Studio Electronics ATCX
The ATCX is a 2U high rack-mounted monophonic synthesizer from Studio Electronics. It has two analog oscillators along with four analog filters and two LFOs. It features triangle, sawtooth, and variable square waves for the oscillators and these can all be active at the same time. Studio Electronics also added a new analog distortion effect, which is enabled via the Noise Level button. The ATCX also has three envelopes that are used to control the VCF, VCA, and modulating tasks. With this synth, it is also possible to switch between different hardware filters at the touch of a button. These filters share the same characteristics as those of the Moog Minimoog, ARP 2600, Roland TB303, and Oberheim Synthesizer Expander Module, which are all good choices.
The standout feature of this synth is the single rotary encoder in the center that is used for making all the edits. It is operated via several membrane switches on the front panel, which displays a value on the 3-character display above the encoder. This value can then be altered using the encoder, but bear in mind that some options are hidden away behind several pushes of a switch. Unfortunately, this means that the ATCX is not quite as smooth and fast to tweak as something with a bank of knobs. The limitations of the display also mean that you will need to consult the user guide to figure out what some of the abbreviations mean. For example, numbers are used to denote various waveforms. It's not exactly intuitive, but the ATCX came with a quick reference guide that explained everything.
Moving away from the front panel, the back panel features the AC input for power on the left with the MIDI Out and In next to it. Then there's a Ring Mod section with In and Out ring modulator connectors. Next is the Audio section with an Audio out to connect an audio cable and Ext In which is routed to the filter, LFOs, and VCA for timbre and modulation processing.
The overall style and design of the ATCX is a step back from the original ATC, which shared similarities with the Moog Source. Instead, with the ATCX Studio Electronics did away with the colored membrane switches and pastels colors for a look that is overall very blue. This synth was also on the expensive side for its time but can deliver a powerful sound that is appealing to many enthusiasts.