Frap Tools CGM Creative Mixer Eurorack Quad Stereo Channel Module (QSC)

The Quad Stereo Channel (QSC) consists of four stereo channels, with a design based on the Channel module that, however, also borrows some concepts from the Group and the Master modules. The color scheme reflects the same routing of the modules: VCA (red), two effect sends (yellow and green), pan (pink), auxiliary input (purple), and main faders (white).

This peculiar feature set allows you to use the QSC within a standard CGM configuration, or as a standalone stereo mixer with mono effect sends.

Four Voltage-Controlled Stereo VCAs with Saturation

Each channel features two amplitude controls: an input stereo VCA and a volume fader. The input VCA is voltage-controllable and, if the signal has enough amplitude, it can overdrive the circuit with a creamy, fat saturation. A peak LED tells when the signal is clipping, but don’t fear cranking it up!

Local Sum Output

Two unbalanced outputs (left and right) provide the local sum of the four channels. They allow you to use the QSC as a standalone, four-channel stereo mixer in smaller systems or parallel-process a QSC in larger setups.

Two Effect Sends per Channel (with CV)

The yellow and green knobs are two effect sends levels. They can work pre- or post-fader, and two of them can be voltage-controlled for expressive and creative results.

Pan/Crossfade Selection (CV?)

A switch lets you use the panpot for stereo placement or for crossfading between two monophonic sources. This last behavior can lead to using the QSC as a limited but effective eight-channel mono mixer! The first and fourth channels’ pan/crossfade sections can also be voltage-controlled.

Mute Buttons

The mute buttons allow you to remove a channel from the group sum with a click. The mute function works over the input VCA, so it will also mute the effect sends.

Solo-in-Place Switches

The Solo-In-Place button lets you prepare a “scene” of channels to be isolated from the other ones, and then recall it through the Safe Solo button on the Group module. It can be seen as a mute group function that allows you to mute all the channels outside the solo scene with a click.

PFL Switch

Push the PFL button and rotate the PFL fader on the master module to preview a channel: it’s convenient for tuning your oscillators or checking if everything is ok before bringing whatever sound source into the mix.

Mono Effect Send Outputs

Two monophonic jack outputs mirror the effect send sum sent to the group. In this way, you can take advantage of the QSC effect sends capabilities even in a compact system, where the group cannot fit. In larger setups, you can achieve some advanced effect routing by processing the same sum in two ways: one from the group and one from the QSC.

Auxiliary Mono Input

Should you run out of channels, the auxiliary mono input lets you add an additional monophonic signal to the final sum: no attenuation, no controls, just a straightforward input circuit!