I cant answer on the DC thump issue as I dont have an SDSV
it may be a faulty component in the unit he owns. As to the
filter, the internal circuitry of the 2044 is in fact very
similar to the SSM2040 and the CEM range of filters. There
have been a number of "replication circuits" published for
these, many of them based on OTA's either CA3080, LM13600
or LM13700. With the correct tweaking the sound from these
can be be adjusted to be so close to the original it would
hard for the normal ear to hear any difference. Keep in mind
that the SDS3 used a moog type 24db ladder filter and the only
reason simmons would have used the SSM2044 was it was cheaper
and used less PCB realestate. Same point about the way the SDSV
had a tone/click balance pot instead of 2 separate level pots.
It kept down the cost and used less room on the front panel.
My vision is to recreate a "modernised" version of the SDSV
as I'm sure simmons would do if they were around today.
The ability to more finely tune the various parameters and save
their settings would only enhance its usability. The actual sound
should remain the same.
Anyway as said in my first post, if someone can provide me with
some detailed photos of the SDSV and analog claptrap It would
be very much appreciated and all info will be shared with the
community. I am a semi retired electronics engineer (do to a
back injury) and projects like this stop me going brain dead..lol
--- In Simmons_Drums@yahoogroups.com, "WT" <waveterm@...> wrote:
>
>
> ----- Original Message -----
> From: "EPPHERRE" <raymond.eppherre@...>
> To: <Simmons_Drums@yahoogroups.com>
> Sent: Monday, November 23, 2009 4:55 PM
> Subject: [Simmons Drums] Re: Help required - in other words big ask ahead
>
>
> > Hello,
> > Me two I want to build my own SDS5 analog drum synth....I had a SDS5 brain
> > from ebay 4 years ago and I have redraw schematics from this unit...I have
> > noticed errors on the SIMMONS schematics....
> > I think we have to replace the SSM2044 by a discrete filter (like for
> > example on the Tama Techstar with LM13700 otas) and redesign the
> > enveloppes generators to have a cleaner triggering.I think also to replace
> > the Click/Drum balance control by a Click level control (like
> > SDS8,Techstar...)
>
>
> But but......then it´s no SDS-V
>
> > On my SDS5 I noticed a big DC thump at the output of the SSM2044 filter
> > when applying filter sweep and I don't like it(neither the speakers!)so
> > removing the SSM2044 that filter only noise and replacing with discrete
> > cheap filter will be the better solution.
>
> Is not the amplifier DC-coupled ?
>
> WT
>