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.

Fredric Effects Unpleasant Companion

While we're on the subject of the Companion Fuzz, here's an adaption by British pedal company Fredric Effects. It replaces the fixed tone stack of the original FY-2 with a Big Muff tone stack, and adds a LPB-1 booster after the volume pot to increase the volume.

Shin Ei FY-2 Companion Fuzz

The epitome of buzzsaw fuzz tones, the Shin Ei Companion Fuzz has become a highly sought after fuzz box. The one drawback to the FY-2 is the tone stack between the Fuzz and Volume controls. Besides not being controllable, it drops the volume of the effect below unity. I've drawn up a stock layout, as well as a modded version with a booster at the output to up the volume to a more reasonable level (based on the schematic from General Guitar Gadgets). The stock layout will fit in a 1590A, and the boosted version could as well, it would just be a tighter fit.

A useful mod to the stock layout could be adding a tone bypass switch. Use a DPDT (on/on) and wire it like this:

When the tone stack is bypassed, the volume should increase significantly. 

Run Off Groove Phozer V1

I came across the schematic for this while looking through RunOffGroove.com. It's an interesting mashup of Tim Escobedo's Idiot Wah and the LFO section from the EA Tremolo to produce a faux phaser effect, and apparently works very well at higher speeds.

Lovepedal/Hermida Audio Zendrive

Got a request for this one. The Zendrive is a low-to-medium gain overdrive, delivering blues to jazz tones. It has an interesting clipping section, using a combination of diodes and MOSFETs in an asymmetrical arrangement. I've drawn the layout to accommodate board mounted pots (from the solder-side) and it will fit easily in a 1590b.

Simple JFET Buffer

Here's a simple one for your Saturday. As the name implies, this is a simple buffer based around a JFET transistor. This layout follows the schematic from Jack Orman's great article on Basic Buffers. Thought this would be useful if you want to add an input buffer to an existing pedal or to a project that doesn't have one.

DOD Studio BiFET Preamp 410

The original DOD units had "balanced" XLR output as well as the normal 1/4" jack and no footswitch. This has been adapted for stompbox use and could work well with acoustic guitar.

Electro Harmonics Pulsar Tremolo

Here's the original EHX Pulsar trem from the 70s (not to be confused with the modern Stereo Pulsar EHX manufactures today). It features Intensity and Speed controls as well as a switch to go between a hard and soft wavefrom. Original units often suffer from clock bleed from the LFO section. So I've drawn a second layout with mods to try and fix it. The 470Ω resistor above the IC and the 47µ cap below Q1 should be tweaked to find the values that work the best. Pots can be board mounted from the solder-side using right angle PCB pots.

Ross Distortion

The Ross Distortion is very similar to two other famous distortion boxes of the late 70s (MXR Distortion +, DOD 250). However, it uses one side of a 4558 dual opamp instead of the single opamp (741) found in the the other two, and a few other tweaks in component values. There are two versions of this circuit: the Tan version, which uses 2 germanium diodes for clipping (originals used 1N270s, but 1N60Ps or 1N34As should also work just fine), and the Black version, which uses 3 silicon diodes for asymmetrical clipping. I've drawn up 2 layouts for each version, both will fit in a 1590A. The only difference is improved power filtering and added polarity protection in the larger layouts. The yellow 1µ caps are tantalum.

Maxon OD808

Maxon released the OD808 in 1979 and it generates natural, mild overdrive tones and is similar to the TS808. Original units used MC1458P ICs, but I've listed JRC4558s as they're likely to be on hand for many of you. Also the original diodes were Panasonic MA150. I've listed 1N4148s as a replacement, but socket and experiment there. I've read of people using 1N60Ps or similar germanium diodes to give it an even more tube-like sound.

Oz Compressor

Here's an interesting LM386-based compressor designed by Brett Robinson (DIYSB member Toney). I found the schematic for this while searching for something else. Apparently there are various incarnations (and names too) of this circuit, but this seems to be the most popular version. Should fit easily in a 1590A, though, I'm not sure about board-mounting the pots. You might have to get creative there...

VooDoo Lab Sparkle Drive

The Sparkle Drive is a very versatile drive pedal, offering everything from clean boost to full on dirty Tube Screamer tones. The Clean blend allows you to layer both clean and dirty sounds (kind of like playing through two amps, one clean and the other dirty). One of these has lived on my pedal board for the last 4 years and it sounds great for both guitar and bass.

A common mod to this circuit is adding some clipping options. On the PCB I've added 2 extra pads right above the "Gain 2, Gain 3" pads. These will allow you to use an on/off/on DPDT switch to go between which ever diode combination you want. The most common combination seems to be the stock 1N4148s and red LEDs. The center "off" position of the switch will remove the diodes altogether. See lvlark's vero layout for the switch diagram. 

VooDoo Lab Overdrive

Often forgotten and overshadowed by one of it's derivatives, the VooDoo Lab Overdrive is the basis of the famous Fulltone OCD. The main differences between the 2 circuits is the clipping (OCD uses 2 Mosfets) and the added tone control of the OCD.

On an somewhat unrelated note, I've had a lot of people having issues with printing transfers from the site. It seems Blogger resizes images sometimes when they're embedded in a blog post. So I've created a library with every PCB transfer already scaled and in PDF format. To access this library, just go to the top of the page and click on the "Transfer Image Library" tab. All you should have to do is download and print out of Adobe Reader. If for some reason a transfer image doesn't print correctly, I've also included the dimensions of the board in the PDF so resizing can be done if need be. Hopefully this will help alleviate any headaches resulting from trying to print transfer images. Happy etching.

Maxon OD880 Soft Distortion Overdrive

The Maxon Company is probably most famous for manufacturing the legendary Ibanez Tube Screamer pedals (among many other Ibanez offerings). Because of this (and especially in non-Asian markets) Maxon pedals were often overshadowed by their Ibanez-branded brothers. But throughout the company's history, they have produced a great offering of effects.

The Maxon OD880 Soft Distortion Overdrive was first produced in the mid 70s, and originals are very rare, especially in the West. It used 3 ICs (741 types) to produce a great transparent overdrive effect. The pedal was reissued in the 90s exclusively in Japan with an updated circuit that used 2 opamps. The layout below is for the original 3 IC version. I've added power filtering and polarity protection. It should fit just fine in a 1590B.

Walrus Audio Deep Six Compressor

The Walrus Audio Deep Six is a versatile compressor that gives studio level compression in stompbox form (that's what their website says, anyway). It's very similar to the BYOC 5-knob compressor, with the only difference being a few component changes in the blend and output stages. I set out to try and make a layout that would fit in a 1590B with on-board pots. Let's just say there's a reason most circuit boards today are at least double-sided. You could board-mount the Ratio and Level controls if you want (use right angle PCB pots mounted on the solder side) and in theory it should fit in a 1590B, but if it were me, I'd put it in a 1590BB and give myself some elbow room. Most 1µ caps are laid out for tantalums to save space and reduce noise.

Here's the schematic I drew for reference.

Crowther Audio '77 Hot Cake

A lot of awesome things came out in 1977: the op amp version of the Big Muff, the grey box DOD250, Fleetwood Mac's Rumours, the Sex Pistol's Never Mind the Bullocks, and STAR WARS (May the 4th be with you). The Crowther Audio Hot Cake also made it's debut in 1977, and you could say it was one of the first "boutique" stompboxes ever made. It featured an 741-type IC and a unique way of bypass switching. To quote Steve (bajaman) from FSB:

It used a 120k resistor and simple shorting switch from the bottom of the drive pot, 1k, 470p, 12n, 12n, and bottom of the level pot, to earth. When the switch is open all the foregoing components were lifted by the 120k resitor - hey presto bypass mode. When the switch is closed: bingo, tons of boost.

To add an LED on/off indicator, I would suggest using a DPDT switch. One side can be used to bypass the effect, and the other side for the LED. 

As many know, an updated version of the Hot Cake was released in 2003. This has a presences control instead of the mids lift/normal switch in the original, and has a more Fender-like sound compared to the Marshall-like sound of the original. Many say that as you turn the drive control up, the tone gets muddy, but with the volume cranked and lower drive settings, the Hot Cake really shines. I've added a polarity protection diode, a power filtering cap, and a resistor for the LED on the board. For more info, check out the FSB summary page. I've also created a fabricated board for this circuit in the store—the Crempog.

Jack Deville Vintage Two-Knob Fuzz

I've been wanting to do a Fuzz Face with on-board pots for a while, and when I stumbled across a schematic of Jack Deville's (Mr. Black) take on the classic circuit, things just fell into place. This uses NPN germanium transistors (though you could use silicons if you must), and I tried to leave plenty of room for them if you're using some of the big Russian germaniums easily available off eBay (GT404, MP38, etc). You could build a standard Fuzz Face on this board, just mind the component changes and replace the resistor from Fuzz 1 to ground with a jumper.

Update 5/4/15:

Verified this last night. Here's a pic of my build.

Used some Russian мп38 germanium transistors (Q1: 80 hfe Q2: 110 hfe) and a 7.5k resistor in place of the 10k trimmer (ran out of those). For the input cap I tried out a couple different values (47n, 100n, 220n...) but settled on 39n, as it seemed to give more clarity that higher values. Socket and experiment.