Pedalmaking Paradox
Um, what’s that all about? Yeah I dunno, something. So I was snooping around the internetz (ie, killing time at work when I damn well had other More Important Shit that needed doing) and found a site that hosts veroboard/stripboard layouts for clones of like two hundred pedals or something. Hmmmm this could be interesting, I thought.
For no reason at all, at least not one I can recall, I started my trip through that site at a page about a clone of the Emma Transmorgrifier, which is a compressor pedal that uses an old, out of production, semi-pricey but not impossible to find CA3080 chip. The CA3080 is a special kind of operational amplifier; it’s an OTA—Operational Transconductance Amplifier. I can’t really even begin to explain what’s different or special because I hardly even have a clue myself. In any case, this chip found its way into a number of devices in the music-making arena, like synths, especially in filters. Info I’ve read said that Roland used OTA based filter designs in their SH-1 -5 and -7, as well as the System 700, and anything with an IR3109 which means Jupiters and Junos, and even the JX-3P, and JUNO-106. Later generation Korg MS20s, and various synths that used Curtis filters (OB-8, Matrix-12/Xpander) also used OTA based filters.
The CA3080 didn’t just do filter duty though, as it was evidently also used in VCO and VCA circuits, and for a handful of other synthy guts jobs to boot. But that’s not all! The chip ended up in something like 90% of compressor pedals, which is what I wanted to talk about in the first place. I dunno why but I love compressor pedals, and I especially love using them on things like synths and drum machines and other weirdo gear that they were never designed specifically to play nicely with in the first place. I place the blame for my interest in using compressor pedals this way on Legowelt. I saw him talk about running his 808 through a Boss CS-3 and was like “huh?” That started it. Of course, I have a CS-3, and have modded the flying fuck out of it, and I do use it every now and then, but I was looking for something with a different flavor. Coincidentally, the CS-3 uses a VCA circuit, which gives different results than an OTA circuit. Anyway...
So the transwhateverifier looked neat and not all that hard to put together so why not? After a week all the necessary parts had been ordered (Tayda rocks the house, it’s cheaper for me to order from them and have it shipped here from overseas than to go into Osaka and buy parts). Soon afterward everything had been delivered so it was time to get busy with construction. I’d never used veroboard/stripboard, so I was a tad nervous about the whole affair at first. Making cuts and running links was easy though, and as long as you PAY CLOSE ATTENTION TO THE PLAN, you should have no problems. Actually, the pedal worked from the first time I powered it up so I was very pleasantly surprised. Here’s some photos.
The innards. I cheated and used a nifty little PCB from Tayda that makes all the connections between the stomp switch and the main PCB and the LED and everything. Fucking brilliant. I put Scotch Super 33+ electrical tape on the underside of the veroboard, just in case the line of hot glue there along the bottom that sorta attaches it to the wall of the case there comes undone. Don’t need any shorts. Coulda used longer wires to the power jack. The audio jacks are parts I cannibalized from an Alesis Photon controller keyboard I bought as “junk” when I needed knobs for the ION.
I used clear knobs and an egg-yolk pastelish yellow LED just for shits and giggles. Doesn’t look half bad really.
And lastly here’s a photo of the CA3080 I used. Neat looking old tin can of a chip!
I was so chuffed with my successful build of the compressor that I went right to the next pedal project without hardly pausing to catch a breath. An Analog Bit Crusher!!! Yeahhh!! WHAT?! Analog?! Yep. No idea what the fuck wacko bastard figured this shit out. Two bog standard TL072 op-amps and a sorta hard to get transistor (2N5457) and That. Is. It. One knob. Works like fucking magic. I’ll blab about that one once I get it in a case and all.
Oh one BIG FACTOR here with me deciding to have a go at building veroboard clones is how goddam cheap it is (aside from sourcing the hard to find components I mentioned above anyway). The Emma Transmorgrifier runs a cool €159 plus shipping. I think I paid less than $45 to build the clone. The Analog Bit Crusher was like $25. So if you’re on a budget... have wife & kids to support... have a wife/girlfriend/parent that you have a hard time convincing that No Amount Of Gear Is Ever Enough... DIY is a goddam lifesaver.