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I've gone DIY again - Sparta Synthesizer
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Broadwave
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Joined: 25 May 2011
Posts: 1027
Location: Manchester UK

PostPosted: Sun Nov 13, 2016 2:20 pm    Post subject: I've gone DIY again - Sparta Synthesizer Reply with quote

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 Wink

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 Wink

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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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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voip
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PostPosted: Sun Nov 13, 2016 5:08 pm    Post subject: Reply with quote

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
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Joined: 25 May 2011
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Location: Manchester UK

PostPosted: Sun Nov 13, 2016 7:54 pm    Post subject: Reply with quote

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".
.


I've done quite a bit of custom work over the past 20 years... I thought it was time to build something for myself. Wink
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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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voip
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PostPosted: Tue Nov 15, 2016 10:26 pm    Post subject: Reply with quote

Good luck with the project. Looking forward to seeing the result.

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Weirdofromouterspace



Joined: 04 May 2015
Posts: 33
Location: Germany

PostPosted: Fri Nov 18, 2016 12:35 pm    Post subject: Reply with quote

That looks cool - like some 'Odyssey goes 2600' concept Wink.
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Broadwave
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PostPosted: Tue Nov 22, 2016 7:13 am    Post subject: Reply with quote

The panel has just arrived. It's ok - the digital print is a bit low rez, but good enough for a home brew Wink 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 Embarassed






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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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Akos Janca
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Joined: 16 Mar 2005
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PostPosted: Tue Nov 22, 2016 8:12 am    Post subject: Reply with quote

Thank you for sharing, I like this beautiful concept very much. Is it an Xkey Air?
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Broadwave
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PostPosted: Tue Nov 22, 2016 9:20 am    Post subject: Reply with quote

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 Wink
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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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Akos Janca
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Joined: 16 Mar 2005
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Location: Budapest, Hungary

PostPosted: Tue Nov 22, 2016 10:21 am    Post subject: Reply with quote

Thanks - I haven't tried the Xkey yet but I'm interested in buying some controller keyboard. I see that you will not attach it for good to the Sparta - good name by the way - but it fits perfectly.
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Broadwave
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PostPosted: Thu Dec 01, 2016 12:05 am    Post subject: Reply with quote

All the plug-in modules are done, just the main 3 carrier boards to do Wink

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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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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Broadwave
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PostPosted: Sun Dec 04, 2016 9:17 am    Post subject: Reply with quote

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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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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Broadwave
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PostPosted: Sat Dec 10, 2016 4:02 pm    Post subject: Reply with quote

All the modules are fitted and working Wink

Just waiting for a few quotes for a basic bent aluminium chassis, then I can get on and assemble everything.


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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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Broadwave
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PostPosted: Thu Dec 15, 2016 3:36 pm    Post subject: Reply with quote

Everything is working except for the Mod/Aftertouch routing. Looks like I'll have to resort to some CMOS switching Rolling Eyes

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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Kronos 2 88, Roland System-8, Novation Ultranova, ARP Odyssey, Broadwave ARP 2600EX, Broadwave Sparta, Broadwave/Behringer Minimoog Clone, Broadwave Modular, Fender Deluxe Plus Top (iOS), Broadwave 12 String Telecaster

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Escapegoat



Joined: 07 Jun 2016
Posts: 23
Location: Cambridge, UK

PostPosted: Thu Dec 15, 2016 4:22 pm    Post subject: Reply with quote

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
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Joined: 16 Mar 2005
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PostPosted: Fri Dec 16, 2016 10:19 am    Post subject: Reply with quote

Thank you again, it's good to see this. I will be interested in the sound.
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