Pro Audio Sum & Distribution

333 / derived from triple three inputs to three outputs.


38 mm deep

48mA +12V   –   48mA -12V


The 333 is a summing and distribution module for eurorack modular systems.

It is composed of three identical sections, the red, yellow and green, each of those featuring a three inputs summing amplifier with three independently buffered outputs.

Derived directly from the CGM creative mixer series, the sum section is DC coupled, allowing the sum of control voltages as well as audio signals.

With an extremely low tolerance in both sum and output sections, it is suitable also for summing quantized voltages like the ones coming out from the quantized outputs of the SAPEL.

In case CVs or audio signals are particularly hot, the 6dB attenuator might be helpful to reduce exactly by 50% the incoming signals.

Red and yellow output are also normalled to the 1st jack socket of the yellow and green input: in this way this module can also work as a 1 to 9 buffered multiple.

Flexible I/O Patterns (1-9 to 7-1)

The 333 architecture allows you to use it as a mixer, as a buffered multiple, or both.

You can use the three sections together for sending one signal to up to nine outputs, or you can use the three inputs of a section to mix as many sounds or CVS.

Each section’s output is semi-normalled to the following one’s input so that you can blend up to seven signals.

A Perfect Mix

The 333 borrows some design choices from the CGM so that you can mix audio signals with an excellent summing stage and duplicate them.

The inputs are DC-coupled and allow you to precisely sum CVs as well.

Buffered Outputs

All nine outputs are buffered to guarantee a high multiplication fidelity.

Your V/oct signals will be safer than ever!

Switch Attenuators

If your audio signals are too hot, each section has a -6dB switch to halve the amplitude. If you patch CVs, they will be divided by two.

Since the three sections are connected, you can cascade the three switches and get -12 and -18 dB in the second and third sections, respectively.


The red led show positive signals while the yellow show negative signal. If you fed a section with a bipolar pulse signal, they would change their color from red to yellow according to the current signal polarity. If you feed a section with an audio rate signal, they will seem to be completely lit up, but they are actually oscillating between red and yellow as many times per second as the signal’s frequency.

You can achieve some results similar to the OR behavior when using trigs, but there might be some differences. If you patch, for example, two gate-on signals (say 5v each), a Boolean OR will output one gate (say 5V). If you patch the same two gates to the 333, it will output 10V (5V+5V).

We don’t sell directly. Please check our Reseller List to choose your favorite shop!

In Europe, we sell exclusively through our distributor: we do not have access to the individual shops’ orders or stocks.

In the rest of the world, we sell directly to the shops, but even in that case, there’s no way for us to know whether the modules that we’re restocking are sold, available, or reserved for another customer.

We restock every module at least once over a year: we focus on a module’s batch at a time, then we move on to the next one, and so on.

If you want an estimated delivery time for a specific module, drop us a line! We’ll be happy to answer you.