New DIY Build - "Sparta" Semi Modular Analogue Synth

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Broadwave
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Re: New DIY Build - Semi Modular Analogue Synth

Post by Broadwave » Fri Jan 06, 2017 10:42 am

sw_hunt wrote:Very professional design work :)
Can you please tell me what PCBCAD software you're using and what you use for designing the front panel?
Many thanks
Thank you - There's no PCB CAD :shock: It's all drawn freehand directly from schematics, I use Autodesk Graphic vector software (OSX). I've tried things like Eagle and Pad to Pad, but never been happy with the AutoRouting.

The panel is from Front Panel Express - I just use the supplied software from their web site to handle the drilling and Imported artwork.

Unfortunately, I've just blown the V2164 Quad VCA on the Aftertouch/Mod PCB :roll: - So I'll have to wait a day or two for some spares. Luckily, Thonk here in the UK have them in stock. Apparently you have to be very careful how you power up the V2164 - I accidentally plugged the board in with the power still on which was enough to blow it, so I'll add a couple of protection diodes just to be safe.

It's all been frustratingly slow, but at least I've had time to tidy up the patch point birds nest with minimal crosstalk ;)

Image

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Re: New DIY Build - Semi Modular Analogue Synth

Post by sw_hunt » Fri Jan 06, 2017 11:56 am

wow you've got a steady hand! All the PCBs were drawn with a black pen? You've posted some images of the layouts - does this mean you drew on acetate or something and then UV exposed the copper from those? It's a long time since I made PCBs - I drew directy on copper - but I'm starting to get inspired to do something again!

Are your scematics available somewhere or could you share them with a discerning few?

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Re: New DIY Build - Semi Modular Analogue Synth

Post by Weirdofromouterspace » Fri Jan 06, 2017 12:06 pm

Broadwave wrote:It's all drawn freehand directly from schematics
I don't use these very often, but you deserve it: Image Image Image Image
Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason why you get no sound out of it. - ARP 2600 manual, 1971

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Re: New DIY Build - Semi Modular Analogue Synth

Post by Broadwave » Fri Jan 06, 2017 4:15 pm

sw_hunt wrote:All the PCBs were drawn with a black pen?
No, no - I'm not THAT good ;) It's drawn with vector graphics software (click 'n drag to create a line, join them up, round off the corners and lay down pads - still pretty intensive stuff though). It's then printed onto acetate with an old laser printer and UV exposed to create the PCB.

I'll start uploading diagrams as soon as everything is together - I'll start with the Odyssey based VCOs (very small footprint, totally discreet components, very stable and no transistor matching required)

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Re: New DIY Build - Semi Modular Analogue Synth

Post by sw_hunt » Fri Jan 06, 2017 4:48 pm

Broadwave wrote:
sw_hunt wrote:All the PCBs were drawn with a black pen?

I'll start uploading diagrams as soon as everything is together - I'll start with the Odyssey based VCOs (very small footprint, totally discreet components, very stable and no transistor matching required)
Thanks I'd appreciate that :) I'm about to do a project with my son who wants to build a monosynth from scratch including PCB layout! Planning to use ExpressPCB for the design and need to buy a laser printer and UV box... I'm also considering a somewhat larger and crazier project to build a polysynth with a lot of unusual swept FM going on. Currently researching filters with VC resonance and ADSRs with VC'd A, D, S and R. Need everything voltage controlled as I want to use voltages to control the voice modules rather than multiplex the panel pots. Makes presets easier too. My stumbling block at the moment is finding a midi-CV converter that can generate 8 CV channels, or a 4-ch design that can overflow to a second unit.

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Re: New DIY Build - Semi Modular Analogue Synth

Post by Broadwave » Fri Jan 06, 2017 8:00 pm

sw_hunt wrote:My stumbling block at the moment is finding a midi-CV converter that can generate 8 CV channels, or a 4-ch design that can overflow to a second unit.
I'm using Hexinverter's MIDI2CV - 4 channels that can overflow to 8 ;)

You can either buy it Ready built or just the PCB's & PIC

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Re: New DIY Build - Semi Modular Analogue Synth

Post by sw_hunt » Fri Jan 06, 2017 10:11 pm

Excellent thanks - I'd looked at the manual but missed the bit about overflowing - cheers

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Re: New DIY Build - Semi Modular Analogue Synth

Post by Broadwave » Tue Jan 31, 2017 11:39 am

Finally... Properly completed. 7 week build, which is pretty fast for me.

Leather side panels on, rear I/O panel sorted (although due to a silly mistake I made in the artwork, it's white not, anodised - I'll get it re-done at a later date). Calibrated, re-calibrated & re-re-calibrated. It's all behaving perfectly ;)

I ditched the idea of plug-in VCFs for the time being, but it does have both ARP 4023 & 4035 VCFs inside which I can select with a switch.


I'll get a demo up as soon as I can.

Dual VCF Module
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Re: New DIY Build - "Sparta" Semi Modular Analogue Synth

Post by alan partridge » Tue Jan 31, 2017 12:06 pm

great work !

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Re: New DIY Build - "Sparta" Semi Modular Analogue Synth

Post by Yekuku » Tue Jan 31, 2017 1:31 pm

Your work is an inspiration for most of us, thanks for sharing :)
Have you implemented polyphonic aftertouch ? Can we have some insights ?
But why Sparta ? Shouldn't this be called Telemachos ? (...according to Greek History :p )
It is all about sharing...

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Re: New DIY Build - "Sparta" Semi Modular Analogue Synth

Post by Jabberwalky » Tue Jan 31, 2017 2:50 pm

Awesome! Aside from the papyrus font :( :wink:

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Re: New DIY Build - "Sparta" Semi Modular Analogue Synth

Post by commodorejohn » Tue Jan 31, 2017 4:12 pm

My oh my is that a beauty :D
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Re: New DIY Build - "Sparta" Semi Modular Analogue Synth

Post by Broadwave » Wed Feb 01, 2017 12:06 am

Jabberwalky wrote:Awesome! Aside from the papyrus font :( :wink:
You're lucky I didn't do a Roland tribute synth with Data 70 ;)

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Re: New DIY Build - "Sparta" Semi Modular Analogue Synth

Post by Stab Frenzy » Wed Feb 01, 2017 7:14 am

Regarding the 2164 failure, here's the mod to do to stop it happening again. It just requires a single diode.

http://electronic-sea.net/SSM2164.html

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Re: New DIY Build - "Sparta" Semi Modular Analogue Synth

Post by Broadwave » Wed Feb 01, 2017 9:11 am

Stab Frenzy wrote:Regarding the 2164 failure, here's the mod to do to stop it happening again. It just requires a single diode.
Ahhh... Thank you. That explains so much. I bought a bunch of them as backups in case it happened again - They're quite a useful chip to have around. More VCA's for the modular then ;)

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