Grundig TK 147

The Grundig TK 147 (also known as TK147 HiFi or TK 147 de Luxe in some markets) is a solid-state open-reel (reel-to-reel) tape recorder produced by Grundig Radio-Vertrieb in Fürth, Germany. Manufactured primarily from 1970 to 1974, it was a mid-range quarter-track stereo recorder aimed at home users and enthusiasts seeking affordable stereo capability with decent performance for its class. It was essentially the stereo version of the mono TK 146, sharing the same chassis and most internals but upgraded with stereo heads and electronics.

The TK 147 was priced originally around 450–500 DM (a mid-range consumer figure, equivalent to roughly £50–60 in export markets), positioning it as an accessible entry into stereo open-reel recording. It was valued for its push-button operation, automatic recording level control (in some variants), and solid build quality, though it was not a top-tier audiophile machine.

Key Technical Specifications

Track System: 4-track (quarter-track), 2-channel stereo / monaural (stereo record/playback; monaural operation also supported; records on one quarter-track per pass, allowing four tracks total on standard tape by flipping reels twice; some sources note half-track playback compatibility)

• 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 5.75 inches / 146 mm (often listed as up to 5¾–7 inches in practice; commonly used with 5–5.75 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 stereo design requires careful alignment for track compatibility)

• Motors: 1 motor (capstan drive; single-motor design 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; constant tape speed; foil-sensing automatic stop at tape end; basic tension regulation suitable for standard tape

• Frequency Response: 40 Hz – 12.5 kHz (±3 to –5 dB at 3¾ ips; respectable for a single-speed entry-level stereo recorder of the era, focused on clear voice and light music)

• Signal-to-Noise Ratio: ≈48–50 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 (~1 mV / 100 kΩ; dynamic mic via DIN or proprietary socket; often supplied external mic)
  Line/Radio: High-level (~100 mV; via DIN connector; Grundig 5-pin standard)
  Phono/Grammophon: Additional high-level input for record players
  

• Outputs: Built-in loudspeaker (internal elliptical permanent-magnet dynamic type, typically 7¼ × 3¾ inches); line out via DIN socket (500 mV / 27 kΩ stereo preamp output for external amplifiers); output power 4 watts (mono only – external amp & speakers required for stereo)

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

• Dimensions: Approximately 393 × 292 × 159 mm / 15.5 × 11.5 × 6.25 inches (W × H × D) — compact suitcase/portable form factor with handle

• Weight: Approximately 8 kg / 17.6 lbs — portable yet substantial due to metal chassis and components

• Electronics: Fully solid-state (transistor-based; 18 transistors + 10 diodes; no tubes, marking the shift to transistorization in Grundig's budget/mid-range line)

• Other Features: Recording level indicator (VU meter or glow type); 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 5.75-inch reels

Design and Performance Notes

The TK 147 was a straightforward, budget-oriented stereo recorder with a focus on simplicity and reliability: push-button controls and the solid-state circuitry delivered a clean, intelligible stereo 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 stereo 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. Stereo playback required external amplifiers and speakers (internal speaker mono only). Common long-term service needs include:

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

• Replacing rubber drive belts/idlers (common failure point in 1970s solid-state models)

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

• Lubricating mechanisms

• Checking transistor stages and power supply

Historical Context

The TK 147 was part of Grundig's extended 1960s–1970s TK series that transitioned toward more accessible consumer models with solid-state electronics and stereo capability. It followed budget mono machines like the TK 146 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 and capacitors) for reliable operation. They represent an accessible entry into vintage solid-state open-reel collecting, especially for those interested in early-1970s German budget audio engineering and early quarter-track stereo designs.