Teac A-6600 (c. 1975)

Sixty-seven pounds of auto-reverse four-track deck that TEAC built as the top of its four-track line — and the service manual is blunt about what it actually does.

Overview

Start with the number: 30.5 kg, or 67 lbs net, per TEAC's own service documentation. That separates the A-6600 from the rest of the four-track pack. TEAC's literature calls it the top of its four-track deck lineup, and the mass shows where the money went: two capstans, two pinch rollers, and a transport built to pull tape in both directions without favoring either one.

The A-6600 is a quarter-inch, four-track, two-channel stereo deck with forward record/play and reverse *play*. The auto-reverse works off a sensing foil applied to the tape where you want the direction to flip. A delay circuit holds the tape until the capstan motor reaches stable speed before reverse playback begins. TEAC's manual is specific about the mechanism: forward and reverse each get their own capstan, mounted left and right, so tape travel in reverse is governed by the same conditions as forward. The two capstans counter-rotate, which lets the reel turn over cleanly and gives the transport a fast rise out of a direction change.

The drive is a DC servo-controlled capstan motor with AC eddy-current induction motors on the reels. Reel control runs through relay switching because those motors are AC. Tape speeds are 7-1/2 and 3-3/4 ips, and the deck takes reels up to 10-1/2" diameter.

High Fidelity (April 1978, p.61) covered the A-6600 at $1,300 and flagged it as one of the few genuinely new open-reel decks of the moment, noting the full-logic control and automatic reverse as the headline features. That price framing matters: this wasn't a budget deck wearing a fancy badge.

Key Features

Dual Capstan, Dual Pinch Roller Auto-Reverse

Most auto-reverse decks of the period used one capstan for both directions, and tape tension shifted as the reels swapped roles. The A-6600 uses a twin-capstan system instead: separate capstans for forward and reverse, each with its own pinch roller and impedance roller. TEAC's manual states the goal plainly - identical tape-travel conditions in both directions. A tape recorded forward and played back in reverse doesn't sound like a different machine made it.

Reverse is triggered by sensing foil. The delay circuit that waits for capstan speed to stabilize keeps the transport from lurching every time it flips.

Four-Head Stack with Permalloy Heads

There are four heads: erase, record, forward play, and reverse play. The separate forward and reverse playback heads make the auto-reverse mechanical rather than electronic. The separate record and playback heads allow post-record monitoring, so you hear what's actually on the tape as it goes down, not what you're feeding it. TEAC fitted high-hardness permalloy heads, chosen for wear resistance. The manual notes that production-run changes mean early and later machines can differ in minor ways, so head condition is worth checking serial-number-adjacent when buying.

CAL Position on the Monitor Switch

TEAC's own circuit description spends the most words on this feature. Earlier TEAC decks had no CAL position. If you nudged the output control to get a comfortable listening level, the VU meter drifted off the actual recorded level, and you were metering a lie. The A-6600 adds a CAL position to the monitor switch. With it engaged, the meter reads the level recorded on the tape regardless of where the output control sits. A separate TRIM control compensates for level differences between tapes on playback.

LED Peak Indicator and Auto Spacer

An LED peak indicator lights at +10 VU at 19 cm/s and +8 VU at 9.5 cm/s, and the memory circuit holds the indication for 70 ms so short transients don't slip past unrecorded. Auto Spacer is the other convenience. Hit Pause during recording with it engaged and the deck inserts a no-signal gap between roughly 3 and 8 seconds before waiting to resume. For anyone assembling a tape of separate takes, that's useful automation.

Counter Repeat and Reverse-Track Cueing

The counter repeat mechanism works in combination with auto-reverse. Set the counter to 0000 at the point you want repeated and the deck returns from reverse to forward automatically. TEAC also added a 1/3 and 4/2 track selection cueing mechanism. Previously, cueing tracks 1 and 3 was possible, but the reverse tracks (4 and 2) required a tape to access. The A-6600 lets you cue reverse tracks without one.

Bias and Equalizer Switching, Mic Attenuator, Remote Provision

Bias and equalizer switch independently, so owners can match the deck to different tape formulations rather than accepting a single factory compromise. A microphone attenuator handles hot mic signals. The deck also accepts an optional RC-80 remote control unit and RC-350 timer control adapter, both sold separately.

Historical Context

The A-6600 arrived around 1975, though sources disagree on the exact year. Some period material places it in 1978, and the documentation isn't reconciled. TEAC positioned it as the top of its four-track line, a professional-grade machine for the serious hobbyist rather than a studio tool. Contemporary coverage put it up against machines from Tandberg and Revox in performance terms, if not in name recognition. High Fidelity's April 1978 writeup treated it as one of the more interesting new open-reel decks in a market that was already thinning out.

Original pricing is documented two ways and they don't agree: $1,495 from one source, ¥249,000 (around 1977) from another. Neither can be cross-checked against the other, so treat both as reported figures rather than confirmed MSRP.

Collectibility & Value

Working A-6600s typically change hands in the $400-$700 range depending on cosmetics and service history. Fully serviced units, with new rollers and calibrated heads, command the top of that band. A $1,500 asking price has been seen on a listing, but that's an outlier against the general market.

The maintenance list is the usual vintage tape-deck litany. Pinch rollers and idler tires harden or crumble and need replacement. Heads accumulate oxide and want cleaning with isopropyl alcohol plus periodic demagnetizing. Transport grease dries out and causes sluggish operation or motor strain. Power supply and signal-path capacitors age and may need replacing. None of it is unusual, and the deck's modular design plus TEAC's extensive 1970s service network means parts availability is better than average for a machine this old. A replacement dual-bearing pinch roller is still produced for the A-6600, A-6700, and A-6700DX. An 86-page service manual exists, which helps when you're chasing a transport fault.

Units with original packaging, manuals, and accessories are rare and can fetch premium prices. The deck is generally considered reliable and repairable. One owner called it among the finest TEAC decks ever made, which is enthusiasm rather than measurement.