|The Multi Rat Schematic|
Thursday, November 15, 2012
The 60's and early 70's were all about driving tube amps into overdrive heaven and on the way use fuzz and treble boosters to get the job done. Most Fuzz stompboxes were, in fact, so effective that you didn't really need the amps to be that heavily driven anymore, but they killed most of the guitar's tone and dynamics. They took over the sound (Fuzz faces and Big Muffs to name a few).
As people got fed up with fuzzes and wanted back that dynamic distorted overdrive, Orange amde the first step and came out with their Overdrive amp in the mid 70's. That started the distortion race all over again. The idea of a stompbox giving you that distortion, which was so important for rock guitarists, yielded the next step in the second half of the 70's. In 1976 Amlyn Crowther designed the Hotcake which would become the first boutique overdrive (Sonic Youth, Pavement, Radiohead, Protishead and many other consider it their "secret weapon'). Japanese based Ibanez and Boss came out with the classic Tube Screamer and the OD-1 (DS-1 too), respectively, around 1978. In Kalamazoo, Michigan, two guys in a basement started selling custom ordered pedals under the Pro-Co name. Those were the first Rats. All the above brands produced pedals based around an operational amplifier and have some similarities in their designs. All three became classics and over the years got reissues, sequels and modified versions.
I decided to build the Rat for 3 main reasons: a) It is a classic pedal and deserves FuzzQuest attention. b) Some of my favorite guitarists use it or have used it over the years. C) There is no real mojo in this circuit. the LM308 chip and clipping diodes are all pretty straightforward. No Germanium PNP or de-gooped old boxes with debates over them. The amount of schematics on the web is infinite and the mods are all given out. You can build the circuit with mods and it will sound just like the real thing. Even better. Guitarists who used this unit and made it famous were Thom Yorke, Thurston Moore, Stephen Malkmus, Bernard Butler, Marc Ribot, Bill Frisell, Frank Black, Jeff Beck, Andy Summers, Graham Coxon and Kurt Cobain, to name a few. If you told me only Thurston and Ribot were on this list, it would have been enough for me. This might have been the overdrive/distortion used by Ribot on Rain Dogs by Tom Waits. Imagine that!
So, I gathered about a dozen schematics I considered to be trustworthy. RG Keen and Jack Orman did some tremendous work given on the aron nelson archive and diystompboxes. You can download the schematic shown here, but Beavisaudio, GGG, Sabrotone, SoulSonic, Gaussmarkov and others, all have verified circuits readily available, just click the links.
I added the Ruetz mod to conttroll the highs and called it EDGE. Got an On/Off/On switch for choosing between the diodes, MOSFET clipping and clean boost and named it CHARACTER. DISTORTION FILTER and VOLUME are similar to the original. Apart from that it's a vintage Rat clone. The added mods give it a lot of "elevation" so I called it the BAT. Also I liked the Mokafix Bat VST emulation and adopted the name. It really is a mouse with wings.
So I got the circuit working and painted the enclosure. I really dig the sound which sounds pretty awesome especially with my English Channel emulation of the AC30. I completely understand why this became a classic unit. This is the distortion we grew up on listening to grunge, alternative and punk rock from the 80's and 90's. Great sound, versatile, easy to use. Humbuckers with an AC30 you get the British indie rock of Suede and Blur. Single Coils with Fender amps will give you Sonic Youth and Pavement flavors. Pretty Amazing. With the clean boost mod you can get great fuzzy overdrive and you can drive other pedals on the chain or drive your amp further. Super!
As always, if you want audio demos you have to comment and ask for it. I hope to get some clips done for all my posts but it's gonna take a while since I am on a building mania and even posting on the FuzzQuest blog takes me forever.
Anyway, a very recommended build. Pretty easy and fun with a lot of options. With the Ruetz mod attenuating the highs and the clean Boost which is not so clean I got some wicked fuzz sounds. If you are wondering, you can be sure that a Tube Screamer clone is on the way. Naturally.