Akai GX-650D

The three-motor Akai that graduated to servo control.

By 1976 Akai had stopped treating servo motors as an exotic feature reserved for the flagship. The GX-650D brought a proper AC-servo closed-loop dual-capstan transport down into a deck you could actually afford to own two of — and it’s the machine in this collection that convinced me Akai’s mid-range, not just its halo models, deserved real attention.

Introduced

c. 1976 · Japan

Track config

4-track (quarter-track) stereo

Speeds

3¾ / 7½ / 15 ips

Motors

3 · AC servo capstan, 2 eddy-current reel

Heads

3 · GX glass & crystal ferrite

Wow & flutter

<0.04% RMS @ 15 ips

Frequency response

30 Hz–30 kHz ±3 dB @ 15 ips

Weight

26.2 kg

SECTION 01

The Merits

The transport is the story here: a closed-loop dual-capstan design driven by an AC servo motor, not a simple synchronous one. That distinction matters more than it sounds — a servo motor holds speed against a feedback signal rather than just following the mains, which is why the wow-and-flutter figure on this deck (under 0.04% RMS at 15 ips) sits well ahead of most Akai decks that came before it.

The GX heads — Akai’s glass-and-crystal-ferrite formulation — are the other half of the pitch. They’re hard enough that head wear stops being something you think about, which isn’t true of the Permalloy decks elsewhere in this collection.

Twin VU meters, a lockable 6-button wired remote, and a transport one long-time owner on a collector forum called ‘one of the better transports Akai used’ round it out. Nothing about it feels like a mid-range compromise.

A servo motor doesn’t just hold speed — it stops you from ever having to listen for whether it’s holding speed.

SECTION 02

The Quirks

No auto-reverse, which surprises people who assume every ‘600-series’ Akai from this era has it — that feature lived on different models. The transport controls are still mechanical push-buttons rather than full solenoid logic, so there’s a satisfying clunk to using it that some decks of the same vintage had already engineered away.

The bigger quirk is the power spec, and it’s not one number: the service documentation lists three distinct variants sold under the same model name — a fixed 120 V/60 Hz version for US/Canada, a fixed 220 V/50 Hz version for Europe, and a genuine 100–240 V, 50/60 Hz switchable version for other export markets. Three different machines, one nameplate.

Belts and idlers show the usual era-typical wear; replacement kits are easy to find and this isn’t a deck anyone should be scared off by.

SECTION 03

The Sound

At 15 ips through the GX heads, this is a genuinely stable, detailed-sounding deck — the three-motor closed-loop transport keeps tension even and pitch steady in a way you can hear on sustained piano or strings, the same test that trips up lesser transports.

SECTION 04

Buying One

If you’re shopping for one, the first thing to check is which of the three power variants you’re actually looking at — the nameplate on the back will say. GX heads mean you can worry less about wear than you would on a Permalloy deck of the same age; budget for a belt and idler refresh regardless of which variant you land on.

How mine runs in the Philippines

Because the capstan is AC-servo rather than simple-synchronous, mains frequency genuinely doesn’t affect this deck’s speed at all — only voltage does. Mine is the multi-range export variant, so it plugs straight into 220 V Philippine mains with just a plug adapter. If you’ve got one of the fixed 120 V US/Canada units instead, you’ll need a step-down transformer regardless of frequency — check your nameplate before you assume.

That’s the whole collection.

All twenty machines in the collection now have their own write-up. Thanks for reading this far — explore the rest of the collection, or start again from the top.