AEG/Telefunken Magnetophon M28

The AEG Telefunken Magnetophon M28 is a professional studio-grade open-reel tape recorder from 1967–1972, produced by Telefunken under AEG's Magnetophon division in Germany. Known as the "workhorse" of German broadcast and recording studios, it featured robust construction, solid-state electronics, and exceptional mechanical reliability that earned it a legendary reputation among engineers.

Key Technical Specifications

• Track System: 2-track stereo / half-track mono (¼-inch tape)

• Tape Speeds: 7½ ips (19 cm/s), 15 ips (38 cm/s), 30 ips (76 cm/s)

• Maximum Reel Size: 10.5 inches (26.7 cm) NAB hubs

• Heads: 3-head configuration (erase, record, playback) with permalloy laminations

• Motors: 3-motor transport — dual capstan system (hysteresis synchronous capstans + reel motors)

• Frequency Response: 30 Hz–20 kHz (±2 dB) at 15 ips; extended range at 30 ips

• Wow and Flutter: <0.12% at 15 ips (broadcast standard)

• Signal-to-Noise Ratio: >60 dB (CCIR weighted)

• Total Harmonic Distortion: <1% at 0 VU levels

• Electronics: Solid-state modular amplification with professional-grade preamps

• Inputs/Outputs: Balanced XLR connectors, DIN sockets for German broadcast compatibility

• Equalization: NAB/IEC switchable with tape-type calibration

• Features:
  Electronic tension control for consistent tape path
  Remote control capability
  Front-panel bias/EQ calibration
  Variable speed operation (±10%)

• Power Requirements: 220–240 V AC, 50/60 Hz

• Dimensions: 483 x 160 x 409 mm (19" rackmount standard)

• Weight: ~35–40 kg (77–88 lbs)

Design and Build Context

The M28 was engineered for continuous professional duty in radio stations, TV post-production, and record plants. Its dual-capstan transport maintained constant tape tension across the entire reel, eliminating the speed variations common in single-capstan consumer decks. The solid-state electronics provided clean amplification with low noise floor, while the mechanical design prioritized longevity over convenience.

Variants:

• M28A/B/C: Progressive updates with refined electronics

• Rackmount versions for studio integration

• Often paired with external Telefunken mixers and monitor amps

Priced as broadcast equipment (~DM 6,000+ new), the M28 competed with Studer A80 and Ampex models but distinguished itself through German precision engineering. Contemporary reviews praised its "hard as a rock" reliability and transparent sound.

Modern Status 

Rare collectibles today; restoration focuses on recap of solid-state boards, pinch roller replacement, and head alignment. Among Telefunken's most sought-after professional decks, sitting between the earlier M10/M15 and later M20 computational models in the evolutionary chain.