The Oddball Muff - The Op Amp Version...

Another Big Muff Pi variant! I know those of you who read this blog semi-regularly are shocked... shocked! That being said, this one is actually a bit different. In 1977, Electroharmonix engineer Howard Davis was tasked with redesigning the normal BMP circuit to use op-amps rather than transistors for the gain stages. While some purists do not consider the op-amp version to be a "real" Big Muff, it's simply called the version four on Kit Rae's page. One of the best known users of this particular variant is Billy Corgan who used the V4 on the 1991 Smashing Pumpkins album Siamese Dream among others. For this build I'm using the AionFX Corvus board in the base build configuration for the project incorporating the tone bypass toggle and the variable gain-stage modification developed by Analogguru. Original versions of the pedal can cost upwards of $500, but new versions can be had for about $100 - so it's a decent DIY opportunity, but nothing compared to more boutique offerings.

As you can see from the photo above, I went ahead and built a couple of these. They're both identical electronically. Although the AionFX board allows you to build the original 1978 stock version without the Analogguru mods, I went ahead and went with the standard build as presented in the Corvus project which includes those modifications. Despite this being an early pedal design, I've gone with all modern components from the resistors and capacitors all the way through the diodes and ICs. My stock of certain key vintage diodes and other components is starting to dwindle, and I really want to reserve those for the more classic pedal designs. 

The build itself is extremely straightforward, and it follows the normal AionFX layout with a daughter board for the 3PDT stomp switch. I went ahead and included the battery connection for serial number 2, but I left it out of serial number 1 as I'm out of cables at this point, and #2 will likely go to someone else. Once again all of the connections to jacks are wrapped in heat shrink tubing to protect the connections. 

Once again I've had a bit of fun with the case and its enclosure art. So now the final pedal in the "teaser triumvirate" from my earlier production update has been revealed (though this one was likely fairly obvious from the outset). I'm experimenting with a couple of different knob configurations. I really like the silver knobs (serial number 2 above), but I'm also trying out the green knobs (serial number 1 below). I think the green on #1 is a bit dark. It's not bad, but the silver I think works better. Unfortunately I only had about 4 of those knobs available and they appear to be out of stock everywhere. So until they're back in stock, #1 will be rocking with the green knobs.

As to the sound - it is unmistakably a Big Muff, but it really does have a different feel to it in many ways. If you want to play Smashing Pumpkins from Siamese Dream or even as late as Mellon Collie and the Infinite Sadness, here is that sound in one convenient box. That being said, it will also work anywhere you'd use a regular BMP, but you'll need to work with the settings a bit. Honestly I really like the sound overall, and I'm glad I finally got around to adding one of these to the stable!