Member Summary

Sound Rating: 8.5 / 10 # Owners: 4
Relaibility Rating: 8.75 / 10 Views: 623 # Reviews: 3

Member Actions

Improve This Post

Technical Details

Brand: Akai


Category:Super High Fidelity


Electronics:Solid State


Country of Manufacture:Japan

Release dates:1979 - 1983

Original Price: $995

Tracks:1/4 Rec/PB

Speeds: 3 3/4, 7 1/2

Max Reel Size("): 10.5"

Number of heads: 6

Dimension: 19 x 17.4 x 10" (483 x 440 x 256mm)

Head Composition: Ferrite/Glass

Head Configuration: Stereo

# Motors: 3

Auto Reverse?:Yes

Voltage(s): 100v Japan, 110-120v, 220-240v

Outputs: RCA, 1/4" Headphone

Frequency Response:30Hz to 27kHz (3dB 7½ ips)

Wow and Flutter:.03% at 7½ - .04% at 3 3/4 ips

Signal-to-Noise Ratio:better than 62 dB

Sound quality rating:7 / 10

Long-term reliability rating: 8/ 10

Weight: 46.4 lbs (21.0 kg)

Additional Details


The GX635 and 636 were very similar, all having a symmetrical 6-head design (Glass Crystal) which permitted both playback and recording in both directions.
The GX-635D was the first unit in the series (1979) and was very likely Akai’s first recorder with IC logic controlled tape function controls. It had a pitch control function, recording mute and a programmable record timer. Line and mic mixing was also possible with separate microphone and line-in level controls. These controls were fitted with a “memory ring” which rotated when the level was increased but remained in position when decreased, giving a ‘memory’ of the setting. The direct drive, AC servo capstan motor is frequency-controlled.

Akai also marketed a GX-635DB with Dolby B which did not have the timer switch. Both models were also available with a flat black finish but were sold in smaller quantities as silver was still holding greater popularity for audio equipment of the time.


Additional Info

New price in USA $995 (an extra $100 for the Dolby model)
Heads (6) erase: E4-241 (x2), recording: R4-241 GX head (x2), playback: P4-251 GX head (x2)
Motors (3) 1 x AC servo Direct Drive capstan, 2 x eddy current, Direct Drive outer rotor motors (XO24-TD)
Frequency Response  7½ ips: 30Hz to 27kHz – 3¾ ips: 30Hz to 25kHz  (3dB)
Signal-to-Noise Ratio 62 dB
Wow and Flutter 0.03% at 7½ ips – 0.04% at 3 3/4 ips
Rewind Speed 120 seconds for a 1800 ft tape
Distortion  0.4%  Inputs: Mic: 0.25 mV. Line: 70 mV impedance 100 Kohm. DIN: 2mV / 10Kohm
Outputs  Line: .775 / 20 Kohm.
Headphones  100 mV at 8 ohms. DIN 0.3V
Real Time Counter  99min. 59 sec.
Pitch Control +- 6%


Excellent fiability and sound. Works perfectly since 1985. No parts changed. 
Sound: 10
Performance: 10
2 years ago

Service Report

No Service Report yet.

Leave A Review:

Report Inaccuracies on Akai GX-635D

You need to be logged in for this feature to work.