Mood:  hungry

As regulars of the stompbox forums may already know, I recently traced out the schematic for my early 90's-era Pro Co Rat 2. I did this because I'm planning on modding it and I was dismayed to see that none of the schematics on the 'net matched what I had in front of me. The schematic can be found here:

http://www.aronnelson.com/gallery/d/17576-1/ProCo+Rat2.gif

Now, so people can see what I traced this schematic from, here are some gigantic up-close robot porn gutshots of the unit I traced. As far as I know, the schematic should match this exactly. A couple things to note; the IC socket is not original - I installed it years ago when I wanted to replace the opamp. The opamp in the pic is made by ST, the original was exactly the same except made by National - I still have it somewhere. I replaced the opamp because I didn't like the mushy sound it had and I thought maybe it was defective. It wasn't defective, the pedal sounded exactly the same when I put the ST one in. I now know that the mushy sound is part of the usual thing these Rats do. I plan to mod it to get rid of the mush and give it more sizzle.

Here's the stupid pics already!

Posted by soulsonic1978 at 7:27 PM EST

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Mood:  caffeinated

How's everyone doing out there? I haven't done an update in two months... sorry about that, I guess I'd been waiting to have something interesting to put up.

 Here's an interesting little box I built for my friend Alex:

Nice, aye? It's not the cleanest work I've done, but I am pleased with how the finish came out toughness-wise. The gloss coat is Rustoleum laquer that I "baked" with a heat gun. I'm pretty much hooked on the heat gun technique now, and I'm not going to poison my oven any more by baking boxes in it. Heat gun all the way! It's so much easier to do with less guess work (you can watch it all happening as you work on it) and the fumes don't concentrate in one area like when you use an oven, and it would be easy to set up a fan for some ventalation.

But what about the inside? The circuit itself is pretty simple; a basic non-inverting buffer feeds two output buffers that have polarity reversing switches that allow them to be either inverting or noninverting amplifiers. The polarity switching circuit is a basic thing found in The Art of Electronics. The whole pedal is just some textbook circuits being powered by a application note MAX1044 power circuit.

The MAX1044 is used as a negative voltage generator to give the opamp a true bipolar supply. In the majority of cases, I always try to run an opamp from a bipolar supply whenever possible. It allows the cleanest sound with the widest dynamic range. In the case of this circuit, it can take an input level of about 8 volts before it will clip.

Here's a couple pics of the board:

I did the usual perfboard thing that I'm known to do. I mounted the switches directly to the board so it would be easier to mount it in the box. I probably agonized for an hour about how the hell I was going to mount it and still have room for the battery. Then finally, I realized it would be really easy to mount the switches to the board and build it up around them. It made a couple things about the layout a little weird, but whatever, with perfboard it's very easy to work with all three dimensions in a way that's almost impossible with PC boards.

What's with the missing socket contacts? Those were removed to make it easier for wires to pass on the wiring side of the board in a couple trouble spots. The are pins that aren't used.

Here's a couple more pics of the wiring of the footswitches and LEDs and then finally, everything together.

Posted by soulsonic1978 at 6:45 PM EST

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Mood:  chillin'

Okay here is the newest updated schematic for the Shizzle.

For whatever reasons my pics haven't been showing up where I stuck them in some forums. I'm wondering if I'm exceeding my bandwidth on Photobucket? Whatever... you will always be able to find the full articles and images here, so screw 'em. 

Posted by soulsonic1978 at 9:53 PM EDT

Updated: Friday, 31 August 2007 10:05 PM EDT

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After much turmoil and violence, I finished a Shizzle pedal. I shouldn't have so much trouble with something that's my own design! But, I chose the hard route what with all the hand-wiring craziness...... Anyway, after all was said and done, I finally have what I would consider to be a final circuit for the Shizzle and also what I would consider my final layout.

Looksi here:

Beautiful, I know, you don't need to tell me. :wink:  Ah, if only you could hear this thing! It's very hard to describe a three-stage Germanium transistor fuzz as a smooth tube-like overdrive, but that's exactly what this thing can do! That's what makes Shizzle special, and why I have disdain for those people who thing fuzzes are put on this earth to make squealing noise.

I promise, I swear, I vow that later this weekend I will have sound samples of this thing up so you can hear what I'm talking about. I really wish I could do a video so you can watch me tweaking the knobs, but all I have available is a shitass webcam and I'm not entirely sure how I would manage recording audio and video simultaneously. My guess, is I'd probably use two machines to do it and sync them later. I say that because I want the recorded audio to be of good quality, so I'll have to do that with my desktop, but all my video ability is on my laptop..... hmmmm, yes - need to figure something out for that...

I will update this topic later later to give more info about this astonishing circuit. I know there's probably some ass out there who'll say something like "that's already been done... blah blah blah" - well, fine, if it was I didn't know about it. I came up with the idea one day when I was using my Rangemaster to boost my Fuzz Face. Then I built the thing and while I was tweaking it, I discovered all the awesome variations available, which I've never heard on another box, so whatever, I don't care how original the circuit is, I'm not trying to patent it. Nothing magical here, just a cool sound.

Posted by soulsonic1978 at 6:33 AM EDT

Updated: Friday, 31 August 2007 6:51 AM EDT

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Mood:  not sure

Greetings everyone in the DIY community. Welcome to The Illuminist! In this blog I'm going to try and keep track of all my builds so that others might learn from my many mistakes. I will also attempt to share as much knowledge and info as comes spilling out of my head when I tilt it too much.

These pages are dedicated to DIY Electronics - specifically circuits for musical instruments. The primary focus is going to be on pedals and amplifiers; though I might just put whatever. My goal is to try to put together something as informative and interesting as the great community of Japanese DIY blogs... there's some really great information to be found there!

 Another thing I plan on focusing on is vacuum tube circuits. I've been a fan of valve technology since I was in high school and got my first tube amp - an old Silvertone 1482; and when I got the amp it had a broken fuseholder, so my first tube amp also became my first tube project! In the approximately 14 years since that time, I've repaired, built, and modified many tube amps of all different sizes and styles. My favorite circuit to work with the the Soldano SLO100 circuit; it has been the basis for many popular high-gain amps and there's really alot to work with as far as variations on the basic theme of that circuit.

 Anyone who needs to contact me for any reason, please send email to: soulsonic1978 @ lycos.com

Thanks, and please use the information presented here, "wisely"...

-Martin Chittum 

Posted by soulsonic1978 at 3:22 PM EDT

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