AEG/Telefunken Magnetophon M55

The AEG-Telefunken Magnetophon M55 (also known as Magnetophon 55 or M 55) is a mid-1960s consumer mono reel-to-reel tape recorder, produced approximately 1964–1968 (manufactured in Germany by Telefunken under the AEG-Telefunken brand following the 1967 merger). It belongs to the classic KL-series (Koffer-Lautsprecher = suitcase with loudspeaker) of portable Magnetophon models, designed as a compact, battery/AC-powered mono recorder for home, travel, dictation, or field use. The M55 was a popular mid-range portable of its time, emphasizing simplicity, reliability, and integrated speaker for standalone operation.

This was a half-track (2-track) mono recorder (some listings confirm quarter-track mono compatibility), focused on voice clarity and basic music recording rather than hi-fi stereo performance.

Key Technical Specifications

• Recording/Playback System — Half-track (2-track) mono; records/plays in one direction (tape flip for reverse); mono compatible; basic overdub possible.

• Tape Speeds — Single speed:3¾ ips (9.5 cm/s)
  

• Reel Size — Up to 5 inches (13 cm) diameter (compact for portability; some units accept 7" with care).

• Frequency Response (approximate):At 9.5 cm/s: 60 Hz – 12,000–14,000 Hz (±3 dB) Adequate for voice, speech, dictation, and basic music on small reels.
  

• Wow & Flutter — Approximately 0.25–0.35% weighted at 9.5 cm/s (typical for portable single-motor design).

• Signal-to-Noise Ratio — Better than 45 dB (standard for mid-1960s transistor mono portable).

• Heads — 2 heads: combined record/playback (permalloy) + erase head.

• Drive System — Single motor (synchronous or induction type); belt or idler mechanism; mechanical brakes; fast wind/rewind.

• Electronics — Fully transistorized (typically 8–10 transistors); printed circuit board amplifier.

• Amplification & Speakers — Built-in mono amplifier; internal permanent magnet dynamic loudspeaker (elliptical or round); output power ~0.5–1 W (personal monitoring).

• Inputs —Microphone (low-level).
  Radio/line/pick-up (higher level).
  DIN-style connectors.
  

• Outputs —Line out.
  Internal speaker.
  Headphones possible.
  

• Power — Batteries (typically 6 × 1.5 V = 9 V) or external AC adapter/charger; also car adapter compatible in some configs.

• Build & Dimensions — Compact portable metal/plastic case with carrying handle; approx. 280 × 80 × 280 mm (11 × 3.1 × 11 inches); weight ~3–4 kg (lightweight and portable).

• Manufacturing — Germany (Telefunken/AEG-Telefunken).

Performance & Legacy Context

The Magnetophon M55 was a practical mid-1960s portable mono deck—offering single-speed operation, transistor reliability, and battery/AC flexibility for field, travel, or home use. It delivered decent clarity for voice/journalism, dictation, or basic music dubbing at 3¾ ips on small reels, with acceptable dynamics for its intended purpose. As a mono portable, it prioritized convenience and portability over hi-fi stereo performance.

Common issues today: Belt/idler hardening, dried electrolytic capacitors, transistor aging, dirty heads, mechanical wear (especially on portable transport), and battery compartment corrosion (if stored with old cells). Restorations are straightforward—many units revive well for vintage portable mono use. Service manuals available (Radiomuseum, Elektrotanya—German originals with schematics and alignment).

Compared to siblings:

• Magnetophon 300 series — Compact mono portables (M300/M302/M55 as entry-to-mid-level models).

• Higher models (e.g., M207/M230/M250) — Stereo, three-head, three-speed.

• M55 — Battery-powered mono portable with single-speed focus.