Hi Florian, thank you very much for the patience, the support is much appreciated!

My issue to grasp depends on different 'subjective' factors among which prevails the lack of electronics basic principles. :-)

Then I got confused because in one of the previous messages of yours, before mentioning the 2 possibilities for using Vel and EG, you patiently tried to follow my proposal of mixing Vel+EG, but the core phrase you wrote missed the essential “verb” and so I still don't know exactly what really would entail mixing Vel+EG:

«if you mix the velocity voltage with the envelope voltage and feed the sum into one VCA, it will cause the VCA all the time a little bit (according to the velocity voltage) and the evnelope will add on top of this basic level.»

Anyway, now I see I always need to adopt 2 VCAs, probably (I try to guess again) the better quality VCA will preferably manage the audio signal (and here I can choose to fire the velocity OR the EG).

Another subject which probably crosses this application is the difference between linear and exp VCA. Sorry, I won't you to go back to the lin/exp dilemma of the EG segments :-) but if EGs segments are always exp (because it's easier to design), then probably wouldn't be that wise to have an amp which features exp control scales, it might be redundant. It seems that linear VCAs finally are more versatile...

As for the AC-coupled / DC-coupled thing, I really understood very little when I tried to go wiki. I only got that there are advantages and disadvantages in both ways of coupling. I just acritically rely on the assumption that a vca having DC-coupled ins/outs is suitable for better processing both audio and voltage signals, and that is also preferable that voltage signals are processed by linear VCAs. Don't know if there's a relationship between AC or DC coupling and Exp or Lin response, probably not at all..

One last thing: why do we found some VCA's who offer 2 CV Ins if they cannot be used to process EG + Velocity Do the 2 inputs affect the amp in the same way or they are wired to different stages

I was interested in this quad VCA, what do you think about it

https://www.modulargrid.net/e/doepfer-a-132-4

Thanks a lot !

Best regards,
Diego



----- Mail original -----
De: "Florian Anwander fanwander@... [Doepfer_a100]" < Doepfer_a100@yahoogroups.com >
À: "Doepfer a100" < Doepfer_a100@yahoogroups.com >
Envoyé: Dimanche 27 Novembre 2016 19:57:27
Objet: Re: 1 A-14x EG segment slopes

On 26.11.16 19:09 , diegora@... 1 wrote:


though I still believe that it would be necessary to adopt a VCA with «two» cv inputs, that is to have two control voltage inputs on the VCA module in order to modulate the amplitude through both EG and velocity voltages. Or there's a step I missed in the understanding of the patch Maybe you just intended to mix the two signals...
You still miss something. You always MUST have two VCAs to use velocity on the signal level. It does not matter, whether the velocity controlled VCA works DC coupled and manages the level of the envelope or whether it works AC coupled and manages the level of the audiosignal.

You may have a look at
http://www.doepfer.de/a100_man/A132_man.pdf
page 4, left example

Florian