I agree with you, that there is not anything special about the character of
the filter, it sounds good but also very neutral. I´ve become convinced that
the warmth and "crisp" is because of the valves. So the strength with the
product, aside from the valves, is the midi-control and the soft switching.
Although I´m a big fan of the VF-1, I also want to warn you about it. The
sound gets so much more aggressive in 24dB/mono-mode that you need another
unit to preserve the stereo. This makes the cost for the machine about the
same that would do for a rack full of modular. So the choice for anyone
who´s looking for real quality and character is very obvious...

/M

>From: "Dieter Doepfer" < hardware@... >
>Reply-To: Doepfer_a100@yahoogroups.com
>To: < Doepfer_a100@yahoogroups.com >
>Subject: AW: 1 Re: technichals...
>Date: Mon, 3 Apr 2006 12:36:14 +0200
>
>In principle each (or at least most) VCA can be used for a lot of voltage
>controlles applications (filters, phasers, oscillators, VCADSR's, and many
>more). As the SSM2164 has current outputs it is very easy to built a filter
>(e.g. state variable or 24dB LP) around the SSM2164 by adding a capacitor
>(or a capacitor in the feedback loop of an OpAmp) to each output. There are
>a lot of filter applications around the SSM2164 available in the internet.
>Try e.g. "SSM2164 filter" in Google and you will find a lot of examples. We
>also developed a SSM2164 based filter about 2-3 years ago (during the A-107
>design where we use the SSM2164 as a quad VCA) but never published this
>information as we could not find anything special in this filter (and we
>already have so many filters available).
>
>Best regards
>Dieter Doepfer
>Doepfer Musikelektronik GmbH
>Email address: hardware@...
>Web Site: www.doepfer.com
>
>
>
> > -----Ursprüngliche Nachricht-----
> > Von: Doepfer_a100@yahoogroups.com
> > [mailto: Doepfer_a100@yahoogroups.com ]Im Auftrag von Martin Rudling
> > Gesendet: Montag, 3. April 2006 10:31
> > An: Doepfer_a100@yahoogroups.com
> > Betreff: RE: 1 Re: technichals...
> >
> >
> > Thanks!
> >
> > It´s a bit funny, I think, that they (A&H) have chosen such an atypical
>chip
> > for filtering. I have been reading the info at "analog devices" and this
> > application is just mentioned very briefly. Anyhow, it sounds great as a
> > filter, but provides no selfoscillation. But I´m doing fine without.
> > Maybe my selling of the Mutronics-LP-filter and Analogue
> > Systems FB3, can
> > say something about the quality. I´m actually gonna use the money to buy
> > another VF-1, to get 24dB in stereo. But this choice is very much
>because
> > I´m lazy, and I find the manner of speaking "less is more" to be
> > very true
> > regarding audio-machines, but that´s me...
> > If the Mutator had been multimode I´d keep it, but LP only just
> > makes me
> > frustrated while tweaking. And of course the VF1 valves and the midi
> > (without passing a MCV interface) is attractive to the restless
> > personality.
> > I´m sending the Kenton M-CV to a modularist in the south of Sweden
>today.
> > The only thing I still have pure analogue is the AnaSys filterbank. I´ve
> > changed my mind on that one to, I´m selling it. Same price: 2500
> > SEK, that
> > should be 270 EUR. I have one adjustment to offer you, though..: I´ll
>pay
> > the shipping for you! (Europe)
> >
> > Best regards
> > /Martin
> >
> >
> >
> >
> >
> > >From: "selfoscillate" < synaptic_music@... >
> > >Reply-To: Doepfer_a100@yahoogroups.com
> > >To: Doepfer_a100@yahoogroups.com
> > >Subject: 1 Re: technichals...
> > >Date: Mon, 03 Apr 2006 05:56:12 -0000
> > >
> > >
> > >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: 1 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...
> > > > > >
> > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
>