Couldn't we just have a poll My suspicion is that the practical value of very good analogue sine waves will be high for only some. As Dieter posted, an earlier discussion then fizzled out and didn't result in any product modifications. Maybe the discussion has shown there there is indeed a lot of (commercially tangible) interest in an oscillator with a very good sine output. On the other hand, maybe the interest is more intellectual and doesn't incite people to actually part with their money and buy the new design. A poll could give us at least an indication. I suggest something like this
"Do you want Doepfer to modify the sine-converter in the A-111 to produce a purer sine wave The cost increase would be in the 5% - 10% range."
York
________________________________
From: Monroe Eskew <
monroe.eskew@...
>
To:
Doepfer_a100@yahoogroups.com
Sent: Tuesday, December 2, 2008 3:39:52 PM
Subject: Re: 1 Re: Sine wave discussion
Couldn't we just use a standard LPF for this
On Dec 2, 2008, at 11:46 AM, James Husted wrote:
> The part of this circuit that does the conversion seems pretty
> straight ahead and looks simple enough to make as a stan-alone module.
> If one was needing to make sines and had a triangle VCO already (that
> made a decent Triangle wave) then a converter module would work fine -
> a bit esoteric for mass production though.
> -James
>
> PS - sorry to all for starting this thread with my Z3000 post. I had
> my questions answered a long time ago.
>
> On Dec 2, 2008, at 10:38 AM, laryn91 wrote:
>
> > Sorry, I missed the "will" part :-p
> >
> > I had this link to the Aries VCO in one of the posts on this
> > (endless) thread. This is an
> > excellent tri-to-sine converter (I can't hear any additional
> > overtones). Better than the more
> > common 3080 converter and significantly better than your diode
> > converter. Aries claimed
> > to produce <1% THD.
> >
> >
http://www.leinerme
dia.net/aries/ AriesSchematics/ AR-317s.gif
> >
> > I'm not sure why you found adding a slightly filtered triangle
> > sounding wave useful when
> > there's already a triangle wave output. My suggestion is if your
> > customers are not
> > interested in a clean Sine output, use the panel real estate for
> > something more useful.
> >
> > --- In Doepfer_a100@ yahoogroups. com, <yahoo@...> wrote:
> > >
> > > You find my answers written inline.
> > >
> > > Best wishes
> > > Dieter Doepfer
> > >
> > > > -----Ursprüngliche Nachricht--- --
> > > > Von: Doepfer_a100@ yahoogroups. com
> > > > [mailto:Doepfer_a100@ yahoogroups. com]Im Auftrag von laryn91
> > > > Gesendet: Dienstag, 2. Dezember 2008 17:20
> > > > An: Doepfer_a100@ yahoogroups. com
> > > > Betreff: 1 Re: Sine wave discussion
> > > >
> > > >
> > > > > And we will point out in the module information and user's
> > guide of
> > > A-110
> > > > > and A-111 that the sine outputs should be called more
> precisely
> > > "sine-like".
> > > >
> > > > Dieter,
> > > >
> > > > It's probably just me, but where do you point that out for the
> > A-111
> > >
> > > I wrote that "we will", not that "we did". That's the future tense
> > from what
> > > I learned in scool - but I'm not a native speaker.
> > >
> > > > >If you want a perfect sine you need a VCO with a sine core.
> > > >
> > > > Instead of an impossible "perfect sine", how about just a sine
> > with no
> > > *audible* overtones
> > > > (<1% THD) like Arp, Moog, Aries, Polyfusion, EML,etc. used to
> > make That
> > > would now
> > > > make the A-111 useful for additive synthesis and FM.
> > > >
> > > > All you need to do is copy their simple but superior
> > > > triangle-to- sine converter design. ;-)
> > >
> > > Though I can't believe that they really reach <1% THD (but indeed
> > I never
> > > measured it): do you (or anybody else in the group) know the
> > circuitry of
> > > these converters. Are they made with diodes, OTAs or the JFET
> > circuit (these
> > > are the three triangle-to- sine converter principles I know). I
> > don't have
> > > the schematics of these VCOs.
> > >
> > > We would have offered a VCO with a more perfect sine in the past.
> > But it
> > > took more than 12 years (the A-111 is available since spring 1996)
> > until
> > > someone complained about the poor sine. I'll see what we can do.
> > Maybe we
> > > offer a small tri-to-sine converter board for the A-111-1 that can
> > be used
> > > instead of the simple diode converter.
> > >
> > > There was a similar discussion about 2 years ago (~ September
> > 2006) and Tim
> > > Stinchcombe suggested an improved sine wave converter based on the
> > JFET
> > > principle. We have built a prototype of this converter in 2006 but
> > the
> > > discussion fell asleep very soon and it seemed that nobody was
> > interested
> > > anymore. We could dig this design and offer it as an addendum to
> > the A-111-1
> > > or equip all new A-111-1 with this board. The additional charges
> > would be in
> > > the 15 Euro range (about 10 electronical parts mounted on a small
> > board).
> > >
> > > Best wishes
> > > Dieter Doepfer
> > >
> >
> >
> >
>
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>
>
>
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