lunchbox synth

 by pstretz
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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 tonepad.com and generalguitargadgets.com 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
noahh says: Nov 24, 2011. 11:04 PM
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.
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pstretz (author) in reply to noahhJan 5, 2012. 6:31 AM
<3 your project! sounds great, glad I could help inspire. :)
riverreaper says: Jul 29, 2011. 7:03 AM
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 says: Mar 29, 2011. 4:16 AM
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) in reply to AmericanPringlesMar 29, 2011. 5:39 AM
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 says: Mar 13, 2010. 6:39 AM
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: http://lab.andre-michelle.com/wavepole-synthesizer, 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) in reply to rapyourselfMar 15, 2010. 7:51 AM
 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 in reply to pstretzMar 16, 2010. 12:54 PM
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) in reply to rapyourselfMar 16, 2010. 1:18 PM
Sorry.  PM is Private Message.  You can do this by clicking on my user name and then click the Private Message me button.  :)
Nucleus says: Mar 9, 2009. 10:25 AM
Hey, does this synth can modify INPUT of music? Example "Cigar Box Guitar"
pstretz (author) in reply to NucleusMar 10, 2009. 4:47 AM
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 says: Aug 16, 2008. 10:39 AM
did you choose Korg as the lunchbox because of Korg and their synthesizers? or was that just by happenstance?
pstretz (author) in reply to Dr_StupidAug 18, 2008. 5:18 AM
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 says: May 8, 2008. 7:18 AM
XD Korg. I need to try this.
Axlzero451 says: Apr 13, 2008. 10:31 PM
I got the korg joke. Does that make me a synthesizer geek?
tmurder says: Feb 24, 2008. 2:20 PM
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) in reply to tmurderMar 13, 2008. 3:33 PM
i just used a charge pump converter IC. very handy circuit to have lying around. all the details here
tmurder says: Feb 3, 2008. 9:57 AM
are you using an xr2206?
pstretz (author) in reply to tmurderFeb 4, 2008. 7:40 AM
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 in reply to pstretzFeb 4, 2008. 3:25 PM
fantastic! this was exactly my solution, i've already made one. thanks for the inspiration!
pstretz (author) in reply to tmurderFeb 5, 2008. 4:08 AM
i'd love to see it. please post a pic. :-)
tmurder in reply to pstretzFeb 15, 2008. 8:39 PM
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 says: Jan 27, 2008. 3:04 PM
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.
pstretz (author) in reply to conceptualstratagemFeb 4, 2008. 7:41 AM
will do. it'll take a little while though.
bowmaster says: Jan 21, 2008. 5:58 AM
PLZ PLZ PLZ Make an instructable
pstretz (author) in reply to bowmasterFeb 4, 2008. 7:41 AM
will do. it'll take a little while though.
tmurder says: Jan 31, 2008. 3:05 PM
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) in reply to tmurderFeb 4, 2008. 7:35 AM
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 says: Jan 24, 2008. 7:44 AM
The all-out sample sounds way "Forbidden Planet". Sweet!
pstretz (author) in reply to incorrigible packratJan 25, 2008. 7:13 AM
thanks
incorrigible packrat in reply to pstretzJan 28, 2008. 6:11 AM
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 says: Jan 18, 2008. 5:33 PM
Awesome job! If you post it as an Instructable, I will have to show this too my friend, great job.
Patrik says: Jan 18, 2008. 10:45 AM
That's great - excellent choice of lunch box! :-D Is that a red LED for the mastodont's eye?
pstretz (author) in reply to PatrikJan 18, 2008. 12:01 PM
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 says: Jan 18, 2008. 8:55 AM
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) in reply to gmoonJan 18, 2008. 9:39 AM
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.
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