Toppobrillo Stereomix, Mint. Works great. 

4 channel voltage-controlled stereo mixer

Specifications

• 4 fully-featured input channels, with voltage control over LEVEL, PAN position and AUX SEND level.

• Pop-Free Muting | Cueing | Soloing. (long press on the LED Mute Switch enables SOLO for selected channel).

• -3dB compensated "constant power" pan law.

• Stereo Aux Return with level control. ("L/Mono" return normalized to "R" return for Mono if "R" is unpatched). Extra gain available for outboard effects.

• "Cue Mix" output available for use as pre-listen, a second FX send channel, alternate mix, etc...

• AUX send can be switched to PRE or POST fader for each of the four channels. -10dB pad available for aux send via jumper.

• Loud and super clean stereo headphone driver allows monitoring of either "Main Mix" or "Cue Mix" which allows for previewing input sources before adding them to the Main Mix. This can also be used to link to line level TRS outboard recording/processing devices, stereo send, etc... Independent level control of both headphone and main mix.

• Master volume control and dual 5-segment VU meterin​g.

• Efficient design. Relatively low power consumption and very low-noise/ low distortion audio path. Audio AC coupled through low-distortion "audio grade" film capacitors and a very low-noise opamp.