Aiwa TP-708

The Aiwa TP‑708 is a compact, portable two‑track mono open‑reel tape recorder from the late 1960s, bridging consumer portability with basic home recording capabilities.

Positioning and era

• Introduced around 1968 as a mains/battery hybrid unit, marketed for dictation, lectures, and casual music use rather than hi‑fi studio work.

Transport and tape format

• Reel size: Up to 4‑inch reels, unidirectional (one direction per track).

• Drive system: Capstan drive with pinch roller; two speeds:
  1⅞ ips
  3¾ ips​

• Track format: 2‑track mono (½‑track), recording one direction on each side of the tape.​

• Heads: Standard 2‑head arrangement (erase + record/playback).​

Electronics and performance

• Circuitry: Fully transistorised with 7 transistors and additional semiconductors for audio amplification.​

• Power supply:
  Batteries: 4 × D‑size 1.5 V cells (6 V DC).
  Mains: 117 V, 60 Hz AC version documented (other voltages likely existed).​

• Output power: 500 mW driving the internal speaker.​

• Performance: Adequate speech intelligibility and modest music at 3¾ ips; not hi‑fi but "very decent" for its size per user reports. AC operation improves stability over battery.​

Acoustic section and monitoring

• Speaker: Single 2.5 × 4 inch oval driver for nearfield monitoring.​

• Basic frequency response tailored to voice/light music; aux output allows connection to external amps for better fidelity.

Controls, I/O, and features

• Transport: Record, Rewind, Play, Stop buttons (no fast‑forward noted).​

• Inputs/Outputs:
  Microphone input.
  Earphone/aux line out.
  Remote control jack.

• Simple level control; no tape counter or advanced features like AVC/tone controls.​

Construction and dimensions

• Size: Compact portable design, roughly 300 × 200 × 100 mm (estimated from similar models; exact varies by listing).​

• Weight: Around 4–5 kg including batteries, with metal/plastic case and carrying handle.​

• Build notes: Robust for travel; die‑cast frame in some descriptions for vibration damping.​

Use and restoration notes

• Ideal for vintage collectors valuing portability; recordings hold up well post‑service.

• Common issues: rubber pinch roller/capstan wear, capacitor aging, belt degradation (if present), switch oxidation. Clean/lube mechanism and recap for reliability.​

Overall, the TP‑708 offers charming 1960s portable performance—simple, durable, and effective for its intended speech/music role when maintained.