[sdiy] SH2000 mod (wavetables)

Tom Wiltshire tom at electricdruid.net
Wed May 27 10:16:35 CEST 2009


Looking at the service manual (http://manuals.fdiskc.com/flat/Roland% 
20SH-2000%20Service%20Manual.zip) it looks like Mark is right.

There's a 555-based oscillator, followed by the VG-7 "wave selector"  
which seems to be dividers and mixers to produce ramp waves and  
square/pulse waves at various octaves. Don't expect great waveform  
purity, and don't expect any non-octave footages.

Still, having access to the separate waveforms (nine of them!) would  
probably give you a lot more options.

Regards,
Tom

On 26 May 2009, at 22:29, mark verbos wrote:

>
>
> I believe the SH-2000 has a saw core and a circuit which makes  
> square waves at several octaves below, then adds them to the saw  
> wave to make saw waves over several octaves. A TOG would give all  
> the notes in an octave, not rather than several octaves. I could be  
> wrong.
>
> Mark
>
>
>
>
> On May 26, 2009, at 5:01 PM, Graham Atkins wrote:
>
>> Gil,
>>
>> On 26 May 2009, at 21:39, Gil W. wrote:
>>
>>>
>>> Well, any idea what mod the reviewer described here after all ?
>>
>> I am guessing that it may be using a top octave generator (T.O.G.)
>> like an organ, string synth etc. I think this would explain the word
>> "divider oscillator". I think the Korg used a T.O.G. as well. What  
>> this
>> sounds like is a mod to allow acess to the sounds at all of the
>> octaves that the master is divided down to, to allow more sounds.
>> Think of it like an organ adding extra drawbars to allow lower notes
>> to be mixed in the sound.
>>
>> Graham
>>
>>
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