Soundcraftsmen RP2212
A ten-band-per-channel graphic equalizer that promised to flatten any room to ±2 dB, and asked you to trust your own ears to do it.
Overview
The pitch was simple: two cables into your receiver's tape-monitor jacks, a step-by-step instruction record, and a few minutes of your time. Soundcraftsmen's own advertising for the RP2212 claimed that with nothing more than your ears you could "tune" the frequency response of a stereo system and room environment to a flat ±2 dB. The copy called the result an acoustically-perfect concert hall. That was marketing, and collectors discount it accordingly. But the hardware under the walnut-grained case was serious enough to back up a good deal of the claim.
The core of the RP2212 is its equalizer section. It has ten octave-band controls per channel, centered at 30, 60, 120, 240, 480, 960, 1920, 3940, 7680, and 15,360 Hz, each with 12 dB of boost and 12 dB of cut. Octave spacing like this gives broad strokes, enough to chase down room nodes and speaker anomalies without the fiddly narrow-band work of a parametric.
The published numbers read like a company confident in its circuit design. High-level frequency response is quoted at ±1/4 dB from 5 Hz to 100 kHz, with total harmonic distortion below 0.05% at 1 volt (typically 0.01% at 1 volt). Signal-to-noise is listed as 100 dB below full output. Those figures count when the equalizer sits in the tape loop of an otherwise clean system, since a noisy EQ is worse than no EQ. The company also made much of the parts inside: military-grade G-10 glass-epoxy circuit boards and low-noise selected carbon-film resistors, along with separate power supplies for the phono and equalizer sections. Whether that makes it sound better is a matter of debate among collectors. It does make a forty-plus-year-old unit still serviceable today.
If you're shopping the RP-series, the RP2212 is the model with the LED test lights, which worked like a VU meter for each output and input. Soundcraftsmen built a small family around this chassis, and the differences between them are almost entirely about features rather than sonics. The company's own literature describes the RP2204 as the same unit minus the LEDs, and the 20-12A strips out both the LEDs and the front-panel Tape Equalize switching. Buyers who don't care about the lights can save money on a sibling. Buyers who want the full-feature version should confirm they're getting an RP2212, because the model numbers are easy to confuse and the cosmetics are nearly identical.
The front panel also carried "zero-gain" balancing controls for left and right, continuously variable. They were meant to contour an incoming signal to the desired response while putting out an equalized signal at roughly the same level as the input. That means you can shape tone without the whole system jumping in volume every time a slider moves. A variable master volume control let owners match the unit's output to their amplifier.
Pricing moved around during the RP2212's run, as it did across the whole Soundcraftsmen line. Early advertising listed the RP2212 at $349.50, and by late 1977 the suggested price had climbed to $369.50, cabinet or rack mounts included. The unit shipped in a walnut-grained case measuring 7¼ by 20 by 11¼ inches deep, at a shipping weight of 28 lbs. That is a lot of metal and wood. Soundcraftsmen backed it with a two-year parts-and-labor warranty and built it in Santa Ana, California.
Audio (October 1974, p.118) included the RP2212 in its equalizer coverage of the period, and the unit turns up repeatedly in the magazine's advertising pages through the mid-1970s — a sign of how aggressively Soundcraftsmen pushed equalization as a category rather than just a product. The company's argument, made across those pages, was that everyone upstream in the recording chain already uses equalizers to make music sound the way they think it should, so the listener deserves the same tool to make the final adjustment. It's a persuasive framing, and it's also the honest one: a graphic EQ is a room-correction and taste-correction device, not a magic wand.
Today the RP2212 is a well-built American equalizer with real parts inside and a feature set that still does useful work in a modern system. Patching one into a tape loop remains a cheap way to tame a bright room or a boomy speaker placement. The usual caveats apply: sliders get scratchy, the LED lamps can fail, and any unit this old should have its power supply checked before it goes into a prized system. Buyers should expect to pay well under the original asking price, and should verify which RP-series variant they're looking at before handing over money.
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