If you are new to synthesisers, or just modular synths, this section is well worth reading. It will also be helpful if you are trying to decide what AE modules to buy.
The easiest way to start is to purchase one of the 2 starter systems on the Tangible Waves website, or local distributors/shops in your country. Both these systems will get you started with minimal technical knowledge required.
There is a lot of discussion/ advice/ knowledge available on the AE modular forum, if you get stuck, don't be afraid to ask, we don't bite! We also also mercifully free of internet trolls. Click on the support button to the left.
If you are wanting to spec your own system, you need to decide what it is for, if you want it to be a self contained noise machine, then you need all the usual synth parts - Oscillators, VCAs, Filters etc. It is a cheap way to expand many commercial synths, most especially semi-modulars like the Arturia Minibrute, Behringer Neutron etc. The ones mention even share the 3.5mm mini jack size with the 4 I/O module so the leads are easy. It is highly recommended that all external inputs to the AE go through the 4 I/O module to protect the circuits from voltages outside the 0-5V range it uses.
The AE Modular can be completely self contained, but has a midi in on the Master module so you can sync (or play) from external equipment. This currently is the only way to have a keyboard for the AE; many users on the forum use the Arturia Keystep but any keyboard/synth with a midi out can be used.
If you are not getting a sound from the AE, check your output connection (or headphone volume). The easiest way to check then is to use a long patch lead and start with the oscillator direct to the output (the AE's multiple outs on every module are very helpful for this). If that makes a noise then move to the output of the module the oscillator is going to, if that makes a noise move to the output of the next module until it goes quiet and you've found your problem. It can be a loose patch wire, but could be extreme settings of knobs/CVs.