[sdiy] Prophet 08 sub oscillator mod?

[cheater cheater]

Sent :)
let's wait and see what happens...

On Sun, Jan 4, 2009 at 8:59 AM, Paul Maddox
<paul.maddox.mail-list at synth.net> wrote:
> D,
>
>  why not email him asking for it?
> he may include it in a future OS, or may tell you if it could be done
> easily.
>
> Paul
>
> On 3 Jan 2009, at 16:40, cheater cheater wrote:
>
>>> It's a tiresome way to recreate work that Dave Smith has already done.
>>> But
>>> you'd have a cool custom Prophet at the end of it...
>>
>> hehe, yes, well, it doesn't hurt to foray into dreamworld every now and
>> then.
>> As far as the sub octave goes: mopho does it; it's supposedly almost
>> the same thing as a single p08 voice; i don't see why it wouldn't be
>> possible with the p08 then; i don't suppose they had a special chip
>> made for the mopho.
>> Any idea how that monosynth does it?
>>
>> Cheers
>> D.
>>
>> On Sat, Jan 3, 2009 at 4:19 PM, Tom Wiltshire <tom at electricdruid.net>
>> wrote:
>>>
>>> On 3 Jan 2009, at 15:26, cheater cheater wrote:
>>>
>>>> Wow, synth porn.
>>>> At least you know how your enemy looks from the inside... or something.
>>>>
>>>> Tim:
>>>>>
>>>>> Adding the hardware to create sub-octaves: big job
>>>>
>>>> What are you basing this on? Is there a schematic you are following?
>>>> What would be involved?
>>>
>>> You need a minimum of a flip-flop per oscillator (at least 8 dual
>>> flip-flop
>>> chips - 4013 or similar). You also need a way back into the output VCA.
>>> This
>>> might be the more difficult part, since there is no guarantee that this
>>> input is available on a pin. It may be internal to the DSI voice chip
>>> (top
>>> of the photo). There's loads of sub-oscillator schematics available you
>>> could use; the SH101 has a nice one, or the Korg Poly6 is another
>>> example.
>>>
>>>>> Reverse engineering and reprogramming the operating system and adding
>>>>> the
>>>>> hardware to allow control of the suboctaves: HUGE job.
>>>>
>>>> Oh yes, definitely.
>>>> But on the other hand, we're talking about a simple uC program here.
>>>> This isn't a supercomputer. People have reverse engineered bigger
>>>> things; the problem is that ASM isn't as popular nowadays, so if you
>>>> run into trouble, you might be hard pressed to find someone who knows
>>>> what to do :)
>>>
>>> Reverse engineering will be made even harder by the fact that you won't
>>> be
>>> able to get even the assembled code out of the uPs. It'll be
>>> code-protected.
>>> So instead you've got to write code that will do the same job from
>>> scratch
>>> without knowing anything about the hardware beyond what you can see.
>>> It's a tiresome way to recreate work that Dave Smith has already done.
>>> But
>>> you'd have a cool custom Prophet at the end of it...
>>>
>>> T.
>>>
>>>
>>>
>>>
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