[sdiy] Hadamard Transform Network

[Steve Lenham]

Hi Joel,

Agreed - without the DS-310, the keyboards themselves are very limited.

Frustratingly, the complete additive synthesis engine is in the main 
unit but cannot be programmed without the '310. The '310 is effectively 
a programmable ROM cart.

OTOH, once one has worked out the format of the patches then it should 
not be too difficult to design a DS-310 equivalent. I'm particularly 
interested to see whether the patch format offers possibilities beyond 
those that the DS-310 uses (e.g. fully variable envelopes rather than 
preset combinations, more/different harmonics, greater than 4-bit 
resolution for harmonic amplitudes).

I have two DS-202s (both recently brought back to life having been 
acquired faulty), one DS-310, one DS-320 sequencer (as yet untested, 
with horribly broken casework) and my newly-collected DS-250 with its 
ROM carts.

Will happily share my analysis once it is more complete. What I can say 
is that they are martyrs to dry/broken solder joints, because they use 
very large, single-sided SRBP PCBs. My DS-202s were riddled with bad 
joints and I expect that this problem will have decimated the number of 
units that has survived.

Also notable is that pretty much EVERY IC in the unit - and there are 
many - is manufactured by Toshiba, including the ASICs that handle the 
additive synthesis. In my experience that is very unusual - the Toshiba 
sales rep must have played a blinder! Or perhaps the companies were 
linked in some way.

Interested to hear about the planned computer control - do you have any 
links or references to that? There is very little info around on this 
range, mostly the same few facts regurgitated. If anyone has any real 
technical information then that would be the golden egg - anyone?

Cheers,

Steve L.


On 15/05/2017 10:04, Joel B wrote:
> I have a couple of these - but with the DS-310 additive synthesis
> module, otherwise it's just a preset keyboard with split & layering
> features.
>
> Pretty sure these things are FT or FFT based digital additives
> though, Supposedly there were plans to for a external computer
> control but that remains obscured in the mists of time... love to see
> any analysis of a unit if someone takes it apart!
>
> Joel
>
> Sent from my iPhone
>
>> On May 15, 2017, at 1:40 AM, Steve Lenham <steve at bendentech.co.uk>
>> wrote:
>>
>> Ooh - are you thinking of the Seiko DS-250?
>>
>> Looks like a cheap Casio, uses additive synthesis of some type,
>> played on parts of Rendezvous?
>>
>> As coincidence would have it, I collected a DS-250 on Saturday
>> night. I'm having a bit of a Seiko DS-xxx period - they are a
>> interesting technological cul-de-sac - and hope to write up what I
>> find one day.
>>
>> I had assumed that they just used sinewaves, but will have to take
>> a closer look now.
>>
>> In fact, if anyone else in the UK is interested in joining the dark
>> side then the same seller has a second unit for sale - see eBay
>> item #201923566255. She used to work in Seiko's watch division and
>> bought one for herself and one for her mother! They both have/had
>> some rare ROM carts and a not-very-desirable external sequencer
>> included too.
>>
>> Cheers,
>>
>> Steve L. Benden Sound Technology
>>
>>
>>> On 15/05/2017 09:05, Neil Johnson wrote: Look up Walsh Functions.
>>> I seem to recall some oddball synth from way back used them - I
>>> think JMJ played it on a number of tracks.
>>>
>>> Neil
>>>
>>>> On 14 May 2017 at 15:21, Elain Klopke
>>>> <functionofform at gmail.com> wrote: So I came across a print out
>>>> of Bernie Hutchins' "Application of a Real-Time Hadamard
>>>> Transform Network to Sound Synthesis" paper while I was
>>>> clearing out my storage locker last week. I know I didn't have
>>>> a clue what was being said in it back when I printed the thing
>>>> off and I'm glad to report that it actually makes sense now.
>>>>
>>>> My question is, have any of you played with this?
>>>>
>>>> here's a link to the paper for reference:
>>>> http://electronotes.netfirms.com/AES2.PDF
>>
>>
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