Grundig TK 50

The Grundig TK 50 (also listed as TK-50 or TK 50 in some markets, with variants like TK-54/TK-55 sharing similar designs) is a late-1950s open-reel (reel-to-reel) tape recorder produced by Grundig Radio-Vertrieb in Fürth, Germany. Manufactured primarily from 1959 to 1961, it was a compact, mid-range mono domestic/portable machine aimed at home users, radio enthusiasts, and hobbyists seeking reliable performance with improved features over earlier TK models (e.g., TK 20–TK 25 series).

The TK 50 was priced originally around 610 DM (a mid-to-upper consumer figure), positioning it as a step up from budget models while remaining accessible. It was valued for its dual-speed capability, push-button controls, and solid audio quality, making it suitable for radio dubbing, family recordings, or light music.

Key Technical Specifications

Track System: 2-track (half-track), single-channel monaural (monaural record/playback; records on upper half of tape in one direction, lower half in reverse)

• Tape Speeds: Two speeds — 9.5 cm/s (3¾ ips) and 19 cm/s (7½ ips); switch-selectable (higher speed for improved fidelity and detail)

• Reel Size: Maximum 18 cm (7 inches); commonly used with 13–18 cm reels; supports standard NAB/international hubs

• Heads: 2 heads — combined record/playback head + erase head (permalloy construction; no separate playback head or off-tape monitoring)

• Motors: 1 motor (capstan drive; single-motor design with mechanical reel assistance; reliable induction-type motor typical of late-1950s 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

• Frequency Response: Approximately 50 Hz – 14,000–16,000 Hz (at 19 cm/s; respectable for a dual-speed mono recorder of the era, with good clarity and extension for voice and music)

• Signal-to-Noise Ratio: ≈45–55 dB (typical; good for mid-century consumer mono, aided by quality tube design)

• Wow & Flutter: ≈0.2–0.3% (acceptable for domestic use; single-motor designs had tolerable variations)

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

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

• Outputs: Built-in loudspeaker (elliptical permanent-magnet dynamic type); line out via DIN socket; output power ≈2.5–4 watts

• Power Supply: Alternating Current (AC) mains — 117; 150; 200; 220; 240 V (multi-voltage taps for export); power consumption around 55–80 W; no battery option (mains-only domestic/portable hybrid)

• Dimensions: Approximately 380 × 200 × 340–380 mm / 15 × 7.9 × 13.4–15 inches (W × H × D) — compact suitcase/portable form factor with handle

• Weight: Around 10–12 kg (22–26 lbs) — portable yet substantial due to metal chassis, transformers, and tubes

• Electronics: Valve/tube-based (typically 5–6 tubes; common complement includes EF86 preamp, ECC81 phase splitter/driver, EL84 output (push-pull), EM84 magic eye level indicator; metal rectifier for power supply)

• Other Features: Magic eye (EM84) recording level indicator (glow for level monitoring); mechanical tape counter; automatic tape-end stop; pause function; recording time ≈60–120 minutes total (depending on speed and tape thickness) on 7-inch reels with standard tape

Design and Performance Notes

The TK 50 was a refined mid-range domestic recorder with a focus on versatility and sound quality: dual speeds provided flexibility—7½ ips for higher fidelity (better transients and extension) on shorter reels, and 3¾ ips for longer runtime. The tube circuitry delivered a warm, musical tone suitable for radio dubbing or home entertainment, with improved frequency response over earlier single-speed models—modern vintage ratings place it around 6–7/10 for sound (solid mono performer) and 7–8/10 for build reliability/durability.

The drive mechanism was durable and straightforward, with minimal electronics complexity. 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 50 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 25/TK 30/TK 35 and preceded later multi-speed/stereo machines (TK 14x, TK 24x, etc.). Surviving examples are collectible today, often in good cosmetic condition due to robust construction, but most require tube and capacitor restoration for reliable operation. They represent an accessible entry into vintage tube-era open-reel collecting, especially for those interested in late-1950s/early-1960s German audio engineering and dual-speed mono designs.