Micmix Master Room XL-305 stereo spring reverb

MicMix XL-305 rackmount spring reverb. Very nice sounding spring reverb, uses a spring chamber with 12 springs that are tuned in a specific way to give a smooth and natural sounding reverb, not sproingy like other spring reverbs. Can be operated in stereo with two inputs, or you can process a mono signal in stereo using the mono chamber drive button, so that you can feed both channels with either the left input, right input, or the sum of both. The right and left channels have different timing characteristics, so you can give a mono signal a true stereo spread. Also has a mono chamber return switch, which feeds the input signals through both sides of the reverb processing, effectively doubling the echo density. Has a four band peak/dip eq on each channel, so that you can tailor the reverb sound.

This is an all analog unit, so you can also get some interesting sounds by overdriving it slightly.

In good shape, case has some wear, including some corrosion on one top edge (see pics) which already was there when I bought it decades ago. Functionally very good, the only issue is the 6khz eq knob on the right channel is a little noisy when being adjusted.

From MicMix:

The MicMix XL-305 Master Room reverb is a unique design approach in self-contained reverberation systems. This acoustic chamber synthesizer incorporates a new technology that stems from years of research and analysis of "live" chambers currently in use in the recording industry. Properties such as room volume, echo density and reverberation time versus frequency were studied. The most desirable characteristics of these live chambers are incorporated into the XL-305. The result: the sound of a live acoustic chamber in a rack-mount package. A live chamber doesn't have the boing, twang, and flutter that are normally found in compact reverberation units. The XL-305 produces none of these unwanted sounds. A percussive attack, or any transient signal, is difficult for most compact reverbs to reproduce naturally. Under these conditions, a reverb is most likely to produce undesirable side effects. The performance of the XL-305 under transient conditions is outstanding. XL-305 offers two channel stereo capability and is easily switched to stereo imaging of a monaural signal or full mono operation. Each channel features an INPUT LEVEL control, LED CHAMBER DRIVE indicators and an OUTPUT MIX control to blend the direct and reverberated signals. Front panel OUTPUT LEVEL adjustments are provided for easy adaptation to various operating levels of other equipment. AUX INPUTS & OUTPUTS located on the front panel automatically defeat the rear panel connections, allowing convenient patching. A four-band EQ allows each channel of XL-305 to simulate the sound of reverberation plates, live chambers and concert halls. This peak/dip EQ has a control range of plus or minus 12dB with center frequencies at 150, 600, 2k and 6k Hz, thus providing the user with extreme flexibility and creative freedom. Low acoustic susceptibility permits the unit to be located in the same room with loudspeakers operating at high levels without acoustic feedback or mechanical interference. This, combined with the XL-305`s rugged construction, lends itself to the rigors of road use without special handling. All of these features are packaged in a 3 1/2 inch rack-mount unit that is easily installed and incorporated into any system. Ruggedness, dependability and ease of operation are a part of every Master Room. The XL-305 is the most significant advancement in quality for self-contained reverb systems. The Acoustic Chamber Synthesizer is the result of a commitment by Master Room to provide the finest in reverberation for a wide range of professional audio applications. This unit is a must for those who demand superior performance in their studio, broadcast, or sound reinforcement systems.