*Please note -- this item is pre-owned and may show signs of use. Includes a six-month Alto Music warranty! Owned by John Rzeznik of the Goo Goo Dolls

The Vacuvox U23 vari-mu compressor limiter builds upon the legacy of the Vacuvox CL-2 for which the Rohde & Schwarz U-23 broadcast limiter served as a basis. Several improvements have taken the design and functionality of the CL-2 a step further while preserving the euphonic sound of the original.

The Vacuvox U23 has an all class-A vacuum tube audio path, and side-chain path based upon the original circuit of the Rohde & Schwarz U23. These ensure unparalleled performance and provide unrivaled headroom and transparency.

The Vacuvox U23 compressor limiter has been assembled entirely by hand and uses high-quality modern components. The custom-made transformers are faithful recreations of the original, sonically excellent, Rohde & Schwarz transformers. The four audio transformers are made of permalloy with 80% nickel and 20% iron content. The chokes and power supply are made of SiFi. The power transformer is upgraded for better noise performance and stability.

A different layout of the front, a modification of the output gain and the thresholds and 2 extra gain stages are the most significant improvements that have been incorporated in the Vacuvox U23 and U23m.

The Vacuvox U23 is aimed at general tracking and mixing and uses precision potentiometers for input, output, attack, and release.

21-stepped switches for input, output, attack, release, and threshold are used for our mastering version of the U23; the U23m. These extend the use of a pair of U23m compressor limiters to critical stereo applications for many different genres of music. Even jazz and classical material can be mildly compressed with a perfect stereo balance and without sacrificing the sense of dynamics and producing unwanted artifacts.

The various gain structure options from the Pad, Input, Gain and Threshold offer the possibility to create different kind and levels of saturation subtly. Therefore the sound can be varied between transparent, dense and fluid by lowering the threshold, driving the input transformer or driving the tubes.