Transplanting synthesizer parts

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Bingo
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Transplanting synthesizer parts

Post by Bingo » Wed Jun 10, 2020 11:33 pm

Please don't laugh me off the face of the earth. Has anyone ever transplanted synthesizer parts (oscillators, filters, ADSRs) the way you would do in the medical field? I was looking at the filter on my arp Axxe, it's like a module. Could you just take that off, disconnect the filter of another synth and just wire/drop the Axxe filter in? what happens? The filter in my SY-1 is a module. If I could wire that into my Cat for example I'd have one bad a*s synth. It certainly has the room inside of it.

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Re: Transplanting synthesizer parts

Post by Alex E » Thu Jun 11, 2020 1:23 am

What you're describing isn't possible. You could transplant Arp Axxe parts into another Arp Axxe but not a different brand of synth altogether. All these instruments are designed differently, so leave the mods and DIY stuff to the pros.
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Re: Transplanting synthesizer parts

Post by meatballfulton » Thu Jun 11, 2020 1:59 am

What you are asking for is what modular synthesizers are all about: freely exchange modules to your personal taste. Of course, you give up a lot of convenience with modulars which is why they fell out of favor for so long (most of the 80s and 90s).
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Re: Transplanting synthesizer parts

Post by elsongs » Thu Jun 11, 2020 2:28 am

Bingo wrote:
Wed Jun 10, 2020 11:33 pm
Please don't laugh me off the face of the earth. Has anyone ever transplanted synthesizer parts (oscillators, filters, ADSRs) the way you would do in the medical field? I was looking at the filter on my arp Axxe, it's like a module. Could you just take that off, disconnect the filter of another synth and just wire/drop the Axxe filter in? what happens? The filter in my SY-1 is a module. If I could wire that into my Cat for example I'd have one bad a*s synth. It certainly has the room inside of it.
Like the medical field, it is possible -- but only if the parts are compatible. There may be some cross-compatibility among different models/manufacturers when it comes to certain components -- keybeds are the most common - but in most cases, they are not. Just like in human organ transplanting, one needs to do research first to ensure compatibility.

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Re: Transplanting synthesizer parts

Post by Bingo » Thu Jun 11, 2020 4:35 am

Thanks for the well-written replies. I guess I should have figured. It is true that I had modular synthesizers in mind. I figured if it can work for modular synths why not for non-modular. Oh well. If I could keep everything the same on my Cat (the modulation, the sync, etc) but put in two Axxe/oddy VCOs instead, and also replace the filter with the sallen-key one from the SY-1 I would have a dream synthesizer. I guess those are custom sounds I'll never get to hear.

Edit, I know this is going to sound crazier yet, but can some expert out there take my Axxe and put its vco in its own module? how much would that cost?

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Re: Transplanting synthesizer parts

Post by madtheory » Fri Jun 12, 2020 5:36 pm

You're better off seeing if there are modifications available for the Axxe. To give you direct VCO outs, and other facilities. It is a lot of work to break a synth like that into its sections.

To answer your question, it is totally possible. The audio and CV signals are pretty much the same on all analogue synths. If you've a synth that's Hz/V instead of V/8ve that needs to be converted, but again it's do-able. But you would really need to "modularise" the whole synth, otherwise (in most cases) you are looking at cutting up a PCB. Again, that's possible, but it is risky and requires great care and experience. Some synths lend themselves to this- for example, the bits of SH-2000 I have here. Roland made the osc and filter circuits on separate PCBs. In that case, I could build a PSU and a box to socket out the audio and CVs, and there we go, an module.

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Re: Transplanting synthesizer parts

Post by Bingo » Fri Jun 12, 2020 7:13 pm

Thank you very much for your reply. What you suggest about having a direct VCO out is very attractive. I've done that before. I once had an Axxe that had a dead filter. So I took a clip straight from the saw / pulse on the PCB and clipped it straight to the output and had a very wonderful, clean free-running VCO that was controlled by the keyboard and implemented features only present up to that part of the circuit (it came before the filter and A/R ADSR, I'm going to go ahead and assume all analog synths are wired like that).

Would you happen to know how modulation is integrated into a synthesize like the Cat? I can understand running a VCO through an external filter. I did it just last night running my SY-1 out into a Cat filter in, and I was able to obtain basically a new synthesizer sound I hadn't heard before. Don't know why after all these years I didn't think to try it!

But now what if I want to take the Vco out and run it into the Cat's ADSR, or the Cat's modulation? I'm not about to start cuting up PCBs today, I'm mostly just curious about some of the thought behind how these machines work. Thanks for your consideration.

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Re: Transplanting synthesizer parts

Post by madtheory » Sat Jun 13, 2020 11:21 am

You'd need to look at the service manual and schematics, to see where you can "clip out" the signals you want. You will probably want to think about buffering outputs that don't have buffers where you are "clipping out" from. Likely someone has figured this out for the Axxe already, so you may want to look in to modifications kits as I already suggested.

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