Specifications
Factory figures belong on this page — quoted from Akai's own paper, with the document named beside every number. That rule comes from hard experience: specification tables copied from the web arrive with decades of transcription errors baked in.
There is now a citable source: chapter I of the X-150D service manual, transcribed in full in this library's digital edition. One caveat travels with every figure below — the manual itself is a mirror of a scan that has circulated online since 2008, not factory paper on this bench, so these numbers are Akai's own published claims, not yet independently measured here.
Factory specifications
| Item | As printed | Source |
|---|---|---|
| Style | Portable | SM p. 1 |
| Recording system | Inline 4-track stereo, monaural playback. | SM p. 1 |
| Tape speed | 3 speeds......1-7/8, 3-3/4 and 7-1/2 ips 15 ips optional | SM p. 1 |
| Wow and flutter (playback only) | Less than 0.15% R.M.S. at 7-1/2 ips. Less than 0.25% R.M.S. at 3-3/4 ips. Less than 0.35% R.M.S. at 1-7/8 ips. | SM p. 1 |
| Frequency response | 30 to 23,000 cps (Hz) at 7-1/2 ips. 30 to 18,000 cps (Hz) at 3-3/4 ips. 30 to 9,000 cps (Hz) at 1-7/8 ips. | SM p. 1 |
| Signal to noise ratio | Better than 50 db. | SM p. 1 |
| Output level | 1.228 V (0 VU) at using 1,000 cps (Hz) 0 VU recorded tape. | SM p. 1 |
| Output impedance | 1.5 K.Ohms | SM p. 1 |
| Input level — line input | 50 mV~2.5 V | SM p. 1 |
| Input level — mic. input | 0.5 mV~20 mV | SM p. 1 |
| Input level — DIN. input | 20 mV~25 mV | SM p. 1 |
| Motor | Hysteresis synchronous 2-speed motor. Horse power : 1/100 HP Power ratio : 85% Revolution : 3,000 to 1,500 R.P.M. at 50 cps (Hz) 3,600 to 1,800 R.P.M. at 60 cps (Hz) Condenser capacity : 2.8 μF at 50 cps (Hz) 2.0 μF at 60 cps (Hz) | SM p. 1 |
| Transistor used | 2SC650 (A) ×4 2SC281 (B) ×4 2SC458 (B) ×2 2SC696 (J) (I) (F) | SM p. 1 |
| Reels used | 7", 5", 3" reels | SM p. 1 |
Heads
All three heads are inline 4-track, as printed on service manual p. 1.
| Head | As printed |
|---|---|
| Recording/playback head | Inline 4-track stereo/monaural Gap ...... 0.2 microns Impedance ... 1,000 Ohms at 1,000 cps (Hz) |
| Bias head | Inline 4-track stereo Gap ...... 0.2 mm Impedance ...... 500 Ohms at 60 Kc |
| Erase head | Inline 4-track stereo. Gap ...... 0.2 mm Impedance ...... 300 Ohms at 60 Kc |
The recording/playback head's gap is printed in microns where the other two heads are printed in mm — reproduced here exactly as it appears on the page, not normalized.
What this page still wants
Two things would make this table more than Akai's word for it: figures from period sales literature, to compare the factory's own marketing claims against the service manual's engineering numbers; and the machine's own measured numbers, once the bench gets far enough to run the chapter II procedures — tape speed deviation, wow and flutter, frequency response, and the rest — against this specific X-150D.