EMT MODEL-252
Sixty-two pounds of processor in four rack units, tethered to a control head you can park sixty feet away — EMT's third-generation digital reverb, and the one a reviewer called the most expensive on the market.
Overview
The 252 comes in two pieces. The mainframe is 4U of 19-inch rack space and weighs 62 lbs. It carries two fans that make a fair amount of noise, so EMT gave the engineer a control head on a cable. Standard practice runs the head up to 60 feet from the processor. With an external power supply that stretches to 300 feet.
The 252 is a deliberate departure from the large "spaceship-control" look of its predecessors. The rear panel is minimal: standard 3-pin XLR-type connectors for the single input and two outputs, plus a special 6-pin XLR-type connector for the remote. A period reviewer was surprised to find no RS-232 or IEEE interface back there. He called the limited control-expansion capability a severe oversight in an age of MIDI and expanding computer control. The front panel carries a power switch, fuse, and several LED indicators for input level, overload, temperature alarm, and memory error. A hinged plate secured by two thumb screws folds down for access to the important circuit boards.
Operationally the 252 follows the 251: mono-in, stereo-out. Conversion is 16-bit A-to-D with 20-bit internal processing. That lets the unit generate reverb without the high-frequency regeneration that lower-bit-rate systems lean on, and the faster processing yields smoother reverb tails. Seven programs ship in the box: Delay, Echo, Chorus, Non-Linear, Doppler Reverb, the old 250 Reverb, and Reverb. Sixty-four variations live in protected memory, with an equal number of locations open for user storage. Program selection is a button press. LED pointers then light up on a descriptive table showing which main parameters can be manipulated, and those are driven by buttons I through IV and a Parameter Lever toggled left or right. Anyone who has used a 251 will recognize most of the vocabulary.
The center section of the control head handles Time and Amplitude of reflections for the reverb programs, and delays for echo, delay, and chorus. Pan moves a reflection between the left and right outputs in 11 stages. That lets an engineer place a reflection image against a panned direct signal and suggest a room position. Left and Right refer to fixed-position reflections. Cluster controls the six-reflection cluster split across the two outputs that leads into the reverb tail. Four Time Scale LEDs and an LED readout display Time, Amplitude, and Panorama position, and a single +40ms button adds that offset to all parameters at once.
The Set buttons are where the 252 earns its keep in a working session. Permanent makes every parameter manipulation audible as it happens, so variations can be dialed in by ear. Immediate lets parameters be adjusted while one variation is running, then loaded in at the right moment with a button press. Eight factory-loaded variations exist for every program except Reverb, which gets 16, and the same number of user memory slots is available per program. Recall is a three-step routine — Fix/User, variation number, RCL — and hitting a currently loaded variation number again opens the second bank of eight Reverb programs. The storage procedure for user memories is described as simple and fast.
Maintenance access is well thought out. The important analog circuit cards sit behind that hinged front panel. Folding it down exposes the boards, where all level calibration is done, and it's a fast and simple process. Components are labeled on each board and test points are provided. If a memory error occurs, an LED on the digital board identifies the offending chip. Correction is built in, so a single defective storage unit gets corrected to the proper value rather than taking the program down. The manual supplies schematics for everything needed in case of failure. Reviewers found it clear and concise enough that one reading left them comfortable operating the unit. The block diagrams of the programs drew particular praise.
Reception was split. Recording-Engineer (June 1987, p.56) ran a Hands-On review by Bob Hodas, who came away enthusiastic about some aspects and convinced EMT needed a more careful look at others. He called the 252 probably the most expensive digital reverb on the market and said he expected more for such a high price. He also measured roughly 10dB more noise than he anticipated, which was plain when he connected the outputs to the console with nothing on the inputs. He found the reflections could be too hi-fi and too distinct, interfering with the original signal. On instruments with heavy bass energy or transients, kick drum being his example, the reflections turned problematic. A separate Recording-Engineer (October 1985, p.210) new-products notice, announcing availability through Gotham Audio, described the system as providing voices from one input source with control of chorus depth and rate. It also noted the remote carries 128 memory presets for each of the reverberation and effects programs.
The published technical figures back up the professional positioning: balanced, floating input impedance of minimum 3kΩ, nominal level +6dB with an adjustment range of -10dB to +15dB (0dB = 0.77V), and weighted noise figures per CCIR 468-2 of 70dB quasi-peak and 65dB peak. Those are studio numbers, and the price tag matched them. Collectors chasing a 252 today are chasing a specific point in EMT's digital lineage — the moment the company shrank the box, kept the mono-in/stereo-out architecture of the 251, and pushed the internal math to 20 bits. Whether that trade was worth the asking price in 1987 is a question the original review never fully answered, and it's still the argument that follows this unit around.
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