounted pots.

EarthQuaker Devices Crimson Drive (3-knob)

What? A Monday post? Yep. This week is EarthQuaker week. EQD is easily my favorite pedal company, and I own more of their pedals than any other builder. Not to mention I've learned a lot about pedal design from Jamie's work. So this week I'll be posting 3 EQD circuits and hopefully a video to go along with this week's Fuzz Friday.

To kick EarthQuaker week off, here's the now discontinued Crimson Drive. Did the 2-knob version ages ago, but the 3-knob version was recently posted on FSB so I gave it an update. Beyond the addition of the tone control, there's a few capacitors removed compared to the 2-knob version. The germanium transistor is also different–an NPN instead of the PNP–and the germanium transistors were swapped from 1N60Ps to 1N34As. Easy fit in a 1590B with board mounted pots.