Akai GX-635D
Not much is documented about the Akai GX-635D. There are a handful of period advertisements and one technical review. What survives points to a 10½-inch reel-to-reel deck that Akai marketed as the first with auto-reverse recording and playback on that size of reel. HiFI-Stereo (April 1979, p.121) ran an advertisement for this feature alongside feather-touch solenoid controls, a pitch control adjustable ±6%, and a timer-start switch for both record and play modes. The same ad mentioned three precision heads. It doesn't say whether that means erase/record/playback or a dedicated playback head.
The microphone input needed just 0.024 mV to reach 0 dB on the meters, and it overloaded at 55 mV. Distortion at the 0-dB reference level measured between 0.2 and 0.4 percent, depending on tape formulation and speed. The 3% distortion point came at an input level of +9 to +10 dB. Signal-to-noise ratios stayed within a few decibels of each other regardless of tape type. The reviewer found the meters slow, underreading by 20 to 30 percent relative to true VU standards. He also noted that the maximum recording level seemed set conservatively below what contemporary tapes could handle.
No original price, production years, or service documentation have been traced.
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