Grundig TK 145

The Grundig TK 145 (also known as TK145 or TK 145 de Luxe / Automatic in some variants) is a late-1960s open-reel (reel-to-reel) tape recorder produced by Grundig Radio-Vertrieb in Fürth, Germany. Manufactured primarily from 1968 to 1973, it was a budget-oriented solid-state mono machine aimed at casual home users, students, and hobbyists for basic voice, radio dubbing, or light music recording/playback. It featured quarter-track mono recording for extended playtime on standard reels, push-button controls, and automatic recording level control (AVC/"Magic Ear" in Automatic variants).

The TK 145 was priced originally around £40–50 in export markets (equivalent to roughly 400–500 DM in Germany), making it one of Grundig's most affordable open-reel models in the late 1960s/early 1970s. It was valued for its simplicity, reliability, and decent performance for its class, though it was not a high-fidelity audiophile machine.

Key Technical Specifications

Track System: 4-track (quarter-track), single-channel monaural (monaural record/playback; records on one quarter-track per pass, allowing four tracks total on standard tape by flipping reels twice)

• Tape Speeds: Single speed — 9.5 cm/s (3¾ ips / 3.75 inches per second; no multi-speed capability, optimized for domestic runtime and basic fidelity)

• Reel Size: Maximum 7 inches / 18 cm (some sources note practical max of 6 inches; commonly used with 5–7 inch 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; quarter-track design requires careful alignment for track compatibility)

• Motors: 1 motor (capstan drive; single two-pole motor with mechanical reel assistance; reliable induction-type motor typical of late-1960s/early-1970s budget consumer machines)

• Drive System: Mechanical transport with push-button controls (piano-style keys for play, record, stop, fast forward/rewind); constant tape speed; foil-sensing automatic stop at tape end; basic tension regulation suitable for standard tape

• Frequency Response: 50 Hz – 12.5 kHz (±3 to –5 dB at 3¾ ips; respectable for a single-speed entry-level mono recorder of the era, focused on clear voice and light music)

• Signal-to-Noise Ratio: 45–50 dB (typical; modest but adequate for non-professional use)

• Wow & Flutter: ≈0.2% (at 3¾ ips; 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 (2.2 mV; dynamic mic via DIN or proprietary socket; often supplied external mic)
  Line/Radio: High-level (500 mV / 27 kΩ; 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, typically 7¼ × 4 inches or 182 × 97 mm); line out via DIN socket (0.5 V); output power ≈2.5–4 watts

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

• Dimensions: Approximately 400 × 180 × 290 mm / 15.75 × 7.1 × 11.4 inches (W × H × D) — compact suitcase/portable form factor with handle

• Weight: Approximately 8.5 kg / 18.7 lbs — portable yet substantial due to metal chassis and components

• Electronics: Hybrid valve/tube + transistor-based (typically 5 tubes + transistors/semiconductors): EF86 preamp, EF83 stage, ECL86 output (combined triode-pentode), ECC81 phase splitter/driver, EM87 magic eye level indicator; semiconductors (E20C3, E45C5, B250C100, B30C600 rectifiers) for power supply and some stages

• Other Features: Magic eye (EM87) recording level indicator (glow for level monitoring); mechanical tape counter; automatic tape-end stop; pause function; recording time ≈2 hours total (1 hour per direction, longer with LP tape and track usage) on 6–7-inch reels

Design and Performance Notes

The TK 145 was a straightforward, budget-oriented domestic recorder with a focus on simplicity and reliability: push-button controls and the hybrid circuitry delivered a clean, intelligible tone suitable for voice, radio dubbing, or casual music playback/recording, with basic fidelity for its class—modern vintage ratings place it around 5–6/10 for sound (functional mono performer, not audiophile-grade) and 6–7/10 for build reliability/durability (robust but basic).

The drive mechanism was simple and durable, with minimal electronics complexity. The de Luxe/Automatic versions often included cosmetic upgrades (better cabinet finish) or minor electronic refinements (e.g., improved level indication or AVC circuitry). Common long-term service needs include:

• Tube replacement/check (EF86 microphonics; ECL86 output wear)

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

• Replacing electrolytic capacitors (leakage common after 50+ years)

• Replacing rubber drive belts/idlers (common failure point in 1960s models)

• Lubricating mechanisms

• Magic eye alignment and rectifier checks

Historical Context

The TK 145 was part of Grundig's extended 1960s TK series that transitioned toward more accessible consumer models with hybrid electronics. It followed budget mono machines like the TK 120/TK 125/TK 140 and preceded later multi-speed/stereo machines (TK 14x, TK 24x, etc.). Surviving examples are collectible today as entry-level vintage pieces, often in good cosmetic condition due to sturdy construction, but most require basic restoration (especially rubber drive components, tubes, and capacitors) for reliable operation. They represent an accessible entry into vintage tube-era open-reel collecting, especially for those interested in late-1960s German budget audio engineering and quarter-track mono designs with automatic features.