Introduction: Lunchbox Synth

Picture of Lunchbox Synth

Crammed a digital delay, spring reverb and function generator into a lunchbox. The fact that it says korg is sort of a synth geek joke. _ Big thanks go out to and for being such great resources for this beginner. All boards etched by me using press-n-peel blue and RadioShack etchant.

audio samples are here for all settings full and here for a little restraint


afridave (author)2016-09-21

not bad considering its 72000 years old.....they just don't make em like they used to...rock and roll an all...

noahh (author)2011-11-24

I remembered your synth when I was at Goodwill looking for an enclosure for a project and bought a lunchbox for it. Thanks for the cool idea.

pstretz (author)noahh2012-01-05

<3 your project! sounds great, glad I could help inspire. :)

riverreaper (author)2011-07-29

ive an old casio key board i just gutted ive plans to put it in somesorts box , with were the keys press down on swiches {is a 2 parter} on the surface along with its other pad switches , im still searching for a good containr . im wondering if any of the digital delay, spring reverb and function generator would work hooked to it as well for added sounds , it has midi in/out but my kore2 synth is already in use with upgraded devices . have you seen any keyboard hacks that look easy ?

AmericanPringles (author)2011-03-29

I love this. I was thinking about building a lunch box synth but with the control panel inside instead of using the metal lid. Then it would be its own case as well.

pstretz (author)AmericanPringles2011-03-29

That's a great idea! Also it'd be a little easier to assemble. ;) I'm finding that the solid core wire i ended up using for convenience is starting to break since everyone wants to see inside and they flex when I open the door. :( I recommend using a clear plexi/acrylic for your panel so everyone can see the guts without taking the box apart. Also post a pic or a link when you get yours done. I'd LOVE to see it! Happy Making!

rapyourself (author)2010-03-13

Hello there, I'm making an experiment based on non-newtonian fluids and I need to build a analog frequency emissor, i mean like this:, but analog, something like what you got here..I don't understand much about electronics and i tougth maybe you could help me or recommend a site that could be useful to me..thankz

pstretz (author)rapyourself2010-03-15

 I'd be happy to help.  Please PM me about what you need to do and we'll see where to go from there.  :)

rapyourself (author)pstretz2010-03-16

what do you mean by PM? I'm sorry, but I'm not english and I'm not familiar with some terms :( sorry again

pstretz (author)rapyourself2010-03-16

Sorry.  PM is Private Message.  You can do this by clicking on my user name and then click the Private Message me button.  :)

Nucleus (author)2009-03-09

Hey, does this synth can modify INPUT of music? Example "Cigar Box Guitar"

pstretz (author)Nucleus2009-03-10

No, not by design, but you could hook it up to a ring modulator as the carrier signal or if you just wanted the reverb and delay, you could put a switching jack to bypass the function generator and plug in any sound you want.

Dr_Stupid (author)2008-08-16

did you choose Korg as the lunchbox because of Korg and their synthesizers? or was that just by happenstance?

pstretz (author)Dr_Stupid2008-08-18

that's absolutely why i chose it. I was looking for a space themed lunchbox, but when i found this, it was too good to pass up. :-) I hope to put together a kit similar to this soon.

Orannis (author)2008-05-08

XD Korg. I need to try this.

Axlzero451 (author)2008-04-13

I got the korg joke. Does that make me a synthesizer geek?

tmurder (author)2008-02-24

how did you power the whole thing? looks like dc from a wall converter. how then, did you get the -9v for the reverb?

pstretz (author)tmurder2008-03-13

i just used a charge pump converter IC. very handy circuit to have lying around. all the details here

tmurder (author)2008-02-03

are you using an xr2206?

pstretz (author)tmurder2008-02-04

I just used 1458 op amps because that's what I had. really anything that makes sound would work. you could replace what i have here with an atari punk console if you wanted to.

tmurder (author)pstretz2008-02-04

fantastic! this was exactly my solution, i've already made one. thanks for the inspiration!

pstretz (author)tmurder2008-02-05

i'd love to see it. please post a pic. :-)

tmurder (author)pstretz2008-02-15

er i meant i had built the atari punk console. still waiting for a few parts in the mail.. i'll post a pic when its all done :)

conceptualstratagem (author)2008-01-27

I'm impressed, thanks for sharing this. PLZ PLZ PLZ make an instructable, so many builders here want to get more familiar with these kits.

will do. it'll take a little while though.

bowmaster (author)2008-01-21

PLZ PLZ PLZ Make an instructable

pstretz (author)bowmaster2008-02-04

will do. it'll take a little while though.

tmurder (author)2008-01-31

what does your function generator look like? or, can you point me to diy plans/resources on building one? i didnt see any on tonepad

pstretz (author)tmurder2008-02-04

function generator i used was found on page 10 of this pdf. i took each output and used a 10K pot and 10K resistor to make a mixer like-a-dis i didn't bother with the op-amp so i connected used the audio out where R7 is. that way i can mix the 3 waveforms together and get a different sound. hope this helps. i want to add an envelope filter and then create a pcb layout so the whole thing is on one board and has a single header for the wiring. instructable will be posted when i choose a filter i like.

incorrigible packrat (author)2008-01-24

The all-out sample sounds way "Forbidden Planet". Sweet!


You're welcome. I thought of a splendidly obscure synthesizer reference; if you used an old "Tears for Fears" lunchbox, featuring Roland Orzabal and that other guy. Only a select few would get the joke. Of course everyone else would merely mock you for having a "Tears for Fears" lunchbox (not that there aren't far worse bands to have lunchboxes of).

GorillazMiko (author)2008-01-18

Awesome job! If you post it as an Instructable, I will have to show this too my friend, great job.

Patrik (author)2008-01-18

That's great - excellent choice of lunch box! :-D Is that a red LED for the mastodont's eye?

pstretz (author)Patrik2008-01-18

no, it's a momentary switch so I can trigger the audio to the digital delay. The switch in the mastodon's mouth switches from continuous output to momentary output. that way I can change frequency without hearing it then push the button and send the audio to the delay. _

gmoon (author)2008-01-18

HaHaHa...that's marvelous! (I've got an X-Files lunch box I might use for something similar...) But many unanswered questions: -- What's the signal input? Is it self-contained "twiddling" or some other signal source? (probably internal , triggered with that big red button, right?...) -- Schematics? -- Sources (reverb tank, etc?) -- More / better documentation?

pstretz (author)gmoon2008-01-18

there is no input. I'm using an op amp function generator into a resistor matrix for creating sound, it passes through the delay, then reverb. You can mix the amount of sine, triangle, or square wave with the 3 knobs at the top. The red knob is pitch/frequency. I didn't have complete instructions for this and that's why it's a slideshow, not an instructable. the parts I had lying around so really it was just like $15 for the lunchbox. Ask any questions you need to and I'll do my best to answer them.

About This Instructable




More by pstretz:First Modded SK1Microcontroller Fabric Tone Generator in C-codeControlling Cubase with Arduino based MIDI
Add instructable to: