Utter Decay - 2hp Quadra Expander (+ decay knob fix)

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Bogus
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Utter Decay - 2hp Quadra Expander (+ decay knob fix)

Post by Bogus » Wed Feb 04, 2015 12:36 am

*please excuse my misuse of the phrase "cross-modulation" at 2:28... Oops!! :bacon:
[video][/video]


UPDATE: fixed the Decay Knob being cut, just used a couple 1N4148 diodes per channel.

[video][/video]


This is a 2hp mini expander for Intellijel's Quadra. It taps into the Decay CV and EOC output via the jumpers on the rear of the Quadra. This allows for intricate cross modulation of the four envelopes in a compact package.

Image

This cost me about $10 to make, same as a DIY Mult just with a couple ribbon cables added for routing. Below are pictures and some details so you guys can construct your own!

Here's how the cables connect:
Image

Here's a little diagram explaining routing:
Image
Image

'A' is the part that the mono cable tip grabs when inserted, this carries the signal to or from the module. 'B' is a normalization terminal, in this circuit it carries the offset of the decay knob until a patch cable breaks that normalization allowing for modulation to occur.

*NOTE: Decay CV is handled by the top right terminal while EOC is handled by the middle terminal labeled expander 4
Last edited by Bogus on Wed Feb 04, 2015 9:55 pm, edited 6 times in total.
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jenz
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Post by jenz » Wed Feb 04, 2015 1:02 am

Nice!!! Matbe this will be my first DIY project when you'll post the recipe :tu:
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CF3
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Post by CF3 » Wed Feb 04, 2015 1:34 am

:yay:
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Post by FrankMurder » Wed Feb 04, 2015 5:06 am

Following this
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Donderdag
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Post by Donderdag » Wed Feb 04, 2015 5:35 am

Cool! :tu: I've been eyeing the Quadra for some time but was turned off by needing twice the space to access the CVs. This might change my mind...
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Neo
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Post by Neo » Wed Feb 04, 2015 5:39 am

Awesome! Ok, *now* I want a Quadra.
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AAG
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Post by AAG » Wed Feb 04, 2015 10:35 am

Wow. If I could have a 2-4HP module to access both A and Decay parameters I would definitely get that instead of the expander!!!

There might be a market for this :)
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nullpunkt
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Re: Utter Decay - 2hp Quadra mini Expander

Post by nullpunkt » Wed Feb 04, 2015 11:40 am

Bogus wrote:I'll get some shots of the Quadra PCB up here soon so you guys can build these for yourselves.
Oh yes please. This will raise your karma up to a new level...
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nullpunkt
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Re: Utter Decay - 2hp Quadra mini Expander

Post by nullpunkt » Wed Feb 04, 2015 11:40 am

Double Post...
Last edited by nullpunkt on Wed Oct 14, 2015 7:02 am, edited 1 time in total.
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Post by chvad » Wed Feb 04, 2015 1:14 pm

:bananaguitar:
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albiedamned
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Post by albiedamned » Wed Feb 04, 2015 3:16 pm

Isn't this pretty much how Intellijel itself started - by making a small expander module (Mind Meld) to a popular large module (Vulcan Modulator) that everyone liked?
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Citisyn
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Post by Citisyn » Wed Feb 04, 2015 3:50 pm

Awesome! I was just thinking of getting a quadra and doing something similar since I don't have room for it and the expander. Glad to know it can be done.
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Post by waves_of_awesome » Wed Feb 04, 2015 4:21 pm

:sb: Might have to build this, great idea!
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Bogus
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Post by Bogus » Wed Feb 04, 2015 4:27 pm

Details on how to wire up the jacks are now in the OP!
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Post by maudibe » Wed Feb 04, 2015 5:51 pm

Nice :)
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Post by pwranml » Wed Feb 04, 2015 5:51 pm

Might consider swapping out my expander for one of these especially since I have a mult I never use.

Could the problem with the decay knob no longer functioning be solved by patching your modulation source into a mixer as well as an offset voltage? then the mixer knob of the offset would work like the decay knob? This might make no sense I'm just guessing.
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Citisyn
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Post by Citisyn » Wed Feb 04, 2015 6:18 pm

pwranml wrote:Could the problem with the decay knob no longer functioning be solved by patching your modulation source into a mixer as well as an offset voltage? then the mixer knob of the offset would work like the decay knob? This might make no sense I'm just guessing.
Yeah, that should do it. If you're electronics savvy you could build the mixer behind the panel (probably need another 2hp) and use the "B" signal as the offset, making the decay knob functional.
EDIT: Now that I think about it, you could hide the mixer circuit behind the quadra and keep the expander as 2hp. Ok, now I need to buy a quadra :hyper:
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Bogus
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Post by Bogus » Wed Feb 04, 2015 6:26 pm

pwranml wrote:Could the problem with the decay knob no longer functioning be solved by patching your modulation source into a mixer as well as an offset voltage? then the mixer knob of the offset would work like the decay knob? This might make no sense I'm just guessing.
That's what I do in the demo video when I patch the bottom Decay CV. It's an LFO with about 2 volts of offset from a Doepfer A-176.
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Post by pwranml » Wed Feb 04, 2015 8:43 pm

Bogus wrote:
pwranml wrote:Could the problem with the decay knob no longer functioning be solved by patching your modulation source into a mixer as well as an offset voltage? then the mixer knob of the offset would work like the decay knob? This might make no sense I'm just guessing.
That's what I do in the demo video when I patch the bottom Decay CV. It's an LFO with about 2 volts of offset from a Doepfer A-176.
Awesome. Just to be clear the knob does still work as long as you don't have anything plugged into the decay cv right?

If you have any more pictures especially of what it looks like all wired up that'd be appreciated. It seems super simple but pretty I'm new at this. Also what are those little white jawns that you're using to connect the cables to the pins?
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Bogus
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Post by Bogus » Wed Feb 04, 2015 9:05 pm

I fixed the knob being removed from the circuit, there's a video posted in the OP. I'll get new instructions posted here soon but for now I'm going to mess around with this.
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Post by stressstest » Wed Feb 04, 2015 10:04 pm

Thanks so much :yay:
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Post by KNYST » Thu Feb 05, 2015 6:31 am

This is a great idea. Thanks for sharing.
If I build one, I would definitely add jacks for attack CV as well :party:
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pwranml
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Post by pwranml » Tue Mar 03, 2015 10:56 am

Anyone else build this yet?

About to order the diodes. Little confused on the whole hookup still.

Also wondering if it'd be possible to wire up a "both" cv jack?
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Post by sjessiman » Tue Mar 03, 2015 12:21 pm

Love this, Quadra is great but I'm having a hard time fitting the full exander into my plans. :yay:
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Citisyn
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Post by Citisyn » Tue Mar 03, 2015 12:25 pm

pwranml wrote:Anyone else build this yet?

About to order the diodes. Little confused on the whole hookup still.

Also wondering if it'd be possible to wire up a "both" cv jack?
I built mine with attack and decay, so a "both" should be possible.
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