Do I really need a VCA?

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robkramble
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Do I really need a VCA?

Post by robkramble »

May be a dumb question considering how everyone is a unique flower in the modular world with different needs, etc.

Do I really have a use for a VCA? My modules atm consist of two filters, an envelope generator and an LFO. I use these to do some stereo filtering for my ITB sounds. I feel like I could use fades or the envelopes on my sampler to achieve what a VCA would do at much less cost (free!).

Am I overlooking some fun uses of a VCA in my current setup?
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Filch
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Post by Filch »

The general motto around here is :
"You can never have enough VCA's"

So with that, I send you off on a wonderful journey with the search function.
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Post by richard »

yes

send the output of your envelope generator or LFO to it

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fredguy
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Post by fredguy »

You don't need a vca.

VCA's just enhance modulation exploration. :party:

I started out not using vca's much and then came to understand what they brought to the party.

After playing guitar and bass for 20 years I dig modular synth's because it's easier for me to make new music and explore things on the modular since I make all the rules. I bring what I think fits into a band setting, with some friends I've jammed with for years, and the rest I enjoy myself or share with wigglers who, like me, have a more open mind on what constitutes music.
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rezzn8r
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Post by rezzn8r »

you're not getting the most out of your EG without a VCA, but with only 2 filters, and EG, and a LFO you might buy a couple other modules 1st.
a fun patch for a vca in your setup would be dynamic FM on your filters.
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hiawog
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Post by hiawog »

surly dis be jocular. use yous vcas all de time.

more seriously. yes. everyone needs vcas to make interesting things possible.
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phasebash
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Post by phasebash »

Basically, yeah. If you want to be able to dynamically control the amount of modulation for any given signal routing, you'll need a VCA to do this.

Bear in mind which modules of yours have built in attenuators for given settings and offsets. Ie: Pulse width (the offset) and Pulse width modulation (the attenuated input). I note this b/c you can get by with a lesser VCA in this instance.

Some VCAs have built-in offsets (Doepfer calls this Gain, Pittsburgh calls it Index), which are very useful for signal inputs which don't have an associated offset for the given parameter.

Tip: don't overlook Doepfer VCAs or the 4ms VCA matrix!
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robkramble
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Post by robkramble »

I totally derped and overlooked the use of a VCA as a CV router... new to the modular game. :hihi:

I'm thinking of getting the Intellijel VCA cause it's dual, only 6hp and has a continuous slope adjustment. Seems like a steal @ $155 tbh.

Thanks for the reminder guys.
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dj2sday
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Post by dj2sday »

fredguy wrote:You don't need a vca.

VCA's just enhance modulation exploration. :party:

I started out not using vca's much and then came to understand what they brought to the party.
I am new to modular. can you expand on this?? i know they are amps but how would they be used to help modulations.. sorry if this is a rally stupid thing to say.
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Post by chvad »

they give you the ability to dynamically open and close CV or audio using other cv sources as control mechanism. Envelopes can shape the sound by opening and closing a VCA. LFO can modulate the sound (trem). They can open and close CV routed to others sources. Basically it allows you to have a level of intention with audio and CV. Otherwise you're basically always ON. I have 7 vca's in my system.
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Post by Matos »

Not rally stupid at all. Vcas can kinda be thought of as the size of the hole your cv or audio goes through. Feed it a gate, when the gates high the signal goes through. When gate of off, signal gets stopped. Feed it an envelope that shapes the size of the door, so as the slope rises more of the signal gets through, and vice versa. Now, you can take that envelope and have it control filter cutoff , so if you had an lfo patched into the vca, you could control the amount of lfo affecting the cutoff. In a sense, a vca gives you voltage control over any output. If you have and external delay with no cv, feed the delay at full and use a vca mixed with the original signal to control when the delay is mixed. You can have long drones where the vca controls the wet dry of a bit crusher, etc. the possibilities are endless.
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obscurerobot
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Post by obscurerobot »

No, you don't need a VCA.




You need many VCAs!

You are probably getting away with using you LFO and envelopes with the attenuators on the inputs to other modules. But with VCAs, you can modulate the modulators, in ways the module makers never intended.

This is the Tao of the modular.
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Post by boramx »

i personally think you should have about 2 VCAs per 3u of modules.

i have 12u, thus i have 8 VCAs (style and flavor varies amongst them).

maybe you're not there yet, but you will need and want them eventually.

monosynth type signal flow typically only needs one VCA, but multitimbral patches, percussive stuff, dynamic timbre shaping, panning, all of these things need VCAs, lots of 'em.
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Post by Drumdrumdrumdrum »

:vcas:
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fiero
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Post by fiero »

i'm looking for a very vintage loud sounding vca like the ms 20 or arp Odyssey any suggestions?
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haima
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Post by haima »

fiero wrote:i'm looking for a very vintage loud sounding vca like the ms 20 or arp Odyssey any suggestions?
Oakley Classic VCA is a discrete clone of the ARP 2600 vca... and it sounds great (I keep saying this, haha).

Most of the other VCAs on the eurorack market use VCA or OTA chips which generally speaking are cleaner sounding, but distort more suddenly if you push them to their limits. A lot of people DO like the sound of these IC based VCAs clipping - the Intellijel uVCA and malekko VCA do have a cool type of distortion, but possibly not what you are looking for.

The MS-20 vca is super simple (one transistor and an opamp from memory) - you could fit it on a piece of strip-board the size of a postage stamp. If you are at all DIY inclined I would buy a doepfer blank panel and make one yourself. This option will probably give you the raw sound you want.

The ARP odyssey VCA I've seen uses a CA3080 OTA chip - some of the cheaper doepfer VCAs use these, so that could be a way to get that sound. The MS-20 / JX-3p single transistor style will have more grit though.

Also, Manhattan Modular (negativspace) is making a MS style filter and vca combination module soon - here's the thread about it...

Also there is the Miss10 VCF/VCA PCBs - which are a related DIY project.
Last edited by haima on Tue Feb 28, 2012 5:47 pm, edited 1 time in total.
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Post by fredguy »

dj2sday wrote:
fredguy wrote:You don't need a vca.

VCA's just enhance modulation exploration. :party:

I started out not using vca's much and then came to understand what they brought to the party.
I am new to modular. can you expand on this?? i know they are amps but how would they be used to help modulations.. sorry if this is a rally stupid thing to say.
When I started with my modular I thought of vcas as something that you used to gate sound, ie before or after a filter, east coast style. Since my first filters, a z2040 and a boogie then I added a qmmg, all had built in vca features I skipped getting other vcas.

I had fun patching.

Then I realized it would be fun to modulate things. For example, I can use an lfo to modulate the pitch of an oscillator. I can set the amplitude of the lfo to output +/- 1V and get a +/- 1 octave pitch change. If I take that lfo and run it into the input of a vca and take a second lfo and plug it into the cv input of the vca I can now vary the +/- 1V pitch variation with the second lfo. Makes for more interesting pitch changes. Now I take a second vca and use it to modulate the wave shape of one or both of the lfos now things are getting fun. Once I got my head around this I realized I could do the same things to filters, fm operators etc. For me it took quite a bit of patching before I realized what I wanted to do then I realized

:vcas:

But starting out not so much.

But then again I'm an engineer and it takes me a while to grok things.
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phasebash
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Post by phasebash »

robkramble wrote:I totally derped and overlooked the use of a VCA as a CV router... new to the modular game. :hihi:

I'm thinking of getting the Intellijel VCA cause it's dual, only 6hp and has a continuous slope adjustment. Seems like a steal @ $155 tbh.

Thanks for the reminder guys.
That's the perfect place to start. I totally halliburtoned out and got a new vca4mx to start, bad idea.
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Post by VanEck »

I made due without any VCA's for a while, and used my filters as a substitute when needed to close the signal path or to modulate velocity. All depends on what you want to do though... traditional synth patches or percussive patches will be hard to do without a proper VCA or fast LPG.
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Post by Soundoferror »

Oops nevermind then
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Post by Soundoferror »

what i meant to say was, yes all good advice above on how to expand your modular vocabulary with vca, however my live rig is vca less and spits out plenty of delicious sounds so again it depends on what you want to achieve
Last edited by Soundoferror on Tue Feb 28, 2012 5:55 pm, edited 1 time in total.
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cycles
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Post by cycles »

I don't think this a silly question at all. I only have one VCA so far, my A-109 (and even then, it's part of other stuff) so I also haven't fully understood the need for one. Especially when things like the HexVCA are £240.00 -- that's an awful lot of money to someone like me (and maybe you) who thinks they are just there to make things "quieter" or "louder".

As this thread has shown, there purpose is a lot more than that. That said, I still don't quite understand how it's £240 worth of value :lol: But I'll get there in time, that's the beauty of modular - you learn as much as you want as fast as you want
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Post by Thonk Support »

I think in most patches 75% of my vcas are acting purely on control voltages rather than audio signals.

And in fact I'll often have patches without vcas acting on any audio, but never patches when vcas aren't acting on control voltages.

vcas are next level shit y'all.
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Post by richard »

I think the fact they are called Amplifiers is a bit confusing

VCA should really stand for Voltage Controlled Attenuator as hardly any of them amplify anything.

Or is there a technical reason this is not the case?

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Post by ringstone »

haima wrote:The MS-20 vca is super simple (one transistor and an opamp from memory)
This is true, it's much the same as the basic VCA in the MS-10. However the MS-20 has a second VCA, and that is quite a bit more interesting. It's a vactrol-controlled VCA, which means there's some slew in the response to the CV that opens it, and this is one area where VCA's become quite important - in the role of (often) subtly colouring, or changing the signal that is passed through them. In the case of a vactrol-controlled circuit, this results in a sound could be described as being "plucked" - with a quite "natural" sounding decay.

So VCA's are often said to have a linear, or exponential response, and some are in-between, and some can be continuously varied between the two types of response. All of which has an effect on how CVs fed into them will affect the signal passed through them, in ways that would be difficult or impossible to achieve otherwise.

So, in a sense, the response type or characteristics of a VCA could almost be thought of as a special sort of "filter" for CVs, changing them in subtle (or not-so subtle) ways...

Also, audio can be used as a control voltage for a VCA as well. The results can be similar, but not the same as, a ring-mod (which is somewhat related to a VCA!).

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