Vacuum Tube Optical Compressor Module
The RMSMC5 Valvop from Roll Music Systems.
A real, transformer-coupled tube optical compressor in the convenient package you never thought possible.
At long last, all the warm sweet satisfaction of an optical compressor with a real transformer-coupled, high-voltage vacuum tube audio path in the convenient and cost-effective 500-series modular format.
You love the sound of the RMS5A7 Tubule tube mike preamp module, and now you can enjoy that same sonic bliss in a line-level compressor and the same form factor. The compression is all optical for a smooth compression that's ideal for both vocals and electric bass. (But don't let us stop you there!) The audio path uses the same all-tube amplifier circuit found in the Tubule.
There are only 10 gray panel versions that were made and they have a slightly different circuit than the blue panel versions.
Discussion thread: https://gearspace.com/board/product-alerts-older-than-2-months/877995-new-500-series-vacuum-tube-optical-compressor-roll-music-systems.html
The earliest units (those ten gray-face and the first ten or so blue-face) used an input transformer with a different turns ratio. The new ones have a lower transformer turns ratio, which means the internal gain structure of the amplifier is different, producing more of our tube amp's signature flavor. From the user's perspective, the makeup gain range still goes from -2 to +20dB. It now has the amplifier coloration at the +6dB setting that it used to have at the +20dB setting. The compression hasn't changed.