- In a message dated 9/30/2004 8:14:29 PM Eastern Daylight Time, email@example.com ... chris, no - they just provided normal linear fm. only one commercial thru zeroMessage 1 of 15 , Sep 30, 2004View SourceIn a message dated 9/30/2004 8:14:29 PM Eastern Daylight Time, cbm@...
> Weren't the VCOs on the original EMu modular through-zero?chris,
no - they just provided normal linear fm.
only one commercial thru zero vcf had been previously advertised, to the best
of my knowledge, and that being one from dennis electronics back in the
late 70`s and not widely distributed. denny genovese also designed and sold a
neat c.v. processor and has been extensively involved in microtonality. on the
vco`s, if i remember correctly, i was told that one of the guys in tangerine
dream insisted on buying and taking the earliest demo units.
[Non-text portions of this message have been removed]
- Just as a matter of interest, the CEM3340 can be adapted to through zero linear FM operation, see this link to Jurgen Haible s dual VCO design.Message 2 of 15 , Oct 1, 2004View SourceJust as a matter of interest, the CEM3340 can be adapted to through
zero linear FM operation, see this link to Jurgen Haible's dual VCO
--- In Doepfer_a100@yahoogroups.com, "Tim Stinchcombe"
> Hi Florian, Matthew,I
> > > > Here is a little something on the topic of thru-zero FM.
> > > > http://www.uni-bonn.de/~uzs159/vco6.html
> > > This looks like the Curtis CEM 3340 is a thru-zero VCO too. Am
> > > wrong or right?110
> Unfortunately it is not. Oscillators like the CEM3340 and the A-
> require a 'standing current', positive for the 3340, negative forthe
> A-110. For normal 1V/octave (exponential) use this is constant,and
> passes through an exponential converter (controlled by the freqCV)
> and thence charges a capacitor. The capacitor is dischargedsuddenly
> in the A-110, hence it's a sawtooth core; in the CEM3340, currentas
> mirrors reverse the current and discharge the cap at the same rate
> it was charged, hence a triangle core. For linear FM control ofboth
> of these, the linear FM input simply adds or subtracts currentfrom
> the standing current, by an amount linearly proportional to theto
> applied voltage: if this voltage becomes of such a size so as to
> reduce the (magnitude of the) standing current to zero, the
> oscillator simply stops, as there is nothing to charge the cap! To
> prevent this happening generally requires quite a lot of trickery
> reverse everything at the appropriate moment, hence all theswitches
> and comparator in the Schmitz design.and
> Yet another thing on my list to look at once I finish my studies
> have the time!