Quadrax VCA

Eurorack
#1

Can the Quadrax be used as a VCA? Does this require alternate firmware? I’d really love to get a Quadra, because I’m designing a desert island setup for a palette 62 case, so every HP is valuable. My original design had the quadra, at 12 hp, as one of the last modules in my setup. Unfortunately, I can’t find one anywhere! Neither Sweetwater or the Intellijel site even list it, even on the discontinued modules section. The Quadrax is two hp wider, and wouldn’t fit in my setup without a serious remodeling of the entire setup. However, I noticed that it had CV inputs and was wondering if those could be treated as audio inputs, while using the triggers for envelopes that would control an internal VCA. Is this possible?

Edit: I just read the manual. What I’m looking for can be achieved exactly with burst mode. RTFM

this is my current ideal setup. If I cannot buy a quadra, should I go for the dual ADSR or the quadrax? If I go for the quadrax, would I be able to do away with the 1u VCA’s? What should I put in there instead?

I’d appreciate any help you can offer, and I’m sorry if I’m rambling here.

#2

I think it’s worth making room for Quadrax. You can’t use it as a VCA, but you could set a channel to LFO mode, turn it up to audio rate, then use an AD Envelope channel to control LEVEL of the LFO channel to make it function basically as a VCA for the internal signal. This just wouldn’t work for external signals.

A few other notes:

  1. You won’t be able to use both the Stereo In and Stereo Out 1U because only one of them can connect to the Palette case jacks at a time.
  2. How did you plan to use XY? The only things in there with 3-pin jumpers are the case jacks and the Stereo Line Out 1U output.
  3. Shifty is an interesting choice, but I feel like it’s better suited for a larger system with more voices. Triplatt might be useful because I don’t see any attenuverters.
  4. The dual Unity Mixers and Dual VCA 1U seems a little redundant to me.
  5. It’s very possible that you have a specific plan for your system that I don’t understand, so feel free to ignore all of the above!
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#3

1-2. I was planning to use the xy io in tandem with the stereo ins/outs to accommodate the 3.5mm stereo jacks. I believe it’s possible, but not with the supplied jumper cables.

  1. I don’t remember why I put the shifty in there. You’re right, a triplatt would be a much better fit. That will probably work its way into the final design.

  2. One set of dual unity mixers would be for mixing the oscillators, and the other would be for mixing cv if I wanted to offset the sequencer with either midi or a tetrapad channel.

  3. This would be my first hardware synth, so it’s quite true I’d have no idea what I was doing, but a two-voice-paraphonic synth sounded fun.

All that said, what would you suggest I lose in favor of making space for the quadrax? One of the mixers?

#4

Oh ok, connecting XY to Stereo Line In 1U would require a custom cable to go from the 3-pin molex header to the 6-pin header. I haven’t heard of anyone trying this so I’m not sure how it would turn out.

Yes, I think you could lose one of the Unity Mixers. With the Dual VCAs and Triplatt you should be able to fill your wave mixing duties.

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#5

There is a quadra available at long and mcquade at there eastern avenue store in Toronto. It is not listed on there website.

#6

Probably best to use Quadrax as modulation and envelope source and just get something to act as a dedicated VCA.

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