Model Mk1 is based on the very early variable-mu* designs from the 50s. Due to its extremely high control voltage it doesn't impart any audible "thumping", most other variable-mu* designs suffer from at high GR and fast timing constants. Also it has a very simple signal path, where the compression happens directly in the audio path. The result is a very natural compression character with very little distortion. The arrangement of four(!) variable-mu* stages add to the incredibly dense and thick nature of Mk1. Mk1 is the most colored of MJUC's models.

Model Mk2 is built upon the more complex designs of the 175 and 176 from the early 1960s, the all-tube-predecessors of the classic 1176 FET compressor. It offers four ratios, a density switch, that enables a second variable-mu* stage and reduces the program dependence of the attack and recovery timings to a minimum. Furthermore, it lets you activate the interstage transformer to reduce overall noise and distortion and making the compression more accentuated. Compared to Mk1 the second model is less Jazz and more Rock'n'Roll with enhanced generated harmonics and a more forward sounding character.

Model Mk3 is the least colored and most Hi-Fi-sounding model in MJUC. It is Klanghelm's modern interpretation of this compression topology. The only design idea derived from another modern famous variable-mu* comp is, that it's circuitry is done entirely differential, making the unit very quiet and almost distortion-free. But the real special thing about this model is, that the actual compression is done by two different variable-mu* stages, which kind of work against each other, one works feedforward, while the other in a feedback configuration. This results in a attack accentuating, punchy compression, surprisingly closer to a British G type bus comp than to a 670.

The first examples demonstrate how the different MJUC models perform on an acoustic drums phrase: first dry, then processed with each of the models. In each clip the only the respective model was used on the kick drum, snare drum, overheads, room channels as well as the drum bus. No other processing involved.

Then you hear the different models of MJUC on a full mix. To demonstrate the differences the examples are quite a bit more compressed than you'd usually do. MJUC shows about 6 dB GR in each example.

Next are some clips to demonstrate MJUC on electric bass. The differences between processed and unprocessed are fairly subtle, although each processed clip shows a gain reduction of around 10dB.

And finally MJUC on slow drums. Just like in the first examples only the respective model was used on the kick drum, snare drum, overheads, room channels as well as the drum bus. No other processing involved.