The Song Fight Bulletin Board

just finished my first electronics project in 20 years.. I made a whacky little distortion "pedal" - quotes because it's not in a case and has no on-off switch.

http://photos1.blogger.com/blogger/21/3 ... 010088.jpg

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it cost 5 or 6 bucks and sounds like this

http://www.sonofsupercar.org/music/gom/pedal-snip.mp3

that's a DI recording w/nothing on it. 74 Univox Mosrite.

there's tons and tons of schematics and helpful info online for doing stuff like this yourself. even having to buy a soldering iron ($30) and a breadboard ($15), it's still pretty cheap to make things, and way fun.

So what kind of circuit is it? Germanium Fuzz?

Ken

Did you follow a schematic or is that original?

Over Christmas break my dad and I made this absolutely brutal-sounding distortion/filter basically on accident. It got to be in one noise concert and now it's not working and covered in eggs. We're planning on making a phototheremin over Spring Break.

I was actually planning a phototheremin project for when I get back home over the summer, plus a couple of condensor mics (thanks to anti-m for the link in some other thread, I think).

That's really cool blue.

it's an lm386-n .25 watt amplifier through a pair of silicon diodes. all the op-amps i tried just weren't giving me enough gain - this one has a gain of up to 200.

blue wrote:there's tons and tons of schematics and helpful info online for doing stuff like this yourself. even having to buy a soldering iron ($30) and a breadboard ($15), it's still pretty cheap to make things, and way fun.

Could you post a "for example" link or two?

For example, start with http://www.geofex.com .

Blue: it looks like the wires you're using are too thick. They will crack eventually through bending, vibration, etc.-- you want to use stranded wire for the off-board connections.

Also, a typical op-amp should be capable of way more gain than you were getting. Has to be wired right, though, and it's not exactly intuitive.

yeah, i know my wires suck, and i know i should have used stranded everywhere. i did use it for the +/- rails (for no good reason). i was using single-strand everywhere for breadboarding, and then i just moved them over and soldered them down.

the 386 is an op-amp, it's just a high-power one. "plenty of gain" is subjective.

i used a ton of diff op-amps in prototyping, and really just ended up using this one because it was the fewest components for the most gain. (it's single-supply, etc) with a regular op-amp i'd at least have to add a voltage divider.

it is not a masterpiece. it's some junk i managed to get soldered to a board that passes audio.

here are some of the links i frequented:

http://www.uoguelph.ca/~antoon/gadgets/741/741.html

http://www.swarthmore.edu/NatSci/echeev ... upply.html

http://cygnus.ipal.org/mirror/www.passl ... yopamp.htm

http://icc.skku.ac.kr/~won/electro/basics.html

http://www.tpub.com/neets/book7/25c.htm

it took me almost a month, maybe 2, of weekend hacking to get comfortable enough to go ahead and solder something together.

if anyone can find a good DPDT footswitch for less than $10 each, let me know. they seem to be scarce.

This was my first electronics project ever. It's a distortion pedal, it has no controls, it clips the signal like mad. If you wish it can be heard on this very old song on several of the synth parts.
-bill

i got my parts from this dude on ebay -

http://stores.ebay.com/NightFire-Electronic-Kits

i got the DIP op-amp kit #3, which came with some cool wee speakers and switches and crap. make sure you get DIP and not SMC (surface mount). it was a little slow in shipping, but lots of parts for $10. the sockets came from radio shack (and are shit).

you can use the 555 timer in that kit to make a square-wave oscillator.

Oh, yes: http://www.elixant.com/~stompbox/smfforum/ Best place to go.

The guy who runs this sells good switches for $6.25, which is less than they're worth.

Edit: a good place to buy parts and such is http://www.smallbearelec.com .

I don't know shit about building them. But man I do love buying 'em, housing 'em, and playing the shit out of 'em. Especially these mostly vintage guys

I got a buddy who's been building amps the last 3 or 4 years. I've been on him to do pedals. I'm going to give him some of these links to try and entice him further.

bzl wrote:Oh, yes: http://www.elixant.com/~stompbox/smfforum/ Best place to go.

The guy who runs this sells good switches for $6.25, which is less than they're worth.

Edit: a good place to buy parts and such is http://www.smallbearelec.com .

smallbear is the one i was trying to remember. also, if you must have germanium transistors, you can usually get them in batches on ebay for way less than people sell them on the DIY sites.

blue wrote:also, if you must have germanium transistors, you can usually get them in batches on ebay for way less than people sell them on the DIY sites.

That's a bad deal, though, because the seller has already tested them all and taken out the useful ones.

The original Fuzz Faces are the textbook example here. Sometimes, you got one that sounded great, but many were crappy-- with the exact same circuit in both. Eventually people figured out that it was because the germanium transistors had a lot of variability. It's just the manufacturing: there's no way to make consistent germanium parts, which is one of the reasons why everything is silicon now.

Basically, if you're serious about getting Ge parts for music, you buy a million of them and measure them all. You keep the handful that have the right gain, and throw the useless ones on ebay. This may sound excessive, but it's how almost all "boutique" pedals are made. They're mostly based on a couple of well known, very simple circuits (the Fuzz Face and the TS-9 are common) but with better quality control.

On the nice side, some folks will sell you small lots of transistors that do test well (or "matched pairs" which are useful occasionally) but of course that's not as cheap.

Further reading is here.

ah, good point. or i guess if they're really what people claim they are ("old lots i found in a suitcase, etc") chances are good that they're all shit anyways.

fuckers.

Also beware of anything tagged "estate sale". It's bullshit. It just means they couldn't dump it anywhere else.

Hey, no compliments on my pedal board? Damn.

i gave you one mentally. love those old bluetube/realtube pedals.

That is one neat looking chorus. Actually, the cases are usually a lot harder to make than the circuit that goes inside, especially if you want it to look good. It looks like it might be hard to step on the black thing in the upper left. Have you tried a two-tier pedalboard?

The only discrete parts that you have to worry about going bad with old age are electrolytic caps-- they have liquid inside and it tends to dry out after a few years. (That's why your amp tech offers a "cap job" service: the high-power capacitors, at least, are usually electrolytic, and need replacing about once a decade. Don't try this yourself.) So they might not be lying to you on ebay, but, well, they probably are and it sure ain't worth the risk.

Doh

blue wrote:i gave you one mentally. love those old bluetube/realtube pedals.

Me too, but my favorite is that Boss CE-1 in the lower left corner. Even in mono it makes the sweetest Leslie sound you ever heard.

Thanks for the mental nod.

bzl wrote:That is one neat looking chorus. Actually, the cases are usually a lot harder to make than the circuit that goes inside, especially if you want it to look good. It looks like it might be hard to step on the black thing in the upper left. Have you tried a two-tier pedalboard?

Yeah that's the one I'm talkin' 'bout! It is sweet, and built like a tank. You could drop it down the steps and the only thing you would need to repair would be....the steps.

I thought about the 2 tiered thing, but the one I have was like $150 which seemed like enough money spent on a case. The one cord isn't as bad as it looks and could be rectified with a longer cord. I just prefer the connections to be as short as possible. Maybe a re-arrangement of the pedals.

Anyway, I don't mean to sidetrack this thread, I'm just a pedal lover.

Blue, let's say some asshole (me) has no idea about caps, boards, soldering or apptitude for such things. Where would you suggest he (I) begin?