SoulSonic FX Hunny Bunny

Here's another design by Martin from Soul Sonic FX. Here's what he had to say about it over on FreeStompboxes:

It's a cool little hybrid combo of an opamp driving a MOSFET. It has a great range of drive, from light and crunchy to thick and heavy. At it's highest settings, some people might consider it a distortion, I guess it just depends on how hot your pickups are. You can see some fun tricks used in this circuit; subtle things that give it the special charm it has. 

Electro Harmonix Muff Fuzzes

Around the same time that the EHX Big Muff was first released in 1969, Mike Matthews also released the Muff Fuzz. It was unrelated to the BMP other than the name, and came in the same small enclosure as the LPB-1 that plugged straight into the guitar. Later it was re-released in a floor pedal as the Little Muff Pi and more recently as the Muff Overdrive. In the mid-70s, the circuit was updated, moving away from the Fuzz Face based transistor circuit to a design based around the popular JRC4558 op-amp. I've laid out both versions below and both should fit in a 1590a.

Mad Professor Sky Blue Overdrive

Here's another BJF designed circuit: the Sky Blue Overdrive. There are 4 controls: Z adjusts input impedance, Distort. controls gain, Texture adjusts the hard clipping, and finally the Volume. It uses 3mm LEDs in the feedback loop of the opamp, and then JFETs for hard clipping.

Catalinbread Katzenkönig

Here's a new one from Catalinbread for #fuzzfriday. The Katzenkönig–the cat king for those of you who don't sprechen sie Deutsch–is a silicon tonebender-type fuzz with some RAT features thrown in. Catalinbread was kind enough to publish the schematic in the manual for this effect. Pots can all be board mounted using right angle PCB pots mounted from the solder-side of the board. The exact transistors used in this effects weren't published in the manual schematic, but lower gain NPN silicons should do the trick. Socket and experiment with your favorites.

Edit Oct. 14: Original transistors are BC550B, in the 300-400 hfe range. 2N3904s will work well also.

Lovepedal Englishman

Here's the Lovepedal Englishman. It's claimed to sound like a cranked Vox (either AC15 or AC30 depending on which clipping diodes are selected). Like many of Lovepedal's offerings, this circuit is built around a single transistor. Unlike many of Lovepedal's offerings, it's not based off the Electra Distortion. Instead, it draws from the EHX LPB-1 booster with switchable diodes at the output.

BearFoot FX Sea Blue EQ

Here's a cool EQ/booster from Bjorn Juhl. If pushed hard, it will break up much like a tube EQ would, and adds warmth and clarity to your tone. It uses 2 JFETs and a James style tone stack.

SoulSonic FX Stage Overdrive

Here's a cool overdrive circuit designed by Martin from SoulSonic FX. It's said to be a "Klon Killer," so if you've been disappointed by that circuit, give this one a go. Signal goes through a buffer then is split between clean out put and the rest of the effect. So not a true-bypass effect, but having a buffer in your signal chain won't kill you. And the buffer on this thing is really top notch. For switching use one side of a DPDT for the effect, and the other for the LED indicator. For more info and the schematic, check out the thread on FSB.

Devi Ever Electric Brown

Here's a unique little circuit from Devi. Plenty of gain on tap to go from just a boost, to an overdrive, to fuzzy the more your turn up the volume control. The Pregain control acts more like a tone control, panning between 2 capacitors. The first transistor stage is kind of like an Electra Distortion, and then I don't quite understand the 2nd transistor, but it works and it sounds good.

Fulltone 70

For #fuzzfriday, here's the Fulltone 70 fuzz. Like the Fulltone 69, the 70 is a tweaked Fuzz Face circuit, following the silicon version. Like the original silicon Fuzz Face it uses BC108 transistors, though others can be used. Q2 should be higher gain than Q1. One of the nice things about the 70 is the added Mids control, which adjusts the some of the voltage reaching Q2 and the output capacitor. You can board mount the pots using right angle PCB mount types from the solder side.

BearFoot FX Pale Green Compressor

Here's another great circuit by Bjorn (who also designs all the Mad Professor stuff). It's an optical compressor that's very similar to the Mad Professor Forrest Green Compressor. It's not too heavy handed, and is, as Bjorn has said, "The compressor for people who hate compressors."

Angry Beard III

Here's another circuit I ran across will going through the Free Information Society site. It's designed by Jamie Heilman and seems to be like if a Distortion + and a germanium fuzz had a baby. The first stage uses a single op-amp (NE5534 in the original, but others could be used–TL071, LM741, etc) that pushes as single PNP germanium transistor. The orientation of that transistor confuses me and makes me wonder if it should be an NPN, or a PNP flipped 180º. Here's the schematic so you can share in my confusion. So socket the transistor and experiment. I've added the small capacitor in the feedback loop referenced in the schematic notes. Add it if you have some extra noise. This one should easily fit in 1590a.

I don't have a demo of this circuit, but I thought people might get a kick out of how I layout these circuit boards. It's not really a tutorial, but you can get a feel for how I make my layouts. I use DIYLC and then Photoshop.

A Small Personal Update

Just wanted to give you guys a heads up: If I don't post as frequently as I usually do, or don't respond to comments, it's not because I don't love you guys anymore. ;) My wife and I just had our second son today and I will probably be continually exhausted for the foreseeable future. In all seriousness, I'm super excited about this addition to my family. I'll still try and post as much as I can, and I have a bunch of layouts saved up for this "life event," so there shouldn't be any long silent periods. 

Anyway, mommy and baby are doing well, and I'm gonna go try and be a helpful hubby/daddy.

ColorSound Bass Fuzz

Here is the ColorSound Bass Fuzz for today's #fuzzfriday post. It's pretty much an amputated Big Muff. It's been tuned for bass guitar and has the gain recovery stage removed (for simplicity I suppose... that and the BMP can be just excessively loud). The first gain stage also doesn't have the typical diodes a normal BMP has.

Blue Magic

Here's an overdrive I stumbled across while browsing the Free Information Society site. It was designed by Jake Nagy and was quite popular in the DIY world at while back. Here's what he had to say about it:

Blue Magic is a very low to medium grit, tube-like, overdrive pedal that is based on a MOSFET (BS170) pushing a JFET (J201) into distortion. Voltage at the JFET drain should be about 4.7, but tune by ear. [The 22k resistor] smooths out the sound, but at the cost of sounding less “open.” Thus, reduce [it] for a more open sound. Also, experiment with the coupling caps and the source bypass caps.

I've increased the power filter cap and added polarity protection. You can board mount pots using right angle PCB mount pots from the solder-side of the board.

Run Off Groove Eighteen

The ROG Eighteen is an overdrive/distortion circuit based on the classic 18watt Marshall amp of the late 60s. It uses JFETs in place of tubes, like many other ROG amp-based drive effects. J201s are specified, but socket and try some other JFETs (2N5457, MPF102, etc.) The Volume control will probably act more like a gain control, though there is no resistor limiting the minimum amount of signal sent to ground when it's at zero. For the schematic and more info on the circuit see the ROG article.

EMMA ReezaFRATzitz

The ReezaFRATzitz is a high gain overdrive/distortion circuit based around a CMOS chip, most likely a CD4069N or 74HCU04. This layout reflects a modded version by FreeStompboxes member thn.technik with added Bass and Mids controls. Here's a link to his schematic and build pics. You might be able to squeeze it into 1590B, but you'd probably be more comfortable in a 1590BB. This is not originally a true-bypass effect. As you can see in the layout drawing, there is a "Clean Out" and a regular, or "Effect Out." The signal comes in from the input jack directly to the board and into the buffer. From there a DPDT footswitch switches between the Clean Out and Effect Out. If you prefer true-byass, you can ignore the Clean Out pad and just wire this like you normally would. You can then eliminate the 150n cap and 470k resistor from the Clean Out pad. Here's a demo of the original:

Mona Lisa Overdrive

Here's a light-medium gain overdrive designed by RNFR from the Apocalypse Audio blog. Here's what he had to say about it:

I thought I would build something that would turn on the guys that were into the lighter side of things- something different than my usual wall of fuzz tones.  With the MLOD, you can get a heavy boost, or a light overdrive reminiscent of vintage microphone preamps.  The fancy thing about this circuit is the lack of coupling caps in the audio path- something usually reserved for mic pres and hifi circuits.  This lends itself to the "transparent",  uncolored sound happening here.  If you encounter any oscillation at the highest gain settings, simply raise the value of the 100 ohm resistor near the gain control to lower the amount of maximum gain. 


Use sockets for the transistors. I'd start with J201s or 2N5457s for Q1 and Q4, and 2N2222 or 2N3904 for Q2 and 2N2907 or 2N3906 for Q3.

WEM Pep Box

Here's a cool vintage fuzz circuit from the mid 60s–the WEM Pep Box. It's probably best known its use by John Lennon during the Revolver sessions. There are two versions of this effect, the first using germanium transistors and the later using silicon. I've drawn up layouts for both iterations of the circuit, as there are slight variations between the two. The originals used a 500k Level pot with a 56k resistor in parallel. This equates to a 50k pot, so the layouts reflect that. Also, if the effect is to thick for your tastes, try reducing the 2 electro caps down to 10µ. It seems both values were used.

If you're building the germanium version, the layout shows positive ground on the perf side (original transistors were PNP), and the PCB side shows negative ground (for use with NPN germaniums). Since the original ACY41 transistors are pretty scarce now (especially outside the UK), socket and experiment.

Here's a demo of the germanium reissue:

And a demo of an original silicon unit:

Emerson Customs EM-Drive

Here's a really simple "transparent overdrive" circuit that was a must have a couple years ago. People compared it to the Klon and Timmy drives. Originals use paper in oil caps, which some claim sound better than modern film or ceramic caps. That's a debate for another time though. I've drawn it up so you can use big mojo caps, or with more common caps for a much smaller footprint. Both versions have a couple tweaks. In the mojo layout, I've added a pull down resistor after the gain pot to try and eliminate footswitch pop. In the smaller layout, I've added some optional clipping diodes (which I think really improve the sound of this thing), and power filtering and polarity protection.

Shin Ei OB-28 Octave Box

Here's a weird one for you–the Shin Ei Octave Box. It's apparently an all analog clean octave down effect. I'm not going to pretend to understand how it works, but there are a lot of transistors. Originals used 2SC644 and 2SC666 transistors, which I think were in the massive TO-3 package. I've drawn the layout for more modern replacements, BC547s and a BC557. Other transistors like the 2N3904/06 or 2N5088/87 would probably work as well. Socket and experiment with what you have on hand.

King Dubby Delay

Here's a cool delay designed by Nocentelli posted over on FSB. Here's what he had to say about it over there:

Here's a variation on the deep blue delay; two PT2399 chips and a current mirror delay pot give around 2200ms delay, although beyond 700ms gets pretty lo-fi. There are two points where a momentary SPST can be used: Either to briefly connect the input to the delay input on select phrases (dub mode), or to bypass the repeats feedback resistor for self-oscillation on demand.

Note: I've recently found out the capacitor going from Repeat 3 to Osc Sw2 is 22n.