Description: Mattson Mini-Modular Voltage Controlled Mixer
Here is a MOTM-ized Mattson VC Mixer! From the Mattson website:
The VC Mixer consists of 4 channels.
Each channel has an associated gain control and control voltage input.
There are two outputs; Normal and inverted.
The control inputs respond to a 0-5V control voltage input. 0V is fully attenuated and 5V will produce a 100% output level.
The Level control attenuates the channel level.
The control inputs are cascaded. 5V is applied internally to the Control input for the channels and cascaded from channel 1 to channel 4. This allows the module to be used as a 4-channel mixer with no control voltage input to the Control in jacks.
When a Control input is plugged into a channel Control in jack, it interrupts the 5V from that channel through channel 4 allowing the gain for that channel, and all subsequent channels to be controlled by the new control voltage. New control voltages applied to the subsequent channels will interrupt the preceding channel control voltage for that channel and be applied to the remaining channels.
The trim pots on the circuit board are labeled with the associated CV gain adjustment and are set for a 1:1 input to output ratio. They can be trimmed to provide additional gain to utilize the mixer as an amplifier, if so desired. The gain will clip the original signal and can be set to overdrive the signal into a square wave peaking at the positive and negative power supply levels.
The mixer will work with both audio and CV inputs.
I used a Front Panel Express Panel of my own design, based on the MOTM jack grid like other recent panels I’ve been making. This grid allows fitting more pots into a smaller area.
The Mattson PC board is just a tad too wide to fit on a Bridechamber 3-jack bracket. I made an adapter bracket out of thin aluminum stock I got at Lowes. The adapter bracket mounts onto the Bridechamber bracket and then the board to the adapter bracket. This photo of the bracket shows the bottom side that attaches to the Bridehamber bracket. I matched the holes up to existing holes in the BC bracket, drilling out to 1/8-inch to work with some old PC motherboard standoffs I had.
Wiring up a Mattson DIY board is easy if you purchase the corresponding wiring kit. All I had to do was to trim the wires and connect them to the panel parts.