
Audified U73b Compressor
A faithful emulation of the German broadcast compressor/limiter unit U73b. The U73b Compressor is the 2nd generation of the famous plug-in, full of character and unique audio coloring.
“The German Broadcast Legend”
The original hardware U73b is an all-tube vari-mu compressor/limiter with an adjustable release time option that was often used for mastering between 1960 and 1980.
Audified was first to honor the analog device with its plug-in model, which popularity has been hard to match ever since.
After thorough analysis, Audified has kept the circuit exactly as it was originally designed and came up with a faithful mathematical emulation of the unit.
They added input and output gain (before and right after compressor circuit) to help with proper adjustment of the compression. The plug-in effect has been also supplemented with a VU meter and selectable side-chaining.
Working with the U73b Compressor is intuitive.
– Compressor/Limiter switch: The upper U73b knob switches between Compressor mode (Kompr), Bypass (Durchschalt) and Limiter mode (Begr). The compressor mode has lower threshold setting and very gentle increasing ratio. Conversely, the limiter mode provides a higher threshold setting with a higher ratio but still with the smooth knee.
– Release time: The first three positions offer fixed release time. The other three positions (marked red) provide adjustable program content dependent release time option.
– IN: Adjusts input gain before the compressor/limiter circuit
– OUT: Adjusts output gain after the compressor/limiter circuit.
– Key input: Selects the signal source used for controlling the gain reduction
– HPF: U73b is a vintage device and as such it may not meet present mastering demands. As a result, Audified added a bass management button that simply switches between original sound and desired modern sound (without low frequencies bypass).
I use Audified U73b Compressor on most of my mixes. Magic.
Two of the biggest strengths of the U73b is the way it handles bass (acoustic, electric, etc.) as well as vocals. There’s a lovely top end and clarity that this plugin provides — while at the same time adds roundness and warmth (due to the valve emulation).

- Quality and uniqueness of the sound of an unavailable original device.
- Award-winning plug-in.
- Precise valve circuit model.
- Faithful tube sound.
- External side-chain.
- Auto Output parameter.
- Oversampling.
