Aiwa AD-3600
A front-loading three-head deck with a double-speed mode, and flutter numbers that held up in the test lab.
Overview
Collectors tend to find the AD-3600 sideways, through a footnote in a magazine test report rather than a spec sheet. The distinguishing feature is a double-speed mode. Alongside the standard 4.8 cm/s compact cassette speed, the deck runs at 9.5 cm/s. That second speed is why most people seek the machine out, because doubling tape speed does real, audible things to the top end and to transport stability. At 9.5 cm/s, the frequency response stretches to 20 Hz - 20,000 Hz. Drop back to 4.8 cm/s and the ceiling comes down to 20 Hz - 16,000 Hz. It's a front-loading, three-head stereo cassette deck. The transport controls are mechanical, with a tape counter to keep your place.
The flutter numbers are what make the AD-3600 interesting to a tape obsessive, more than the double-speed switch. Wow and flutter is rated at 0.04% WRMS at 9.5 cm/s and 0.06% WRMS at 4.8 cm/s. On paper, those look like a manufacturer's optimistic claim. But independent testing backed them up, which is rare for a consumer deck. Audio (September 1981, p.36) ran the AD-3600 through a flutter comparison against a Nakamichi 582. The reviewer reported that the Aiwa decks tested were the best he had seen to that point at delivering low flutter regardless of which cassette was loaded. The test even threw a deliberately poor cassette at the deck, one that had produced readings approaching 0.3% in the Nakamichi. The AD-3600 kept most readings under 0.06%, with plenty at or below 0.04%.
The deck handles Normal, CrO₂, and Metal tape types, and noise reduction is Dolby B. Signal-to-noise ratio is quoted at 62 dB with Dolby B engaged, respectable for the era. A hard permalloy head does record/playback duty. The metering is murky in the surviving documentation. Sources describe either dual analog VU meters or LED peak meters, and the research doesn't settle which the AD-3600 actually had. Check photos of the specific unit rather than trust a single description. A DC servo motor drives the transport, though the exact motor count and model aren't documented.
Physically, it's a wide, shallow, rack-friendly box: roughly 430 mm across, 120 mm tall, and 290 mm deep, at about 5.5 kg. That's a standard-width component that slots into a stack easily, and the weight suggests a transport built with some seriousness. Rewind and fast-forward run a C-60 in approximately 55 seconds.
One caveat applies to the whole page. The specification block this profile draws from isn't cleanly re-attributed line by line to the AD-3600, and no confirmed manufacturer spec sheet turned up in the research. Treat the numbers as provisional. They're consistent with what the period coverage describes, but a buyer should verify against the unit in hand. The flutter story is not provisional, since a magazine test is behind it.
Key Features
Double-Speed Operation at 9.5 cm/s
This is the headline function. Running the tape at 9.5 cm/s instead of the standard 4.8 cm/s buys headroom at the top of the spectrum, with the response climbing from 16,000 Hz to a full 20,000 Hz. It also tightens the transport, dropping wow and flutter from 0.06% to 0.04% WRMS. For anyone dubbing critical material or chasing the last octave, this is the reason to own the deck. It's also what makes the AD-3600 a curiosity. Most cassette decks of the period were locked to one speed.
Hard Permalloy Head, Three-Head Front-Loader
A three-head, front-loading layout with a hard permalloy head means you can monitor off the tape while recording. That's the classic advantage of separate record and playback heads. Permalloy is a durable, well-understood choice for the job. Front-loading keeps the deck stackable and the tape accessible without reaching over the top of a rack.
Dolby B Noise Reduction
Dolby B is the noise-reduction system on board, quoted at 62 dB signal-to-noise with the circuit engaged. It's the ubiquitous consumer format, which means tapes recorded on the AD-3600 play back correctly on virtually anything else, and vice versa.
Normal, CrO₂, and Metal Tape Support
The deck is set up for all three of the major cassette formulations: ferric Normal, chrome-bias CrO₂, and Metal. That matters on a deck with a double-speed mode, because the better tape types are where the extended high-frequency response earns its keep.
Mechanical Transport and Tape Counter
Mechanical transport controls and a tape counter make up the user interface. There's no logic-controlled soft-touch here, and the counter is the only way to find your place on a tape.
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Related Models
- Aiwa ad-f-990 (1983–1984; other sources give 1983–86 and 1983–1989)
- Aiwa ADWX220
- Aiwa AV-50M
- Aiwa AX-7800U
- Aiwa cassette deck