DIY pedal prototyper

[dbw]

The hardest part about trying out some new pedal designs is juggling batteries, pots, switches, jacks and so forth dangling off a breadboard.  Lots of hum, easy to get shorts, and the cat always tries to eat it.  So I made this puppy... it's basically just an aluminum enclosure with a bunch of breadboards on  top and the standard stompbox fixin's... a couple stomp switches, a few pots, a DC jack and two 1/4" jacks.

This gives me plenty of room to experiment with stuff easily.  Right now it's just a buffer, but I'll try out some fuzz circuits in a bit. 

The input jack, the DC jack, and a fuse holder.  On top is just a 1/2 hole with a plastic grommet, for running wires from the inside out.

Here's the buffer I've wired up.  A 4558 is actually a dual op-amp so I made two buffers but only one of them is connected right now.  One of the LEDs is always on when there's power, the other indicates if the pedal is on.

At the moment, only one of the switches and none of the pots are hooked up.  The switch in the middle disconnects the power.

 

[Mor Paul]

I'm looking forward to what you get out of that.

 

[RLW]

That looks like a GREAT idea.

 

[ocguy106]

That is cool.... I was looking into getting this http://blog.makezine.com/archive/2008/06/guitar_pedal_prototyping.html just to mes around with.

 

[Wana_make_a_guitar]

This looks pretty funky. Now you need one with a pedal for a distortion, like with the crybaby to slowly roll on the distortion and then slowly roll it off or chose a lower distortion setting in between. 

 

[dbw]

That is cool.... I was looking into getting this http://blog.makezine.com/archive/2008/06/guitar_pedal_prototyping.html just to mes around with.

Hey, cool, someone else had the same idea.  The price looks hefty but once you price out all the parts it seems OK.  If anyone is interested I can post the parts list for this thing.

 

[Nick Ellingworth]

I could probably get most of the stuff needed for that for free from my uni labs if I was careful (or if I threatened to take one of their oscilloscopes apart again), I used to muck around with making pedals but with no prototyping stuff I had to make a circuit and hope it worked, 9 time out of 10 it didn't.

I may try something like this at some point.

 

[blue313]

I'm definitely interested in the parts list.  Finally a good use for my old board from digital design class.

 

[dbw]

Hammond 1444-22 case
Hammond 1434-22 cover
Littelfuse 3455LF2 fuse holder
2A fast-blow 20mx5mm fuse
10x breadboard, Mouser p/n 383-A360
7x breadboard, Mouser p/n 383-A48
2x 1/4" jack
one of these: http://www.effectsconnection.com/oscommerce/product_info.php?cPath=2&products_id=37
two of these: http://www.effectsconnection.com/oscommerce/product_info.php?cPath=1&products_id=28
some plastic grommets to protect wires going through holes; I bought some at True Value for 59 cents each
pots, toggle switches, LEDs, whatever other goodies you want to add

You may also want a jumper kit, Mouser p/n 383-SWS2100
You definitely want some solid-core wire for connecting stuff.  And you'll need a soldering iron.

Of course you can get a smaller enclosure and fewer breadboards.  Maybe cut it down to one stomp switch.  But I like overkill

 

[stubhead]

You still have to solder the wires coming out of the bottom, right? And, are you planning to work out a clip, or terminal-type arrangement for each of the lugs on the pots, so you can keep the lugs clean? (Solder a component's wire to a clip, and clip it to the pot's clip....) This is really, really intriguing....

 

[dbw]

I was just planning to solder wires to the lugs of the pots and plug the loose ends into the breadboards.  Yes, I soldered the leads to the jacks, fuse, switches, etc.

 

[mayfly]

That's a cool idea.  BTW, a long time ago I did the same thing, except for tube amps.  I'll see if I can dig out my tube amp proto setups for some pics.

BTW - I didn't use a breadboard - I don't think it would have lasted very long without letting the smoke out. :tard:

 

[dbw]

Yup this is strictly for solid-state.    Unless you know of any tubes I can run off a 9v wall-wart  :dontknow:

My first project is going to be some sort of fuzzbox.  Then I might work on a guitar -> headphone amp.

 

[ByteFrenzy]

Aren't there some effects out there that run a tube off an 18v wart? They use a led underneath the tube to make it look like the filament is actually doing something and it's open to debate whether running your signal through a cold tube actually accomplishes something, but apparently having a 'real' tube on board is some sort of selling point...

 

[stubhead]

Hey, it looks like I have room here to fit a tube right inside my gee-tar! That solves everything. :blob7:

 

[mayfly]

Aren't there some effects out there that run a tube off an 18v wart? They use a led underneath the tube to make it look like the filament is actually doing something and it's open to debate whether running your signal through a cold tube actually accomplishes something, but apparently having a 'real' tube on board is some sort of selling point...

I believe that those units - and my Vox Tonelab is one of them - use DC to DC converters to get the voltage up to 120+ to bias the tubes.

 

[dbw]

This schematic is pretty complicated and partly in Japanese, so I may be wrong... but I don't see anything like that in here:

http://www.tonelab.net/files/ToneLab-service-manual.pdf

 

[kreig]

You still have to solder the wires coming out of the bottom, right? And, are you planning to work out a clip, or terminal-type arrangement for each of the lugs on the pots, so you can keep the lugs clean? (Solder a component's wire to a clip, and clip it to the pot's clip....) This is really, really intriguing....

+10

 

[mayfly]

This schematic is pretty complicated and partly in Japanese, so I may be wrong... but I don't see anything like that in here:

http://www.tonelab.net/files/ToneLab-service-manual.pdf

Cool!  where did you find that?

Yea - you're right.  They seem to be running the 12AX7 from the +/- 16 Volt rail.  That's a total of 32V, which although is likely enough to get the tube to function, is not what I'd call the sweet spot.

Hmmmm.  still sounds good though.

 

[dbw]

www.google.com

Type "vox tonelab schematic" and click I'm Feeling Lucky.  :icon_thumright: