Run Off Groove Condor Cab Sim

Part of the last request included a cab simulator to run the headphone amp through. The ROG Condor is a great cab sim and has a fairly low parts count. It uses a JFET amplifier at the input, boosting the signal to drive the following 3 filters (Bridged-T notch filter, High-pass filter, and Low-pass filter). Much more info on the circuit can be found here, as well as a few mods. J201 apparently sounds the best for Q1, but similar DSG pinout JFETs will also work. Any dual opamps can be used for the 2 ICs, so socket and try the usual candidates (TL072, JRC4558, etc).

Run Off Groove Ruby

Got a request for a headphone amp, "for those of us who hit their peak inspiration when everyone's asleep." Being guilty myself of waking up my 1 year old son with a Peavey Classic 50 with the volume only at 2, I thought this was an excellent idea. So here's ROG's Ruby–a 386-based amplifier that can easily fit in a 1590A, or even an Altoids tin. Check out the ROG article on the circuit for more info and a couple of mods.

Rotary Capacitor Switch

The input caps on some old circuits like the Fuzz Face, Tone Bender, or Rangemaster are ripe for variation. Here's a board that will allow you to switch between 6 different capacitors of your choice. You could also use this for a Gibson Varitone-like switch on a guitar. As with the Rotary Clipping Switch layout, use a 26mm enclosed 2 pole 6 position PC mount rotary switch (preferably from Alpha as their datasheet is what I used to layout the switch pads), mounted from the component side.

Rotary Clipping Switch

Ever want to have as many clipping options as possible on a distortion or overdrive pedal? Here's a way to add up to 6 different combinations of diodes, LEDs or Mosfets with a 6-way rotary switch. Here's the break down on the different diode layouts by switch position:

1. Standard 2 diode orientation
2. Asymmetrical diode orientation
3. Diodes in series 
4. Mosfets
5. Asymmetrical LED orientation
6. Standard 2 LED orientation

You can always omit components from one of the switch positions to have a clipping bypass mode. You can also use jumpers or angle diodes if you don't want series or asymmetrical diodes. Use a 26mm enclosed 2 pole-6 position PC mount rotary switch (preferably from Alpha as their datasheet is what I used to layout the switch pads) and mount it on the component side.

Vox Treble Booster

The Vox Treble Booster was a simple silicon treble boost effect that plugged straight into an amp's input jack. It allowed the user a boost in high frequencies for lead work. I laid this one out to use as a built in effect on a guitar (hence the lack of a power filtering cap and polarity protection). Note that the 10uF cap is on its side to reduce the height of the populated board. It should easily fit in a 1590A. If you want a volume control use a 100k pot with the Out pad going to lug 3. Lug 2 becomes the Out and lug 1 goes to ground. I found that I really didn't need a volume pot though, as the effect level was right around unity.

JHS Morning Glory

The JHS Morning Glory is a modified Blues Breaker overdrive, but with an added JFET output buffer to increase the volume. The original Marshall circuits barely made it above unity with the volume maxed (see the video below), so the output buffer is a good improvement over the original. There's also a high cut switch to help tame single coils a bit. I wasn't quite able to get the on-board pots to be in the exact layout as the JHS units (the Tone control and High Cut switch are reversed), but it's close enough. You should be able to board mount the SPST high cut switch as well.

Greer Amps Ghetto Stomp

Here's another one of Nick Greer's offerings. Like Sean over at Lovepedal, he seems to be getting a lot of mileage out of the Electra circuit. I've laid this out for on-board pots with the board mounted vertically like this:

Photo by Bob Scott/negatron.org

I saw on the Greer Amps website that a special version of this was made with a BC107 transistor, so use that if you want to replicate the blue version of this pedal.