seven-hundred progress

System 700 LFO clone and a messy desk

Still going, just about. Not sure what I’m doing with that speed switch yet, whether to go faster or slower, hmm.

While I scratch my chin about how to reinforce these daft plastic panels, I’ve been enjoying reading through Fumitaka Ansai’s page on the System 700 – http://anz.yokohama/Museum/Roland/System-700/.

Assuming that Google Translate is accurate (my obsession with the System 700 isn’t quite going to stretch to learning Japanese) it’s interesting to find out that the original prototype had internal speakers, like the ARP2600! Also, it seems that users had been asking for a voltage-controlled envelope generator so they’d planned to release one but never got round to it, even in the later 100M.

I wonder if it was designed and never released? The owners manual for the 700 lists the modules, with gaps at 719, 722, and then 724 – 728, almost as if they intended to fill those gaps at some stage. Actually, maybe the prototype speakers were numbered 719.

Anyway, there are some fun demos on the anz.yokohama site too – if you have a look at the patch samples and then scroll down to Sample Chart 5, you can hear a nice example of using a voice to control a squealing oscillator with the 714 Interface. I’m half-tempted to build that one but it’s a big board, and I’m not sure if I’d just spend ten minutes laughing into it and then never touching it after.

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703e VCF with LM13700s

Someone asked on electro-music about subbing a LM13700 for a couple of CA3080s in a Roland-style filter, so I thought I’d have a go. I levered out the 3080s in my 703e clone and wired up three LM13700s (two for the four poles, one-half for the resonance control) and to no-one’s great surprise, it works.

Here is some quick fiddling with an out-of-tune clone 700 oscillator into the 703e VCF.

It sounds a bit overdriven to me – I was trying to avoid any red lights, but being in a hurry to get something down it’s possible I got something wrong along the way.

Now I think about it, it could be that I didn’t recalibrate the DC offset trimmers from when it was set up with the 3080s.

The wires strewn all over the board probably aren’t helping either, so I’m tempted to build up another 703e and make some LM13700-to-CA3080 adaptors to test this further.

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i’d rather multiple jack

710 multiple clone

OK I know, but it’s a start.

3mm acrylic is bendy, so I reinforced the back with 1.5mm aluminium to make it much stiffer, but it’s still not as solid as I’d like it.

Clone System 700 multiple from the back, showing the metal reinforcement

I should have really made the metal plate wider than I needed on one side, and bent it up to form an L-shape to totally stop the bending.

No chance for recessed jack sockets like on the original, my metal working just isn’t that good. 4.5mm panel depth is really the limit for these jack sockets, and it’s borderline for rotary pots.

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