Grundig TK 47

The Grundig TK 47 (also known as TK47 or TK 47 Stereo in export markets) is a high-end mid-1960s open-reel (reel-to-reel) tape recorder produced by Grundig Radio-Vertrieb in Fürth, Germany. Manufactured primarily from 1964 to 1966, it was Grundig's flagship stereo model of the era, aimed at audiophiles and serious home users. It was electronically very similar to the quarter-track TK 46 but featured half-track stereo heads (2-track stereo), allowing for higher signal levels, lower noise, and stronger dynamics on standard tape.

The TK 47 was priced originally around 898 DM (a premium consumer figure, equivalent to roughly £90–110 in export markets), making it one of Grundig's most advanced stereo recorders in the TK series. It gained legendary status among vintage collectors for its three-head design (erase, record, and separate playback), real-time off-tape monitoring, wide frequency response, low wow & flutter, and excellent stereo imaging with built-in amplifiers and speakers.

Key Technical Specifications

Track System: 2-track (half-track), 2-channel stereo / monaural (stereo record/playback; monaural operation also supported; records on upper and lower halves of tape in one direction for stereo, or full-track mono)

• Tape Speeds: Three speeds — 19 cm/s (7½ ips), 9.5 cm/s (3¾ ips), and 4.75 cm/s (1⅞ ips); switch-selectable (triple-speed capability offered high-fidelity music recording at 7½ ips, balanced use at 3¾ ips, and extended runtime at 1⅞ ips)

• Reel Size: Maximum 7 inches / 18 cm (standard for high-end domestic recorders of the era; supports NAB/international hubs)

• Heads: 3 heads — separate erase, record, and playback (permalloy construction; allows off-tape monitoring during recording, a major advantage over 2-head designs)

• Motors: 1 motor (capstan drive; single-motor design with mechanical reel assistance; high-quality induction motor typical of mid-1960s premium consumer machines)

• Drive System: Mechanical transport with push-button controls; constant tape speed; foil-sensing automatic stop at tape end; basic tension regulation suitable for standard and thinner tapes; additional features include superimposition (sound-on-sound overdubbing), mixing facilities, synchronous recordings, and remote control socket in some configurations

• Frequency Response (all ±3 dB):60 Hz – 15 kHz at 7½ ips
  60 Hz – 13 kHz at 3¾ ips
  60 Hz – 10 kHz at 1⅞ ips (excellent for the era, especially at 7½ ips; among the widest responses in Grundig's lineup)
  

• Signal-to-Noise Ratio: Better than 50–55 dB (weighted; very good for mid-1960s consumer stereo, aided by separate playback head and low-noise tube circuitry)

• Wow & Flutter: Less than 0.1–0.15% at 7½ ips; less than 0.2% at slower speeds (outstanding for domestic use; among the lowest figures in Grundig's 1960s models)

• Equalization: IEC/CCIR/European standard for the period (some export versions note NARTB compatibility)

• Inputs:Microphone: Low-level (~1.5 mV / 1.5 MΩ; dynamic mic via DIN or proprietary socket; often supplied external mic)
  Line/Radio/Diode: High-level (~100 mV / 1 MΩ or similar; via DIN connector; Grundig 5-pin standard)
  Phono/Grammophon: Additional high-level input for record players
  

• Outputs: Built-in loudspeakers (2 × Superphon 6″ × 4″ high-flux elliptical permanent-magnet dynamic type); low-impedance ext. speaker; high-impedance line out (600 mV / 15 kΩ stereo preamp output for external amplifiers) via DIN socket; output power 2 × 3–4 watts (internal stereo amp)

• Power Supply: Alternating Current (AC) mains — 110; 130; 220; 240 V (multi-voltage taps for export); power consumption around 55–80 W; no battery option (mains-only domestic/portable hybrid)

• Dimensions: Approximately 510 × 400 × 210 mm / 20.1 × 15.7 × 8.3 inches (W × H × D) — larger suitcase/portable form factor with handle

• Weight: Approximately 20 kg / 44 lbs — substantial due to metal chassis, transformers, tubes, and stereo components

• Electronics: Valve/tube-based (typically 8 tubes): 2× EF86 preamp (dual for stereo channels), ECC81 phase splitter/driver, EL84 output (push-pull stereo capable), EM84 magic eye level indicator; diodes/metal rectifiers for power supply

• Other Features: Magic eye (EM84) recording level indicator (glow for level monitoring); mechanical tape counter; automatic tape-end stop; pause function; superimposition (sound-on-sound); mixing facilities; synchronous recordings; remote control socket; recording time up to 8–16 hours total (depending on speed, tape thickness, and track usage) on 7-inch reels with long-play tape

Design and Performance Notes

The TK 47 was a high-performance stereo recorder with a focus on fidelity and versatility: half-track stereo provided higher signal levels and lower noise than quarter-track, while the three-head design enabled real-time off-tape monitoring during recording, a significant upgrade over 2-head models. Triple speeds offered exceptional flexibility—7½ ips for near-professional music fidelity (wide bandwidth, excellent transients), 3¾ ips for balanced domestic use, and 1⅞ ips for maximum runtime on speech/dictation. The tube circuitry delivered a rich, warm, dynamic tone with superior clarity, imaging, and extension—modern vintage ratings place it around 8/10 for sound (one of the finest stereo Grundig recorders of the 1960s) and 7–8/10 for build reliability/durability.

The drive mechanism was robust and precise, with additional features like mixing, superimposition, and remote control enhancing creative use. Common long-term service needs include:

• Tube replacement/check (EF86 microphonics; EL84 output wear)

• Cleaning heads, capstan, pinch roller, and tape path

• Replacing electrolytic capacitors (leakage common after 60+ years)

• Lubricating mechanisms and checking drive belts/pulleys

• Magic eye alignment and rectifier checks

Historical Context

The TK 47 was part of Grundig's foundational 1950s–1960s TK series that popularized open-reel recording in Europe and export markets. It followed models like the TK 35/TK 40 and preceded later multi-speed/stereo machines (TK 14x, TK 24x, etc.). Surviving examples are highly sought-after by collectors today, often prized for their outstanding audio performance and condition due to robust construction, but most require tube and capacitor restoration for reliable operation. They represent a pinnacle in vintage tube-era open-reel collecting, especially for those interested in mid-1960s German audio engineering and high-performance half-track stereo designs with three-head monitoring.