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Wednesday, December 31, 2014

DOD FX55 Distortion (2-knob version)

Last post of 2014. Happy New Year, everybody!

Here's the early 80s DOD FX55 Distortion, without the original switching circuit so you can wire it for true bypass. The original used a TL062 dual op-amp, but the 2nd half of it wasn't in the signal path all, so I went with the single TL061. The off-board wiring pads aren't as neat as I'd like, but I wanted it to fit in a 1590a.


You could fairly easily use this same layout to make the DOD FX50 overdrive with the following mods:

• Change the 1k resistor to 4.7k
• Change the 3.9M resistor to 1M
• Place a 1n capacitor between lugs 1 and 3 on the Level pot

Tuesday, December 30, 2014

Lovepedal Black Magic

Haven't done a layout with board mounted pots in a while, so here's the Lovepedal Black Magic. It's a LM386 based distortion that tries to get achieve the "Brown Sound." I added polarity protection and put the LED resistor on the board as well.


Friday, December 19, 2014

Run Off Groove Modified EA Tremolo

Here's Run of Groove's take on the DIY classic EA Tremolo. I've laid it out so that the rate indicator LED can also be used as the on/off indicator.



Here's how you'd wire the LED to a 3PDT switch as the on/off indicator.



Thursday, December 18, 2014

MXR Phase 45

I've seen a lot of different PCB layouts online for this effect, but all of them had at least one jumper on the board. Jumpers aren't the end of the world, but I know for me, if I'm going to go to all the trouble of etching a PCB, I don't want to mess with jumpers. This layout is jumper-free and will still fit in a 1590B type enclosure.

MXR released the Phase 45 along side the more famous Phase 90 in 1975. The name comes from the number of degrees of the phase shift it's capable of. Some say it's similar in sound to a UniVibe and can be modded into being more of a vibe pedal.

The original units used 2N5952 for the FETs (make sure you match them by the way), but others can be used. I listed 2N5457 in the layout because they're what I have on hand. MPF102, J201, or 2N5458s could also be used. Really, any FET with the DSG pinout.




If you want, you can hardwire the C500k pot to the top of the board, though I would suggest using a long leg PCB mount pot (like these) and mounting it above the component side of the board (like this).




Tuesday, December 16, 2014

Dan Armstrong Orange Squeezer

The Dan Armstrong Orange Squeezer compressor has become a staple among the DIY community. Original units plugged straight into the guitar, with no external controls except for an on/off switch. This layout has the level control offboard, but the bias is a 10k trimpot, but could easily be wired offboard as well. And you should be able to squeeze it into a 1590A. (See what I did there? :D)

Edit:

Here are a few mods if you want to use it on bass. Some say stock is best, others say to uses these substitutions. As always, YMMV.

• Swap the output cap from 4.7µ to 1µ (between the 390k and 1.5k resistors, below the IC)
• Swap bleeder cap from 4.7µ to 10µ (cap connected to the 1N34 diode)
• Reduce the feedback resistor from 220k to 200k (between Q2 and the IC)

Wampler Plexi-Drive

Here's Wampler's Plexi-Drive, another Marshall-in-a-box pedal. The original unit uses a 470µ capacitor for power filtering, which seems like overkill to me. I've replaced that with a 100µ cap that should do the job just fine.

Some build reports on FSB say that the 15k resistors from 9V to the drains of the J201s might need to be tweaked to bias the JFETs correctly (4.5v), so either socket those positions or use trimpots. Also, if the tone control is too dark sounding for your taste, replace that A25k pot with an A500k to brighten things up.




Monday, December 15, 2014

Ramble FX Marvel Drive (version 1)

One of the many Plexi-in-a-pedal options out there, the Marvel Drive has parallel input stages allowing you to create your own blend between the normal "channel" and the treble "channel." Gearmandude can show you better than I can try to explain it:




Friday, December 12, 2014

Basic Audio Scarab Deluxe

This is a variation of the Mictester Silicon Tonebender, which is based of the Tone Bender Mk II Professional circuit. John Lyons was kind enough to shed some light on his version over at FSB.



Earthquaker Devices Crimson Drive (2-knob version)

Here's a good sounding overdrive from Earthquaker Devices. This is for the first incarnation of the Crimson Drive with just level and gain controls. Uses a J201 in a buffer stage and a PNP AC128 in the gain stage.



Dirk_Hendrik from FSB traced one and drew this schematic.


The power filter section makes me scratch my head a bit, as it uses 2, 100µ caps. To keep things a little simpler on the board I just put one 220µ cap, since the equivalent capacitance of two parallel capacitors is the sum of the individual capacitances.

Also note that the schematic calls for a low current LED, hence the 10k resistor from the power supply. Change that resistor to around 2.2k if you're using a more common LED.


Tuesday, December 9, 2014

Simple Transistor Compressor

FSB member Mictester came up with this design a couple years ago. Utilizes 4 transistors, 1 PNP and 3 NPN, though you could probably use an NPN in place of the PNP. Best to socket and try a few different transistors. The schematic says BC213L for Q1 and BC183L for Q2-4, but any medium gain transistors should work okay (2N2222, 2N2907, 2N3904, 2N3906). I added some of the mods suggested in the FSB thread for higher input impedance and noise reduction.


Rockett WTF

Mmolteratx traced this one over on FSB. Figured I'd put it up. Seems to be a BossTone derivative with some tweaks. Here's the original:


And since all the offboard wiring is making a few people say, "WTF," here's the rat's nest that is the offboard wiring for this effect. The "In" and "Out" wires go to the normal 3PDT switch you'd use for effect on/off.



Monday, December 8, 2014

Electro Harmonix Ram's Head Big Muff

There are a lot of versions and subversions of the Big Muff. Many consider the Violet Ram's Head to be the best, though many consider the Triangle, or IC, or Green Russian, etc. the best. YMMV

This one has the pots hard mounted to the board, though depending on the enclosure you use, it may be best to wire them off-board. This layout is heavily inspired by the original Ram's Head circuit board, just resized for more typical sized components. I've also added a polarity protection diode, power filtering cap, and an LED resistor.


EHX also used this same circuit for the Guild Foxey Lady (3-knob) as well as several other OEM pedals EHX produced. 

Friday, December 5, 2014

Zvex Wooly Mammoth

The Zvex Wooly Mammoth is a Fuzz Face derivative designed for bass, but sounds awesome on guitar as well. For this one I've laid it out for on board pots oriented like the originals. On the PCB I added an LED and LED resistor for on/off indication. As with my layout for the Fuzz Factory, this layout is designed for the pots to be mounted on the component side of the board.


Wednesday, December 3, 2014

ProCo RAT ('86 version)

Since I did the Blower Box yesterday, and it's essentially a RAT, I figured it wouldn't take too much effort to convert that layout to the original. So here's the original '86 RAT.


Tuesday, December 2, 2014

Idiot Box Effects Blower Box

Here's a pretty cool bass distortion based on the RAT. The normal filter section on a RAT is replaced with a passive baxandall network. It was traced by FSB member p.eat and the schematic I based this layout from was drawn by johnk.





Run Off Groove Odie

Here's the Odie from Run Off Groove. It's an alternative to the Tube Screamer using JFETs. Be sure to adjust the drain trimpots to 1/2 the supply voltage. Sound clips can be found here.


This one is verified (and sounds fantastic). Here's a few pics of my build.





Monday, December 1, 2014

Univox SuperFuzz (stock)

Here's a layout for the stock Univox SuperFuzz. I probably should have drawn this one first and then the modded one below, but it was actually easier to take the modded layout and reverse it back to stock.