[sdiy] OTA performance (was SSM chip reissue)

[john slee]

Since the OB-X was mentioned...

Maybe I missed something, but AFAIK Oldcrow used LM13700s in his crOwBX
voice cards.  I did a bit of quick google searching, and also read through
his calibration docs, and my very amateur eyes didn't spot anything that
jumped out at me as implying characterising LM13700s.

Surely this (VCF performance in the OB-X) is an example of a claim that can
be assessed by comparing the performance of Oldcrow's and Oberheim's
voicecards?

John


On 26 April 2017 at 16:44, Gordonjcp <gordonjcp at gjcp.net> wrote:

> On Wed, Apr 26, 2017 at 01:33:55PM +1000, Paul Perry wrote:
> > It would be a wonderful thing, if Oberheim had somebody deliberately
> > unmatching OTAs..
> >
>
> Probably a big tin bucket on the floor, where the "not good enough for the
> filter" ones get flung :-)
>
> > Seriously though, I very much appreciate your comments
> > on this.. I suspect that a lot of unhappiness in my life
> > was due to unmatched LM13700 halves.
>
> They'd have to be horribly unmatched to make something properly Not Work.
>
> I don't get why people are matching OTAs in the first place.  You need to
> have some adjustment over range and offset for the VCF to compensate for
> all the other tolerances, and you won't hear a mismatch between VCAs unless
> it's grossly out to the point of being faulty.
>
> --
> Gordonjcp MM0YEQ
>
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