Kurzweil 250RMX
The K250's sound in a rack — the expander that turned a flagship keyboard into a studio workhorse.
Overview
The 250RMX is the rackmount version of Kurzweil's flagship K250, and the company's own advertising framed the relationship plainly: the K250 was introduced in 1984 and, per Kurzweil's copy, "set the industry standard for sampling excellence and programming sophistication." The 250RMX carried that engine into a rack chassis for players and studios who wanted the K250 voices without the keyboard. Recording-Engineer (December 1988, p.26) ran the company's line describing the 250RMX as "a rackmount version of the K250" — the two instruments were sold as siblings under the same 250 Series banner.
What the 250RMX actually is, in use, is a sample-playback expander built around Kurzweil's digital sampling technology. The company's marketing leaned hard on the claim that it was the only keyboard manufacturer using "sophisticated mainframe computers to recreate acoustic sounds," and whatever one makes of the salesmanship, the K250 sound library was the draw. The rack version exists so that library could live in a MIDI rig rather than on a dedicated keyboard.
The 250 Series was actively supported rather than frozen at launch. Kurzweil's period advertising and product notes describe a steady stream of updates: portable RAM cartridges to extend memory, a ninth sound library with more promised, and an option for twelve separate outputs for routing individual K250 voices. Version 6.0 software, per Kurzweil's own product notes, streamlined operating functions and added programming control over the company's 1000 Series products, plus a Cycle Mode that let a user play a grand piano patch across a 1000PX and a K250 simultaneously over MIDI — in effect a 36-note polyphonic piano. The same software release added support for Kurzweil's RAM cartridge, expanding the 250/250RMX's internal RAM for longer sampling times, more sequencer data, and more setup data, and Superam II was offered to quadruple the 250's onboard RAM. A Separate Output Kit, QLS (Quick Load System) software for Mac II and IBM PC, and four internal Sound Blocks rounded out the support program.
Demand was strong enough that Kurzweil's own newsletter made a joke of it. Under the heading "DID SOMEBODY SAY 250RMX?", the company confessed it had "kicked production right in the ROMs to meet the demand," reassuring dealers that backorders were on the way. That same newsletter carried a testimonial from programmer Phil Shenale, who used a K250 for film, television, and commercial work and said he wanted to add "one or two 250RMX's" to his rig — a small but telling snapshot of who the rack version was for.
Pricing is the murkiest part of the 250RMX story, and collectors should be careful which figure they quote. A West L.A. Music dealer advertisement listed a "250RMX Fully Loaded" at a $14,995 list price, discounted to $2,995 and then to a $2,499 street price. That gap between list and street is enormous even by the standards of the era, and it says more about dealer discounting and the loaded configuration than about the instrument's nominal cost. Treat any single price figure for this unit with suspicion — it depends heavily on configuration and on which column of the ad you read.
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