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A101-2 in VCA mode

2013-11-02 by nicholas.buckley@ntlworld.com

Hi everyone,

I'm preplanning my first A-100 purchases and I expect the A101-2 to be included.
When this module is operating in VCA mode, is the response Linear ( as in A-130 ) or exponential ( as in A-131 ) ?

The reason for asking is that, unless I'm much mistaken, I could consider leaving out the A-130 in my initial build if the A101-2 has a linear response, or vice versa if the response in exponential.

Kind regards,

Nick,
Cardiff, UK.

Re: [Doepfer_a100] A101-2 in VCA mode

2013-11-03 by Florian Anwander

Hello Nick

The A-101-2 contains a exponentiator circuit, but an opto coupler does 
not have an exact response curve. That means: the A-101-2 will be 
"something similar as exponential".

But there is another reason why you should have a OTA based VCA: Opto 
couplers are slow. You never will get that fast response, that a OTA 
base VCA like the A-130/A-131 can provide.To be honest: I'd recommend a 
A-132-3, then you have a linear and an exponential VCA. Usually you need 
a linear VCA for the envelope modulation and a exponential VCA for LFO 
modulation. In the A-132-3 you have both.

Florian

RE: Re: [Doepfer_a100] A101-2 in VCA mode

2013-11-04 by nicholas.buckley@ntlworld.com

Hi Florian,

Thank you very much for your extremely clear explanation - I'll certainly be including one or more dedicated VCAs now!

Indeed, I had totally overlooked the A132-3 which seems an excellent alternative to adding a separate A130 and A131.

Best wishes,

Nick

---In Doepfer_a100@yahoogroups.com, <doepfer_a100@yahoogroups.com> wrote:

Hello Nick

The A-101-2 contains a exponentiator circuit, but an opto coupler does
not have an exact response curve. That means: the A-101-2 will be
"something similar as exponential".

But there is another reason why you should have a OTA based VCA: Opto
couplers are slow. You never will get that fast response, that a OTA
base VCA like the A-130/A-131 can provide.To be honest: I'd recommend a
A-132-3, then you have a linear and an exponential VCA. Usually you need
a linear VCA for the envelope modulation and a exponential VCA for LFO
modulation. In the A-132-3 you have both.

Florian

Re: [Doepfer_a100] A101-2 in VCA mode

2013-11-04 by Zoë Blade

> Indeed, I had totally overlooked the A132-3 which seems an excellent alternative to adding a separate A130 and A131.

I swear by the A-132-3, for what it's worth.  It lets you add velocity sensitivity if you use its two parts in serial.  And if you don't need velocity sensitivity, it can temper anything unrelated, such as the intensity of some frequency modulation, for instance.  I find it *much* more useful than having a single VCA of only one type, with CV inputs that are added together instead of multiplied.  Really, I'd consider the A-132-3 the default or standard VCA unless you have a special requirement.

All the best,
Zoë.

Re: [Doepfer_a100] A101-2 in VCA mode

2013-11-04 by Scott Rogers

All this talk about the A-132-3 got me thinking about it, but when I looked at the web site price list I found there is no link to the product page. Is it still available?

Scott

At 03:08 PM 11/4/2013, you wrote:

Show quoted textHide quoted text

> Indeed, I had totally overlooked the A132-3 which seems an excellent alternative to adding a separate A130 and A131.

I swear by the A-132-3, for what it's worth. It lets you add velocity sensitivity if you use its two parts in serial. And if you don't need velocity sensitivity, it can temper anything unrelated, such as the intensity of some frequency modulation, for instance. I find it *much* more useful than having a single VCA of only one type, with CV inputs that are added together instead of multiplied. Really, I'd consider the A-132-3 the default or standard VCA unless you have a special requirement.

All the best,
Zoë.

Re: [Doepfer_a100] A101-2 in VCA mode

2013-11-04 by Zoë Blade

> All this talk about the A-132-3 got me thinking about it, but when I looked at the web site price list I found there is no link to the product page. Is it still available?

It looks like it *was* only available while stocks last, then Doepfer redesigned it to no longer use a rare chip, so it's now effectively unlimited again, yay!  So it should still be available, yes.

http://www.doepfer.de/a1323.htm

Hope that helps,
Zoë.