[sdiy] FW: Legal issues of cloning

[Jack Jackson]

RE:MT-32. Didn't Roland fail with that because they hadn't registered copyright for the MT-32 PCM samples?

I've already cloned the VCO, waveshaping circuits, noise generator and vca (using LM13700s) with currently available components. 

The filter seems like the hardest part yet. Even with the IR3109s, although I've got LPF, and to an extent HPF working. I haven't succeeded with resonance so far.

In terms of the patch memory, I'm looking forward to get cracking with that. My day job is programming so it's not too daunting. Tom Wiltshire has done a lot of really awesome stuff using PICs, so that is quite encouraging and inspiring. It seems the JP8 achieved all the analogue voltages out of the microprocessor using one DAC a SI/PO shift register and a load of opamps as voltage followers. If I understand correctly the microprocessor cycles through all the outputs of the shift register and feeds each opamp the relevant voltage in turn. In Ray Wilsons book he mentions that voltage followers can hold a state for a few seconds before the voltage begins to drop off, so I'm not sure at what rate the shift register clocks through all the opamps, but could be once per second to several times a second.

If you want to take a listen, I've put some recordings up:
https://soundcloud.com/dot

Here's the thread about it on MuffWiggler:
http://www.muffwiggler.com/forum/viewtopic.php?p=1286357&sid=13de13fb6f6838abb251dffa61ec546b





----------------------------------------
> Date: Sun, 6 Oct 2013 14:35:54 -0500
> From: commodorejohn at gmail.com
> To: tom at electricdruid.net
> CC: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] Legal issues of cloning
>
> On 10/6/13, Tom Wiltshire <tom at electricdruid.net> wrote:
>> Yes, you can probably build a Jupiter 8 for less than
>> £5000, but you won't be getting paid for any of the hundreds of hours you
>> spend programming the firmware for the thing.
> The firmware for something like the JP8 really shouldn't be that
> complicated, even with MIDI support added in. It's not even like my
> Matrix-6 where all the modulation is entirely digital and there's a
> complex virtual patch-matrix to set up. Of course, it's still *work,*
> but on the software side it should be entirely doable by one guy as a
> hobby project. (No idea about the hardware, though - but if Jack ever
> does come up with a solid Jupiter-8 clone, you can bet I'll be first
> in line!)
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