Rebuild a 4700

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Rebuild a 4700

Post by Dlykin77 »

I am looking to purchase a (to the best of my knowledge) vintage 4700. I've been to the site and seen the new modules. Are these modules plug and play with an older synth like I'm looking at? I've seen videos where a 4700 and eurorack system are used together. Has anyone had any experience doing variations/mods like this?

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Re: Rebuild a 4700

Post by Kyhotay »

I completely rebuilt my 4700. Mainly I created new front panels, recapped, replaced switches & pots. Changed all jacks to 1/8" and upgraded critical op amps to Burr Brown. I frankensteined a 9700 regulated 15VDC power supply to do +/-9V and added regulated +18VDC.

The key thing to know is the 4720 VCO is Hz/V, not 1V/Oct like the new 9720 (same with the 4730 vs 9730). There is a exponential converter in the 9700 series but I think it's difficult to get it to track properly. There are a few (very few) Hz/V MIDI converters. The easiest solution is to run the CV and Gate out from a FatMan to the 4700. I use that all the time. In fact I built a panel for it. I can also interface my 4700 to my Korg Mini MS-20 and it works great. The only thing to keep in mind that the MS-20 uses the S-Trigger gate so you have to build a cable or use the 2720-12 inverter to trigger the envelopes.

The 4700 and 9700 modules won't fit in the same case and the power requirements are different.

I hope that helps.
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