Pioneer RT 707

The Pioneer RT‑707 is a 7‑inch, ¼‑inch, 4‑track/2‑channel stereo reel‑to‑reel deck with a 3‑motor, 4‑head, auto‑reverse (playback‑only) transport built around a direct‑drive capstan, produced roughly 1977–1982 as a mid–high‑fi machine.

Transport and format

• Tape format: ¼‑inch, 4‑track, 2‑channel stereo.

• Heads: 4 total – 2 playback heads (one for each direction), 1 record head, 1 erase head, enabling auto‑reverse playback but forward‑only recording.

• Motors: 3 – 1 AC servo FG‑controlled direct‑drive capstan motor, 2 six‑pole inner‑rotor induction reel motors.

• Reel size: up to 7‑inch (18 cm) reels.

• Tape speeds: 3¾ and 7½ ips (9.5 and 19 cm/s).

• Auto‑reverse: playback‑only, using sensing foil at the tape end; continuous‑play repeat mode can shuttle between counter “0” and tape end.

Audio performance

• Frequency response (NAB EQ):
  At 7½ ips: 20 Hz–28 kHz.
  At 3¾ ips: typically quoted around 30 Hz–20 kHz (or 20 kHz–24 kHz depending on source).

• Wow & flutter: 0.05% WRMS at 7½ ips, about 0.08% at 3¾ ips.

• Signal‑to‑noise ratio: about 58 dB (no noise reduction).

• THD: around 1%.

• Crosstalk / channel separation: ≈ 50 dB or better.

• Erase ratio: >70 dB; bias/erase frequency about 125 kHz.

Electronics and connectivity

• Equalization: NAB at both speeds.

• Inputs:
  Line: 50 mV nominal, ~100 kΩ impedance (RCA).
  Mic: 0.25 mV nominal, 27 kΩ (¼‑inch jack).

• Outputs:
  Line out: 0.45 V at 50 kΩ (RCA, plus DIN on some versions).
  Headphones: front‑panel jack, level derived from line amp.​​

• Semiconductors: about 67 transistors, several FETs and ICs, plus ~47 diodes.

Physical, power, and production data

• Dimensions: roughly 480 × 230 × 356 mm (W×H×D).

• Weight: about 20 kg (≈ 44 lb).

• Power consumption: around 120 W; typical supply ranges 110–120 V and 220–240 V depending on market.

• Production: made in Japan, c. 1977–early 1980s, original list price around mid‑to‑upper mid‑fi (≈ USD $575 / ~1,950 DM).

Functional character (in use)

• Direct‑drive capstan plus dedicated reel motors give very stable speed and gentle tape handling, with no belts in the main transport and minimal long‑term maintenance.​

• Auto‑reverse playback and repeat modes, pitch control (±6%), logic‑controlled transport and dual play‑head azimuth adjustments make it unusually full‑featured for a 7‑inch deck, which is why the RT‑707 is still considered one of the most desirable compact open‑reel machines for serious home listening.