The 300-series are older than the 200-series; strange but true. They are all 3 motor models and some of them have the cross field recording system. The first 300 model dates from the early 60's and is probably the 330. This one is only a mechanical set with no audio part inside. Sometime later came the X-300 and X-330D which used the extra Crossfield Recording head for the bias.
The last model from the 300-series is the GX-370D, which is a 1973-1974 model. Together with the GX-365D from about 1971, these are the only 300 Series models with GX heads. In fact the GX-365D was the first set with the world famous Glass and Xtal Ferrite Heads, and it dates from 1971.
Because of their age and rarity, not much is known about the oldest models except for their specifications and some pictures I have collected during the last couple of years. Most of the models from the 300-series are solid state sets. The X-300D was probably the first Akai set made for playing 10.5" reels without using an extra set of adapters. The X-330D was its successor.
The GX-370D is the last set from the 300-series. It's model number suggests it might be the successor of the GX-365D, which is true in a certain way, although the technique used in the GX-370D is different and is more like the GX-280D/GX-285D sets. The GX-370D is the first Akai deck which could record in both directions, although the tape guide mechanism is asymmetrical. During playback a continuous reverse cycle is possible since this set has two reverse sensing poles.
It has 2 GX combination heads ('combo heads') and one GX playback head on a moving platform, just like the older GX-365/D. Other than the GX-365D the GX-370D has a servo controlled, direct drive capstan. It has 'only' 6 relays on the syscon board which work on 24 V DC.
The GX-370D lacks the Reverse-o-Matic, but the Compute-o-Matic (see GX-365D) function is present, although this set was the last in line to have this COM feature. This deck has easy to pull out pcb's, which differ from those used in the GX-365D. There's also an sound on sound and an auto shut off feature on board.
Its VU meters are large and they are similar to those used in the GX-260D. The tape function buttons are very uncommon. They look like they are mechanical push down buttons, but they are illuminated feather touch buttons.
I only recently found out there are two different versions of the GX-370D: The 1973 edition (see pic.) has an auto shut off function, the 1974 edition has a reverse selector in stead for either a single loop or continuous play. The GX-370D has not been available with a built in main amp.
Track system: 4-track, 2 channel stereo system
Tape speed: 3.75 ips and 7.5 ips
Total Wow and Flutter: Less than 0.07% @ 7.5 ips.
Frequency response: 30 to 26,000 Hz +/- 3 dB @ 7.5 (Akai S.R.T. tape) 30 to 22,000 Hz +/- 3 dB @ 3.75 ips 30 to 24,000 Hz +/- 3 dB @ 7.5 ips (regular tape) 30 to 19,000 Hz +/- 3 dB @ 3.75 ips
S/N ratio: Better than 50 dB @ 7.5 ips
FFWD/RWD time: 68 sec. using a 1200 ft. tape @ 60 Hz, 83 sec. @ 50 Hz
Main motor: SCM2-24
Reel motors: Eddy Current outer rotor motor; model: 24X0-II
Erase Head: RE4-1 (combo head x2)
Recording head: RE4-1 (combo head x2)
Playback head: P4-200
Dimensions: 503 (H) x 445(W) x 252 (D) mm.
Weight: 25.5 kg.
Power consumption: 130 W.
Listed new: $ 1250.00 in 1973