Parasound 106CX
A single-channel spring reverb that broadcasters and studios kept buying, and that Parasound later priced its successor against.
Overview
The 106CX is a mono spring reverb from Orban/Parasound, the joint venture that put the Parasound name on the map in professional audio before the company became known for consumer power amplifiers. It is a line-level, rack-oriented outboard unit built around a spring tank. It turns up in surviving studio gear lists of the mid-1970s as a piece that simply did its job. One Mix (August 1980, p.?) studio directory lists an Orban/Parasound 106CX next to a digital delay in a Savannah eight-track room.
The 106CX became the yardstick for its own replacement. When Orban/Parasound brought out the dual-channel Model 111B Spring Reverb, the company announced that the new two-channel unit would sell for the same money as the old single-channel 106CX - $695.00 including the power supply, per the announcement reproduced in the trade press. So the 106CX was the reference point, and the 111B was the value pitch. Recording-Engineer (April 1976, p.67) carried the same announcement. It noted that the 111B kept the 106CX's line-level balanced outputs and its smooth four-spring-per-channel sound, and added new tone controls and a floating threshold limiter to tame spring twang and protect against overload.
The 106CX is the simpler, mono, single-channel ancestor of a dual-channel design that kept its output stage and its spring character. The 111B's four-spring-per-channel tank and balanced line outputs were explicitly described as carried over from the previous model. Balanced outputs and a multi-spring tank are not what you find on a toy reverb, so the 106CX was already a serious piece of studio gear.
Physical details are sparse in the surviving documentation. The 111B is described as a standard 19-inch rack mount standing 3½ inches high. The 106CX shared its basic electrical design and output topology, so collectors reasonably expect the mono unit to be a rack-mount box as well. The exact panel dimensions of the 106CX itself are not confirmed in the available material. [VERIFY: 106CX chassis dimensions not documented; 111B is 19" rack, 3½" high.] Weight and depth figures circulate in service literature but cannot be tied to this specific model with confidence, so treat any quoted numbers with suspicion until a 106CX manual surfaces.
The control set on the 106CX is well established through its successor's documentation. The 111B added a bass control and a "quasi-parametric" midrange with ±12 dB of equalization, continuously variable center frequency, and adjustable bandwidth. The trade copy frames these as additions to a design that already had the essentials. The 106CX is the stripped-down version of the Orban/Parasound spring-reverb formula: a mono tank, balanced line outputs, and the four-spring sound the company carried forward unchanged. The 111B's "floating threshold limiter" was new, so the 106CX predates that refinement. That matters if spring twang on hot transients is a concern in your setup.
The 106CX gets you the sound of a 1970s studio spring reverb without paying dual-channel 111B money. It is mono, it is a spring tank, and it will do the dense, slightly metallic bloom that springs are loved and hated for. It is not a plate and it is not a digital reverb. What it offers is the sound of an American broadcast-and-studio spring unit from the mid-1970s, built by a company that was then more famous for pro reverb than for the home hi-fi amplifiers that would later define the brand.
The 106CX sits in an odd corner of the Parasound story. It predates the consumer amplifiers most people associate with the name, and it belongs to the Orban/Parasound era, when the catalog was aimed squarely at broadcasters and recording studios. That makes it a piece of the brand's pre-hi-fi history, of interest to Parasound completists and studio-reverb enthusiasts. It doesn't draw the attention or the prices of the company's later power amps. Condition and the presence of the original power supply are the practical concerns. The $695 figure from the period is a useful anchor for what these cost new, not a prediction of what one will fetch today.
Servicing is the usual story for spring reverbs. The tank itself is sturdy, but the electronics and the connectors are where age shows. Anyone buying one should confirm the balanced outputs are intact and that the spring tank has not been swapped for a mismatched replacement. Beyond that, the 106CX is a straightforward piece of mid-1970s pro audio, built to be repaired rather than replaced.
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