[sdiy] Legal issues of cloning

[Tom Wiltshire]

I agree with the broad point that you're making, David. But the two instruments aren't comparable. The Jupiter 8 is significantly later and benefits from the application of microprocessors. I believe I'm correct in saying that the CS80 doesn't have a uP inside. That accounts for a lot of the complexity and a significant amount of the wiring. It'd be possible to build a "functional" clone with a lot less wiring (e.g. a clone of the functionality, not the actual circuit or PCB layout). It'd probably be possible to reduce the circuitry of the Jupiter 8 to some extent too. Many synths from that era use (for example) external memory and external UARTs which would all be found on a modern uP.

Some people are more purist about it and like to go as far as copying the old PCBs, but for me, if it does the same, it is the same. I don't much care what's inside beyond getting it to sound right, and where voice assignment, memory, and MIDI handling are concerned, that isn't an issue.

I also agree with Colin. These things aren't cheap to do, even given these simplifications, although the hardware (keyboard, case, controls) is a major part of that and if you're willing to do more of that yourself there are savings to be had. 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. If you add that in, £5000 starts to seem like the quickest and cheapest way.

2 cents,
Tom


On 6 Oct 2013, at 19:08, David G Dixon <dixon at mail.ubc.ca> wrote:

> I've never looked under the hood of a Jupiter-8, but I have looked under the
> hood of a CS-80.  Assuming they are similar, by the time you have figured
> out how to get all that stuff working together and stuffed into the
> enclosure, your wife will probably have wished you had just spent the money
> on a real one.  There is like 50 lbs of just wire in that thing!
> 
>> Ok I see your point on production building, but in terms of 
>> building just for myself I've picked up two 2 43-key keybeds 
>> for £10. Front panel controls are an issue, but buying in 
>> bulk, potentiometers should be around £50. The case can be 
>> built from wood by me, not sure of the cost of that. Reichelt 
>> sells the correct coloured switches with the led mounted at 
>> the top. ok around £100 squids for all of that. Then the voices...
> 
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