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