Big Muff Clone - Coda Effects Dolmen Fuzz Pedal

When I started doing research on which guitar pedals I wanted to build, the Electro Harmonix Big Muff may have the largest following of any pedal. Nearly every boutique pedal provider has a version of the Big Muff, and there are many forum posts arguing which Big Muff configuration is the best of the best.

After much digging, I found an extremely well documented PCB which can be configured to many different versions including the V1 Triangle, V2 Rams Head, V2 Ram's Head Violet Era, V3 Big Muff, Green Russian, or Civil War w/power booster... you can even tweak it to work similarly to the Black Arts Pharaoh... so lots of headroom to try different things. Best of all, the PCB is only $8, so you can experiment away on the cheap. Speaking of cheap, I highly recommend Tayda electronics, you can get most of what you need for a fraction of the price that Mouser or Digikey would charge. All the resistors, switches, op-amps, sockets, etc. I've purchased there work perfectly well. I do usually splurge on name-brand electrolytic caps from Mouser (e.g. Nichicon or Panasonic), but for everything else, Tayda has you covered.

Coda Effects Dolmen Fuzz on right

If you want to be cool, you'll get a nicely powdercoated enclosure for your Big Muff clone from Mammoth Electronics... or paint your own :) I chose a translucent blue powdercoat for this pedal. The documentation at Coda (PDF) has a printable template for your drill holes. Make sure to not resize the document when printing, otherwise you might have to order another chassis when your drill holes don't line up.

Using Coda's drill template makes things a snap

Adding the holes on the drill press

So purdy!

Now it's the fun part (at least for me), populating the PCB with parts. As you know, start with the small parts first (usually the resistors) and work your way up to the capacitors. I'm pretty OCD about this process. I measure the resistors to ensure they are the correct value, solder them on the bottom, trim the leads, then solder the top of the board. Most people just solder the bottom and trim the lead. No matter the method, it won't take you long to get everything in place.

Populated Coda Pi Fuzz board...sweet!

If you're wondering about the parts used, they are Wima film caps, Vishay Dale mil-spec metal film resistors, and a Panasonic electrolytic. They tend to be the preferred parts for audio people, but you'll likely do just as well with their cheaper counterparts. I followed the Ram's Head Violet Era bill of materials (BoM) for this particular build. I had a good listen to various YouTube videos before I settled on it as my favorite of the bunch. Many people like the Green Russian, so give that a good listen as well. 

The cute little Alpha pots with non-conductive dust covers sit on the other side, no wiring to worry about. These are from Tayda Electronics if you are looking. "A" means audio log taper, and "B" means linear taper... so B25K means a 25K value pot with linear taper. Sorry, that will never show up on trivia night at your local bar. 

Alpha pots all pointed at you like torpedos

Just a heads up, but shoehorning everything into a 1590B is a tight squeeze. I should have drilled the pedal switch a bit lower, but I still made out okay. The great thing is the pots hold the PCB in place, no need for standoffs. 

So tight that I needed to mount the Panasonic capacitor sideways and give the transistors a bit of a gangsta lean. 

The 1/4" plugs fit perfectly. As you can see nearly all the real-estate is filled. 

And the final product, which sounds excellent. Lots of fuzz for your buck. The knobs are also from Tayda. 

Hope you enjoyed the build process of the Coda Effects Dolmen Fuzz Pedal. If you'd like to get started with a versatile effect with exceptional documentation, this is a great choice. Remember to use good quality parts like Switchcraft 1/4" jacks to ensure your new pedal lasts a good long while. Until next time!

Please remember that building/modifying circuits can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a build or modification posted above and cause physical harm to yourself or your surroundings. Many electronics contain high voltages that can kill, and mods, if performed improperly, can be a fire hazard. 

Matsumin Valvecaster Guitar Effects Pedal - Tube Overdrive

I've seen a few designs out there that starve a tube filament to maintain a low voltage and still provide nice results. The Matsumin Valvecaster is one of them. For those afraid to work with tubes due to high voltage (cue Electric Six, "Danger! High Voltage!"), this keeps the power at safer levels. It also allows a 9v battery to be used (or 12V) but will consume them fairly quickly... so an AC adapter is recommended.   

The design is nice and simple, and for beginning builders it's not too hard to follow the circuit visually. There are a couple of variations floating around, so if you're looking at multiple schematics or diagrams, be aware that they aren't all the same. Other builders have created their own unique pedals based on this design, but the values of the parts are different, so again, be aware ;) 

Matsumin Valvecaster schematic from hgamps

My favorite diagram/illustration was from David Smith. The input and output jacks are included as well as the 3PDT switch to bypass the circuit. David's illustration is intended for a turret board, but if you prefer point to point it's still easy to follow. Be sure to note the orientation of the 3PDT switch, it won't work if it's oriented differently (i.e. twisted 90 degrees). 

David Smith's diagram offers an easy-to-follow layout

Here's another diagram from Stompboxed, it's a little harder to follow but still helpful. 

Another diagram for reference. 

You'll probably want to use one of the larger Hammond 1590BB (or Hammond-style) chassis as I don't think trying to shoehorn this into a 1590B would be terribly easy. The 1590BB is available from the usual suspects, Mouser, Digikey, etc. in a variety of powdercoated colors. You can also go to Mammoth Electronics and get some much cooler paintjobs for a few more bucks, or go crazy with some waterslide decals... the sky is the limit. For this project I went with a purple Hammond 1590BB ... you can almost taste the grape looking at it.  

These are cast aluminum, so you need to treat them a little more gently than something that's extruded (e.g. try to do more drilling on the drill press rather than punching holes). Punching out the holes with a tool can sometimes take away more metal than you anticipated. 

I used larger Alpha pots in this build as I had them in the work-bin. CTS, Bourns and PEC also make good pots, and if you want to check out surplus, Clarostat and Allen Bradley are also great choices. The ceramic 9 pin tube socket is set against the chassis with a rubber "o" ring which can help quash microphonics. It's overkill for this build, but I had it in the bin. Beltons are cheaper and work great as well. 

There is a corresponding PCB to be used with CNC tube socket as the solder tabs are quite small to solder accurately. These can be found on Ebay by searching for "9 pin PCB", and Partsconnexion also carries them. 

The Russian PIO caps are a little on the large side and have metal shells, so they need to be carefully placed so they don't short any leads. They can also be covered with heatshrink. PTFE (teflon) tubing is placed on bare leads to ensure they don't short either. Also space needs to be given to the open-frame Switchcraft 11 1/4" jacks so they don't bump into any parts or wires when being inserted.  

Using different colored wire during the wiring process can help you visually follow the circuit if it doesn't work upon plugging in for the first time. Having a rat's nest of the same colored wire makes things much more difficult.   

Valvecaster wired up point to point

On top of the chassis a tube shield will be installed to protect the tube from an errant foot. You can find these in a number of anodized colors from Angela.com. I thought the gold looked nice contrasting against the purple. 

Top of the Valvecaster with Tube Shield off...

...and tube shield on

Hope you enjoyed the build process of the Matsumin Valvecaster Effects Pedal. You can see it's pretty easy to build a great effects pedal without a PCB and just a few parts. Remember to use good quality parts like Switchcraft 1/4" jacks, Alpha or CTS potentiometers, etc. to ensure your new pedal lasts a good long while. 

Please remember that building/modifying circuits can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a build or modification posted above and cause physical harm to yourself or your surroundings. Many electronics contain high voltages that can kill, and mods, if performed improperly, can be a fire hazard.