Hitachi D-5500 (c. 1979)

The Hitachi D-5500 is a stereo cassette deck from 1979. Its big feature was ATRS, Hitachi's microprocessor-based automatic tape calibration. Load a standard hi-fi cassette and the deck measured that tape's bias and sensitivity, adjusted itself in under 20 seconds, and stored the results in one of three memories so the same tape type could be recalled next time. Hitachi's own marketing made a point that this worked with any normal brand tape, not the cheap bargain-bin stuff. If you didn't want to wait for calibration, the deck defaulted to factory presets for Hitachi's own UD-ER and UD-EX cassettes.

The transport was solenoid-controlled with light-touch pushbuttons. Dolby NR was switchable with or without a 19-kHz FM MPX filter. HI-Fi-Stereo-Buyers (September 1979, p.55) spotlighted the deck, and HiFi/Stereo Review (July 1979, p.51) ran a full lab report. Measured response was 30-15,000 Hz ±1.5 dB in manual and 20-18,000 Hz +1.5/-3 dB with ATRS. Wow/flutter was ±0.05%. Tape speed ran 0.7% fast at the start of a C-60 and settled to 0.5% slow at the end. The review also noted the deck accepted hot recording levels: +6 dB for TDK AD, +4 to +5 dB for Hitachi UD-EX, and +4.5 to +6.5 dB for Sony FeCr.

Beyond those period reviews, the record is thin. The D-5500 appears to have been a capable, forward-looking deck that never gained much of a collector following. Little else is documented about its production or market life.