Synth-DIY Yahoo! Groups Archives

Thread

A-110-6 Voltage Controlled Phase Shift?

2017-02-14 by vytis.puronas@yahoo.com

Dear Dieter,

I know that the production design of the A-110-6 quadrature trapezoid VCO has probably been finalised, but hopefully this is something you would consider implementing? I was reading J. Donald Tillman's article on quadrature trapezoid VCO design:

http://www.till.com/articles/QuadTrapVCO/discussion.html

And discovered that it is possible to voltage control the phase shift? Would this be possible on the A-110-6? In my opinion it could become one of the most powerful features of this VCO.

Voltage Controlled Phase Shift

The quadrature trapezoid core also enables the implementation of voltage controlled phase shift over a multiple cycle range. I'll cover the details of this in a later article.

While the Yamaha DX7 synthesizer is well known for its use of FM Synthesis, it really works with phase modulation. (The phrase FM Synthesis is used as a generic term to describe both frequency and phase modulation.) So analog versions of many DX-7 algorithms are good applications for voltage controlled phase shift.

Audio rate phase modulation can produce some amazing glassy FM-like sounds without pitch drift. In eurorack Malekko Richter Oscillator II and Schippmann CS-8 Omega-Phi have phase modulation capabilities but since adopting a 100% Doepfer A-100 system I feel we are missing out on these sounds. At LFO rate we can achieve chorus / supersaw like sounds.

It is possible to approximate similar sounds via Lin FM on A-110-4, but the pitch drift makes it less suitable for pitch perfect musical applications. Here is an older demo of mine exploring audio rate phase modulation feature on the Richter Oscillator II:

https://soundcloud.com/sfx-lab/malekko-richter-oscillator-ii-phase-modulation-demo

Is this something you have considered or would consider implementing on the A-110-6 or as a follow up model?

Thank you very much! Really looking forward to exploring your new designs.

Best wishes,

Vytis Puronas

Re: A-110-6 Voltage Controlled Phase Shift?

2017-02-14 by ninonine@xs4all.nl

This sounds very interesting to say the least and if it is possible to implement this in the A-110-6 that would be great and probably worth the extra wait.

From several articles read it seems that Thru-Zero FM and Triangle modulation opens up major sound timbre possibilities and probably even better when done in the analog domain.

Hardware implementations of DX-7 algorithms sounds very interesting or Supersaw, originally from the JP8000 implemented with 7 detuned waveforms and a high pass filter, would probably be possible with several techniques combined.
For sure all very interesting developements to explore in the analog domain :)

p.s. a deeper analysis of the original supersaw "hardware" implementation can be found here: https://www.nada.kth.se/utbildning/grukth/exjobb/rapportlistor/2010/rapporter10/szabo_adam_10131.pdf (discussion @ page 31)

Re: [Doepfer_a100] A-110-6 Voltage Controlled Phase Shift?

2017-02-14 by Diego Ragnini

that sounds bloody cool indeed
thanks for sharing
Diego

Show quoted textHide quoted text

> Il giorno 14 feb 2017, alle ore 21:26, vytis.puronas@yahoo.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> ha scritto:
> 
> Dear Dieter,
> 
> 
> I know that the production design of the A-110-6 quadrature trapezoid VCO has probably been finalised, but hopefully this is something you would consider implementing? I was reading J. Donald Tillman's article on quadrature trapezoid VCO design:
> http://www.till.com/articles/QuadTrapVCO/discussion.html
> 
> And discovered that it is possible to voltage control the phase shift? Would this be possible on the A-110-6? In my opinion it could become one of the most powerful features of this VCO.
> 
> Voltage Controlled Phase Shift
> 
> The quadrature trapezoid core also enables the imple mentation of voltage controlled phase shift over a multiple cycle range.  I'll cover the details of this in a later article.
> 
> While the Yamaha DX7 synthesizer is well known for its use of FM Synthesis, it really works with phase modulation. (The phrase FM Synthesis is used as a generic term to describe both frequency and phase modulation.)  So analog versions of many DX-7 algorithms are good applications for voltage controlled phase shift.
> 
> 
> 
> 
> Audio rate phase modulation can produce some amazing glassy FM-like sounds without pitch drift. In eurorack Malekko Richter Oscillator II and Schippmann CS-8 Omega-Phi have phase modulation capabilities but since adopting a 100% Doepfer A-100 system I feel we are missing out on these sounds. At LFO rate we can achieve chorus / supersaw like sounds.
> 
> 
> 
> It is possible to approximate similar s ounds via Lin FM on A-110-4, but the pitch drift makes it less suitable for pitch perfect musical applications. Here is an older demo of mine exploring audio rate phase modulation feature on the Richter Oscillator II:
> 
> https://soundcloud.com/sfx-lab/malekko-richter-oscillator-ii-phase-modulation-demo
> 
> 
> 
> Is this something you have considered or would consider implementing on the A-110-6 or as a follow up model?
> 
> 
> 
> Thank you very much! Really looking forward to exploring your new designs.
> 
> 
> 
> Best wishes,
> 
> Vytis Puronas
> 
>

AW: [Doepfer_a100] A-110-6 Voltage Controlled Phase Shift?

2017-02-15 by yahoo@doepfer.de

Hello,

the A-110-6 design has been finished already and the module is already in
production. I hope it will be available about April 2017. Maybe it's
possible to realize the VC phase shifting as an additional module.

Best wishes
Dieter Doepfer

Show quoted textHide quoted text

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com [mailto:Doepfer_a100@yahoogroups.com]
> Gesendet: Dienstag, 14. Februar 2017 21:26
> An: Doepfer_a100@yahoogroups.com
> Betreff: [Doepfer_a100] A-110-6 Voltage Controlled Phase Shift?
>
>
>
>
> Dear Dieter,
>
>
> I know that the production design of the A-110-6 quadrature
> trapezoid VCO has probably been finalised, but hopefully this is
> something you would consider implementing? I was reading J.
> Donald Tillman's article on quadrature trapezoid VCO design:
> http://www.till.com/articles/QuadTrapVCO/discussion.html
>
>
>
> And discovered that it is possible to voltage control the phase
> shift? Would this be possible on the A-110-6? In my opinion it
> could become one of the most powerful features of this VCO.
>
>
> Voltage Controlled Phase Shift
> The quadrature trapezoid core also enables the implementation of
> voltage controlled phase shift over a multiple cycle range.  I'll
> cover the details of this in a later article.
> While the Yamaha DX7 synthesizer is well known for its use of FM
> Synthesis, it really works with phase modulation. (The phrase FM
> Synthesis is used as a generic term to describe both frequency
> and phase modulation.)  So analog versions of many DX-7
> algorithms are good applications for voltage controlled phase shift.
>
>
>
>
> Audio rate phase modulation can produce some amazing glassy
> FM-like sounds without pitch drift. In eurorack Malekko Richter
> Oscillator II and Schippmann CS-8 Omega-Phi have phase modulation
> capabilities but since adopting a 100% Doepfer A-100 system I
> feel we are missing out on these sounds. At LFO rate we can
> achieve chorus / supersaw like sounds.
>
>
> It is possible to approximate similar sounds via Lin FM on
> A-110-4, but the pitch drift makes it less suitable for pitch
> perfect musical applications. Here is an older demo of mine
> exploring audio rate phase modulation feature on the Richter
> Oscillator II:
> https://soundcloud.com/sfx-lab/malekko-richter-oscillator-ii-phase
> -modulation-demo
>
>
>
> Is this something you have considered or would consider
> implementing on the A-110-6 or as a follow up model?
>
>
> Thank you very much! Really looking forward to exploring your new designs.
>
>
> Best wishes,
> Vytis Puronas
>
>
>
>

Re: AW: [Doepfer_a100] A-110-6 Voltage Controlled Phase Shift?

2017-02-15 by ninonine@xs4all.nl

Would it make sense to utilize the A-143-9 (with navsmodularlab mod) or A-110-4 module(s) to accomplish (a form of) VC phase shifting. Or could this (also) be implemented in the future planned thru zero version of the A-111-2?

AW: AW: [Doepfer_a100] A-110-6 Voltage Controlled Phase Shift?

2017-02-15 by yahoo@doepfer.de

That's just a modification for linear FM and has nothing to do with VC phase
shifting. This feature cannot be obtained in such an easy way. By the way: a
module that generates VC phase shifting for sawtooth waves is the A-137-2.

Best wishes
Dieter Doepfer

Show quoted textHide quoted text

> Would it make sense to utilize the A-143-9 (with navsmodularlab
> mod) or A-110-4 module(s) to accomplish (a form of) VC phase
> shifting. Or could this (also) be implemented in the future
> planned thru zero version of the A-111-2?

Re: AW: AW: [Doepfer_a100] A-110-6 Voltage Controlled Phase Shift?

2017-02-15 by ninonine@xs4all.nl

Thanks for clarifying that out. I also like both the 137-2 and 137-1, they have nearly the same result in how i use them but with a different approach. Using 4 different (free running) vco/lfo signals from quad lfo/vco modules gives great results.