Three Speed Inline 4-Track Reel to Reel Tape Recorder
The cross-field head created a sensation in the tape recorder market by making possible a wide range recording never before heard on any conventional tape recorder.
Using this cross-field head, Akai model X-150D provides a surprising recording performance of 30-23,000 cps at a tape speed of 7-1/2 ips, 30-18,000 cps at 3-3/4 ips and 30 to 9,000 cps at 1-7/8 ips.
What is superior about cross-field recording? How does it differ from typical recording methods as far as construction is concerned?
In the typical recording system, the signal current and the bias current are combined together and applied to the recording head. It is well known that the purpose of bias current is to record, at high sensitivity, a signal applied on the tape, with little distortion and minimizing noise generation. However, the bias current providing such an advantage also has an undesirable character. That is, the wide magnetic field of the bias current affects the recorded signal, resulting in weakening or even erasing the signal. This phenomenon is particularly noticeable at high frequencies.
In the cross-field system, the signal current is applied to the recording head while the bias current is applied to the bias head. These two heads are located in different positions, as determined inter-relatively, so that the magnetic field of the bias will not affect the signal recorded on the tape, even when sufficient bias is applied. This allows the recorded signal to remain on the tape with high fidelity.
Track system: 4-track, 2-channel, stereo/monaural system
Heads: 1 x record/playback, 1 x erase, 1 x bias
Motor: 2 speed hysteresis synchronous
Tape speeds: 1 7⁄8 3 3⁄4 7 1⁄2 ips
Wow and flutter: 0.12% (7 1⁄2 ips)
Frequency response: 30Hz to 23kHz (7 1⁄2 ips)
Signal to Noise Ratio: 50dB
Input: 60mV (line), 0.5mV (DIN)
Output: 1.23V (line)
Semiconductors: 11 x silicon transistors, 2 x diodes, 2 x rectifiers
Dimensions: 340 x 340 x 230mm
Note: optional 15ips
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Reviewed Mar 05th, 2016 by Missel48
Purchased this model in the Asmara, Ethiopia military audio store in 1969. Unit is till functional today; the only maintenance has been belt replacements.
In my opinion, this was one of the best low-priced reel-to-reel recorders of its time.