Akai X-100D
A deck-only version of the M8, priced for people who already owned the amplifier — and built around a head that made slow tape speeds sound fast.
Overview
The X-100D was Akai's way of selling the M8's tape transport to customers who didn't need another pair of speakers in the living room. Where the M8 was a complete stereo machine with vertical centre speakers, the X-100D was the deck version for people already set up with their own amplifier system — Akai's own advertising made the distinction explicit, quoting the X-100D at 99 guineas against the M8's 136. Studio Sound (October 1966, p.16) surveyed current stereo tape recorders and put the UK price at £103 19s., describing it as a version of the M8 introduced alongside the X-PKI battery portable and the 1700 stereo.
The headline technology was Akai's Crossfield head, and the advertising leaned on it hard. The pitch was that the Crossfield design let the machine record frequencies up to 18,000 cps at a tape speed of only 3¾ inches per second, which in practical terms meant four hours of recording on a single 1,200 ft reel — a real saving in tape costs for anyone doing long sessions. The same advertising listed the rest of the package: sound-on-sound recording, automatic shut-off, high-speed forward and rewind, four speeds, a hysteresis synchronous motor, a built-in tape cleaner, and vertical or horizontal operation.
The published specification, as printed in Studio Sound's October 1966 survey of current stereo tape recorders, is unusually complete for a machine of this vintage. Tape speeds were 15, 7½, 3¾, 1⅞ and 1½ ips — five speeds, not four, which suggests the advertising copy was counting the ones most buyers would actually use. Wow and flutter was quoted at 0.15% RMS, and frequency response at 30 c/s–25 kc/s ±3 dB. Spool capacity was 7 inches, weight 30 lb, and dimensions 13½ × 13½ × 9 inches. Output was taken from preamplifiers rather than from a built-in power stage, which is exactly what "deck version" meant in practice. The feature list repeated the advertising: Crossfield bias, FM multiplex recording.
That FM multiplex line is worth pausing on. Studio Sound's survey (October 1966, p.16) devoted considerable space that month to the problem of stereo radio broadcasting and the whistle generated by beating between a recorder's bias signal and the 19 kc/s pilot tone. The magazine noted that many tape recorders were understood to be incapable of making whistle-free copies of pilot-tone transmissions, whether dubbed in mono or in stereo, and that it was difficult to say at the time whether all recorders other than those specifically adapted would be prone to it. Akai listing FM multiplex recording as a feature on the X-100D was a direct answer to that concern — a claim that this machine had been adapted for the new stereo broadcasts. Whether it fully delivered is not documented in the surviving literature.
What the record does show is how quickly the model was superseded. Studio Sound (May 1968, p.25), reporting from Audio Fair '68, noted that the Model X-150D superseded the X-100D as a stereo tape unit. That gives the X-100D a commercial life measured in roughly two years, which is short even by the standards of mid-Sixties tape hardware. It also explains why the X-100D turns up less often than its M8 sibling — the deck-only variant was always the narrower sell, and it was replaced while the M8's formula was still being mined.
For collectors, the X-100D is a specific proposition. It is not the machine to buy if you want a self-contained reel-to-reel that makes sound on its own; it has no output power stage and no speakers, and it needs an amplifier to be of any use. What it offers instead is the Crossfield transport and the five-speed flexibility in a smaller, lighter package than the 47 lb M8 — 30 lb against 47 lb, and 13½ × 13½ × 9 inches against the M8's larger cabinet. The 0.15% RMS wow and flutter figure is respectable for a machine of this class and era, though it is a manufacturer's claim rather than an independently measured number. The 30 c/s–25 kc/s ±3 dB response is the kind of figure that looks generous until you remember it is quoted at 7½ ips and that the ±3 dB tolerance is doing a lot of work at the extremes.
The practical caveats are the usual ones for a 1966 Akai. The Crossfield head is the heart of the machine and the reason it exists; a worn or damaged Crossfield head is not a part you source at the corner shop, and it is the single component most likely to determine whether a given example is worth restoring. The five-speed transport with its hysteresis synchronous motor is robust, but the belt-and-idler path in any machine of this age will need attention, and the built-in tape cleaner is a nice period touch that does nothing for you if the rest of the transport is tired. The deck-only configuration also means there is no built-in amplification to mask transport noise or head wear — you hear what the machine is doing.
Values are not well documented for the X-100D specifically, and it would be dishonest to pretend otherwise. It sits in the shadow of the M8, which is the model collectors know and which commands the attention. The X-100D's case rests on the Crossfield head, the five speeds, and the fact that it is a lighter, simpler machine to live with if you already have a good amplifier. Buyers should expect to pay less than for an M8 in comparable condition, and should budget for head evaluation before anything else. Original price was 99 guineas in the UK, or around £95 according to Studio Sound's pre-launch estimate — a meaningful sum in 1966, and a reminder that this was never a budget machine, just a more specialised one.
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