Doepfer

hello martin,

over the weekend i checked my technical
documents about the ssm2164 again.
this chip can be found in several modules.
for example, blacet uses it a lot. usually
the ic itself is not configured to work as
a filter, but it can be found in vcf's
as a support chip to make parameters
voltage-controllable or for mixing of
filter stages (like in the a107).

as others pointed out, the ssm2164 can of
course be used as a filter circuit, but
that doesn't seem to be the typical purpose.
the only module i found where the ssm2164
is also configured as a filter is the blacet
improbability drive, but this module cannot
be used for filtering of a given signal,
as there is no filter input jack available.
so i cannot say anything about it's sound
as a filter. all i can say is that the ssm2164
is doing a great job as vca, but thats obvious.

best wishes

ingo



--- In Doepfer_a100@yahoogroups.com, "Martin Rudling" 
<martinrudling@...> wrote:
>
> Ooops sorry I hit the send button by mistake...
> 
> Well I´ll use the opportunity to thank you all for your input!!
> 
> Thanks!
> 
> And also I would like to encourage those who are having thoughts of 
adding 
> some valves to your modular. It´s ssooo nice!! Fat, creamy, 
organic, hot and 
> you name it...
> 
> It seems like the mutator is sold today, to a friend of mine. And I 
have 
> found a second FB3 for sale in England, so I think I´ll buy it, to 
go 
> stereo, which means that my unit is no longer for sale.
> 
> m
> 
> 
> 
> 
> >From: "Tim Stinchcombe" <timothy@...>
> >Reply-To: Doepfer_a100@yahoogroups.com
> >To: Doepfer_a100@yahoogroups.com
> >Subject: [Doepfer_a100] Re: technichals...
> >Date: Thu, 30 Mar 2006 20:44:52 -0000
> >
> >Hi Martin,
> >
> >The SSM2164 is made by Analogue Devices:
> >
> >http://www.analog.com/UploadedFiles/Data_Sheets/15183786ssm2164.pdf
> >
> >which with the right know-how can be turned into a 4-pole 24dB
> >filter, or from what Allen Heath have at their website for thr VF-
1,
> >2 x 2-pole state-variable filters (so basically 12dB each), which
> >thus give low-, high- and band-pass, and which if run one after the
> >other gives 24dB (hence the 'mono' switch on the back).
> >
> >I suspect a lot of the quality of the sound comes from the
> >overdrive/clipping introduced by the valve input section, but 
that's
> >only a guess - the total sound will depend on both chip and valves,
> >but how much it would change, say, if the valves were replaced by
> >transistors would probably be difficult to guess without trying it!
> >
> >Tim
> >
> > > I´ve asked Allen & Heath tech support what chips they used for 
the
> >VF-!
> > > analogue valve stereo-filter. I didn´t get much wiser from the
> >answer
> > > though.
> > > Maybe some one here knows about the chip SSM2164?
> > >
> > > (As you will see this is cuts from 2 different e-mails)
> > >
> > > >>>The active circuitry in the VF-1 is based on the SSM2163 Quad
> >VCA IC in
> > > an analogue filter configuration, supported by standard TL072 
op-
> >amps
> > > and of course a pair of ECC82 valves.
> > > >Thanks for your reply. Please note the typo in my last reply 
and
> >the fact
> > > >that it is the SSM2164, not 2163 IC that is the active VCA.>>>
> > >
> > > I´m curious, cuz I really love the sound of this machine, and I
> >wonder how
> > > much of this amusement is due the valve/overdrive section...
> > >
> > >
> > > >
> > >
> >
> >
> >
> >
> >
>