Teac X-7RMKII
Teac's six-head bidirectional open-reel deck. It plays both sides of the reel without anyone touching it.
Overview
The X-7RMKII is an 18-kilogram open-reel deck, nearly 39 pounds of capstan motor, reel motors, and steel chassis. Most 7-inch reel decks carry three heads. The X-7RMKII carries six: forward erase, forward record, reverse playback, forward playback, reverse record, and reverse erase. That array lets the deck record and play in both directions without flipping the reel. It is also what separates the X-7RMKII from its sibling, the X-7MKII, which Teac built with a conventional three-head complement.
Teac's own service documentation is careful about this distinction. The mechanical adjustment procedures are written for the X-7RMKII, with a standing note that they apply to the X-7MKII "except for those in relation to the REVERSE direction." The reverse-direction hardware, meaning the extra heads and the FWD/REV change mechanism, is what the R in the model name buys you.
The transport runs at 19cm/s (7-1/2 ips) and 9.5cm/s (3-1/4 ips), and it accepts 7-inch reels. The capstan is driven by a DC brush motor with FG servo. The two reel motors are DC slotless types. Bias frequency is 100kHz. Playback equalization is switchable between NAB and EE at both speeds: 3,180µs + 50µs (NAB) or 3,180µs + 35µs (EE) at 19cm/s, and 3,180µs + 90µs (NAB) or 3,180µs + 50µs (EE) at 9.5cm/s. The EE setting is for high-bias chrome-type tape, and having it switchable on a consumer open-reel deck was not a given in this era.
The X-7RMKII can be operated vertically, horizontally, or at an angle. Teac lists all three positions in the manual, which helps if you have to fit a deck into a shelf that wasn't designed for one. Power requirements vary by market: 100/117/220/240V AC at 50/60Hz for the general export model, with country-specific variants for Europe (220V/50Hz), the U.K. and Australia (240V/50Hz), and the U.S. and Canada (117V/60Hz). Consumption is listed at 77W.
What the Numbers Actually Mean
The wow and flutter figures in the service data show what kind of machine this is. Playback wow and flutter is rated at 0.05% WRMS and 0.10% RMS at 19cm/s, rising to 0.07% WRMS and 0.12% RMS at 9.5cm/s. Record/playback figures are higher, 0.12% RMS at 19cm/s and 0.15% RMS at 9.5cm/s, because the record head adds its own contribution to the chain. These are solid numbers for a bidirectional transport, and they reflect the FG servo on the capstan doing real work. A deck that changes direction has more opportunities for speed instability than one that doesn't.
Signal-to-noise is specified as a minimum, not a typical, and the manual breaks it out by tape type and speed. Playback S/N runs 50 dB minimum at 19cm/s with LH tape, 52 dB minimum with EE tape, 49 dB minimum at 9.5cm/s with LH, and 52 dB minimum with EE. The overall record/playback figures are lower: 48 dB minimum at 19cm/s with LH, 50 dB minimum with EE, 46 dB minimum at 9.5cm/s with LH, and 50 dB minimum with EE. The EE tape advantage shows up in every measurement.
Channel separation is 50 dB minimum at 1kHz, and adjacent track crosstalk is 40 dB minimum at 125Hz. Total harmonic distortion is 0.8% or less at 1kHz. Erase efficiency is 68 dB minimum at 1kHz, measured with an input 10 dB above the specified input level. That is a demanding test condition.
The mechanical service data is where the bidirectional design shows its complexity. Tape speed deviation is 3,000Hz ± 30Hz, with drift held to 15Hz. The FWD/REV tape speed differential is 30Hz, a spec that exists only because the X-7RMKII runs both directions. The FWD/REV change time is 3.5 seconds ± 0.5 seconds, which is how long you wait when the deck hits the end of the reel and reverses itself. The timer activate time is 4 seconds ± 2 seconds. Pitch control offers standard tape speed ± 6% or more.
Reel torque in play mode is 260 ± 40 g-cm take-up with 180 ± 40 g-cm back tension. In fast winding, take-up jumps to 1,100 g-cm while back tension drops to 50 g-cm. Brake torque is 800 to 1,400 g-cm in the forward direction and 500 g-cm or less in reverse, with left/right deviation held to 200 g-cm or less. Fast winding time for a 550-meter (1,800-foot) reel is 150 seconds or less. Pinch roller pressure is 1.35kg to 1.9kg (3.0 to 4.2 lbs).
Inputs, Outputs, and the Practical Stuff
The mic input is specified at -60dB (0.775mV) with a 10kohm impedance, and it will accept a minimum input level of -70dB (245µV). Line input is -12dB (195mV) into 50kohms, with a minimum input level of -22dB (61.5mV). The output is specified at -5dB (436mV) into 10kohms, with a maximum output level of +1dB (0.869V). The headphone output is -24dB (48.9mV) into 8 ohms. These are period-typical consumer levels. The 0dB reference throughout the service data is 0.775V, so if you align the deck with a voltmeter calibrated to a different reference, the manual explicitly notes that compensation is required.
The manual's alignment procedures assume a technician with proper test equipment: an AC voltmeter with input impedance of 1 M-ohm or more, a TEAC YTT-8013 test tape at 35µm thickness, and a correction jig (TEAC part number 5736000100) for aligning the pinch roller spindle to the capstan. The erase head core is supposed to protrude 0.1mm above the moving tape. If it doesn't, Teac's instruction is blunt: replace the head and recheck. The head and tape path alignment procedures are the same for the X-7RMKII and X-7MKII, but the reverse-direction steps only apply to the R model.
Service documentation also includes a full parts breakdown. The speed PCB assembly uses a 2SC536(F) transistor and carbon resistors at ±5% tolerance and ¼ watt. The operation PCB assembly for the X-7MKII uses tact switches and LEDs (SLB-260GG green, SLB-26UR red). The X-7RMKII's switch PCB carries a rotary switch. The in/output terminal PCB assembly lists a 4-pin jack and 39kohm carbon resistors.
Reception and Context
Period coverage of the X-7RMKII in the English-language hi-fi press is thin. The one contemporaneous mention in the archive comes from a 1982 survey of auto-reverse cassette decks, a category piece rather than a full test report, and it does not address the X-7RMKII directly. What it does confirm is the market context: by 1982, auto-reverse was a feature buyers were actively comparing across formats. As HiFI-Stereo (May 1982, p.58) noted in its survey of the auto-reverse market, quick-reverse bidirectional decks such as the GX-F66RC and GX-F44R carried prices of $575 and $475 respectively, while the three-head DR-F7 and DR-F6 with servo-controlled tape tension and Dolby-C listed at $500 and $425. No independent lab measurements, original retail price, or full review of the X-7RMKII has surfaced in the archive. The service manual is the authoritative document here, and it is unusually complete.
Living With One
The X-7RMKII rewards patience and punishes neglect. The six-head array is the reason maintenance costs more than it does on a three-head deck. Every head in the forward and reverse paths needs to be clean, demagnetized, and correctly aligned. The reverse heads are the ones that get forgotten, because they're harder to see and the deck works fine in forward play even when they're marginal. The service manual's alignment procedure is explicit that the reverse direction requires its own set of checks, substituting reverse mode for forward play mode at each step.
The FG-servo capstan motor and the two slotless reel motors are tough, but the belt and pinch roller are wear items, and the bidirectional mechanism adds a change cycle that a one-direction deck never sees. The 3.5-second FWD/REV change time shows this is an electromechanical process, not a software toggle. When it doesn't work, the deck either stops at the end of the reel or reverses with an audible clunk that points to brake torque out of spec.
At 18kg net, this is not a deck you move around casually, and the ability to run it vertically, horizontally, or at an angle helps anyone with limited shelf depth. The 7-inch reel limit is the real constraint. If you need 10-inch reels and the longer uninterrupted takes that come with them, this is the wrong machine. If you want bidirectional recording and playback in a 7-inch format with a six-head transport, the X-7RMKII is one of the few decks that does it.
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