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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Sun Nov 13, 2016 2:20 pm Post subject: I've gone DIY again - Sparta Synthesizer |
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After the recent upset with both the Minilogue and KARP - I just wasn't happy with either - I've decided to get my soldering iron out, dust it down and plug it in
Welcome to the SPARTA project - based on the Oddy but with a few extras: rotary controls (easier to do, and cheaper), Normalized Patch Points, Plug-in analogue VCFs (ARP/Roland/Moog), 3rd VCO, aftertouch and a few other bits. I've cheated slightly by using the CME Xkey 37 It's an easy option with pressure sensitive Mod, Pitch Bend and aftertouch - No point in making life hard by tearing down and rebuilding a battered MIDI controller
The panel is on order from Front Panel Express, as they now do digital UV printing directly to the aluminum. All the modules (VCO/LFO/VCF etc) plug directly onto a main carrier board. Most of the PCBs are ready for etching, I've just got the keyboard side of things to do.
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voip Platinum Member
Joined: 27 Nov 2014 Posts: 3773
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Posted: Sun Nov 13, 2016 5:08 pm Post subject: |
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This seems very well though out and designed. Has much testing or prototyping been done, or is this an established design?
Edit - OK, done a little digging and notice that there are other designs around with a Broadwave "badge".
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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Sun Nov 13, 2016 7:54 pm Post subject: |
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voip wrote: | This seems very well though out and designed. Has much testing or prototyping been done, or is this an established design?
Edit - OK, done a little digging and notice that there are other designs around with a Broadwave "badge".
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I've done quite a bit of custom work over the past 20 years... I thought it was time to build something for myself. _________________ Synth DIY Projects |
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voip Platinum Member
Joined: 27 Nov 2014 Posts: 3773
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Posted: Tue Nov 15, 2016 10:26 pm Post subject: |
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Good luck with the project. Looking forward to seeing the result.
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Weirdofromouterspace
Joined: 04 May 2015 Posts: 33 Location: Germany
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Posted: Fri Nov 18, 2016 12:35 pm Post subject: |
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That looks cool - like some 'Odyssey goes 2600' concept . _________________ Korg: Poly-800 | microKORG | microSAMPLER | SQ-1 | Volca Beats | Volca Bass
Yamaha: DX7IID | DX21
Arturia: Minibrute
Kawai: K1
Roland: JX-03
DIY: MFOS Sound Lab Mini Synth Plus | MFOS Sound Lab Ultimate & Expander | MFOS 12-Band Vocoder | TTSH | Jasper | ARP 1601 Sequencer |
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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Tue Nov 22, 2016 7:13 am Post subject: |
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The panel has just arrived. It's ok - the digital print is a bit low rez, but good enough for a home brew Everything seems to line up, so I can finish the PCBs now - Very happy with the Xkey integration, it matches beautifully.
But... I forgot about the 3 mounting holes on each side
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Akos Janca Platinum Member
Joined: 16 Mar 2005 Posts: 1158 Location: Budapest, Hungary
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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Tue Nov 22, 2016 9:20 am Post subject: |
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Akos Janca wrote: | Thank you for sharing, I like this beautiful concept very much. Is it an Xkey Air? |
Thank you... No, it's just the standard version as I don't need wireless for this project. Getting used to the low profile key travel takes a while, but once you've got it, it's very responsive.
The only problem I have to deal with is the Pitch Bend... My MIDI to CV converts the bend to +/- 1volt and mixes it with the 1v/Oct CV - so I need to find a way of lowering the CME's Bend output... I'm hoping that it uses a standard Force Sensing Resistor, so I can use a couple of trimmers to get the output voltage down to a sensible level before the digital circuitry.
There's a few things I'd like to add (bend depth & velocity control for both the VCF & VCA) so I'll have to discreetly put them on the back panel - No doubt I'll think of a few other things too.
It's all part of the fun _________________ Synth DIY Projects |
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Akos Janca Platinum Member
Joined: 16 Mar 2005 Posts: 1158 Location: Budapest, Hungary
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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Thu Dec 01, 2016 12:05 am Post subject: |
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All the plug-in modules are done, just the main 3 carrier boards to do
The VCF modules will be accessible via the rear panel so they can be swapped out - I've currently got the ARP 4035 & 4075... Korg MS20 and Roland M121 on the way.
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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Sun Dec 04, 2016 9:17 am Post subject: |
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The 3 main carrier boards are now done... Just assembly and testing to do now. Fingers crossed the switches and pots line up to the panel.
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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Sat Dec 10, 2016 4:02 pm Post subject: |
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All the modules are fitted and working
Just waiting for a few quotes for a basic bent aluminium chassis, then I can get on and assemble everything.
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Broadwave Platinum Member
Joined: 25 May 2011 Posts: 1118 Location: Manchester UK
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Posted: Thu Dec 15, 2016 3:36 pm Post subject: |
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Everything is working except for the Mod/Aftertouch routing. Looks like I'll have to resort to some CMOS switching
The chassis has arrived, but the knobs are stuck at Heathrow - apart from that, it's sounding pretty good. Just a week or two and it'll be completed.
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Escapegoat
Joined: 07 Jun 2016 Posts: 23 Location: Cambridge, UK
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Posted: Thu Dec 15, 2016 4:22 pm Post subject: |
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Fantastic work. I'd love to build a desktop version if you decide to make boards/etc available?
Is there any crosstalk/oscillation issue when bringing so many signals to the patch panel? |
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Akos Janca Platinum Member
Joined: 16 Mar 2005 Posts: 1158 Location: Budapest, Hungary
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