A-143-2 Quad ADSR - Power to the Quads!

Good value-for-money and serious rackspace-savers are Doepfer's Quad modules.
These modules offer four (-duh-) identical but individual modulation sources in one module.

My A-143-2 Quad ADSR is at the heart of my A-100 system.
With 4 envelope generators in one this is a very powerful module, and this is where the 3 individual gate outputs from my MAQ 16/3 come together.
Also see THIS post.

The Gate inputs of the units 2, 3 and 4 are normalled to the Gate input of unit 1, so Gate input 1 is connected to the switching contacts of the Gate input sockets fom submodule 2, 3 and 4 if no other input is connected.
With only one Gate signal applied to Gate input 1, it can be used to trigger all four sub-modules simultaneously.
A switch for each individual channel is available for switching between high, low and medium ranges.

All 4 sub-units have additional input sockets for Re-Trigger, but the re-trigger behaviour of the A-143-2 is slightly different compared to other envelope generators;
During the attack phase the envelope cannot be re-triggered or reset. (unlike the A-140 ADSR envelope, that envelope can be re-triggered while the gate is still open).

Each sub-unit also has three digital outputs (high/low) that sends a trigger signal at the End of Attack (EOA), End of Decay (EOD) and End of Release (EOR).

This is very useful if you want to daisy-chain the sub-modules to create more complex envelopes. (or even complete loops)
The envelope outputs are displayed with LEDs and the maximal envelope voltage (Attack/Decay reversal point) is about +8V.

The Quad series consists of the following Multiple modulation sources so far;
A-143-1 Quad AD, A-143-2 Quad ADSR 
A-143-3 Quad LFO, A-143-4
Quad VCLFO/VCO (just released), A-143-9
VC Quadrature LFO and modules A-142-4 Quad Decay, plus Quad Amplifiers A-132-2 Quad VCA I and A-132-4Quad exp. VCA