Grundig TK 35

The Grundig TK 35 (also known as TK35 or TK 35 in various markets, sometimes labeled TK 35 de Luxe or TK 35 L in upgraded variants) is a late-1950s open-reel (reel-to-reel) tape recorder produced by Grundig Radio-Vertrieb in Fürth, Germany. Manufactured primarily from 1958 to around 1962–1963, it was a mid-to-high-end mono domestic/portable machine aimed at serious home users, radio enthusiasts, and semi-professional hobbyists. It was one of Grundig's flagship mono models of the era, offering three tape speeds, large reel capacity, excellent audio performance, and a refined "Luxus" build quality.

The TK 35 was priced originally around £70–90 in export markets (equivalent to roughly 700–900 DM in Germany), positioning it as a premium consumer recorder. It gained a strong reputation for its superior frequency response, dynamic range, low noise, and versatility, making it highly regarded among vintage collectors today as one of the best mono Grundig recorders of the 1950s.

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: 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 was a major selling point, offering high-fidelity music recording at 7½ ips and extended runtime at slower speeds)

• Reel Size: Maximum 7 inches / 18 cm (standard for high-end domestic recorders of the era; supports 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; high-quality split-phase induction motor typical of late-1950s premium consumer machines)

• Drive System: Mechanical transport with push-button or lever controls; constant tape speed; foil-sensing automatic stop at tape end; basic tension regulation suitable for standard and thinner tapes; sound-on-sound (erase cut-out) for overdubbing in some configurations

• Frequency Response:50 Hz – 18 kHz (±3 dB) at 7½ ips
  50 Hz – 12 kHz at 3¾ ips
  50 Hz – 8 kHz at 1⅞ ips (excellent for the era, especially at 7½ ips; one of the widest responses in Grundig's mono lineup)
  

• Signal-to-Noise Ratio: Better than 50 dB (weighted; very good for mid-century consumer mono, aided by quality tube design and low-noise circuitry)

• Wow & Flutter: Less than 0.15% at 7½ ips; less than 0.2% at 3¾ ips; less than 0.25% at 1⅞ ips (outstanding for domestic use; among the lowest figures in Grundig's 1950s 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)
  Diode (auxiliary): 1.5 mV / 22 kΩ
  Radio/Line: 100 mV / 1 MΩ via DIN connector (Grundig 5-pin standard)
  Phono/Grammophon: Additional high-level input for record players
  

• Outputs: Built-in loudspeaker (high-flux elliptical permanent-magnet dynamic type, typically 5¾” × 8¼”); low-impedance ext. speaker (3 ohms); high-impedance line out (600 mV / 5 kΩ) via DIN socket; output power 3½–4 watts

• Power Supply: Alternating Current (AC) mains — 110–240 V (multi-voltage taps for export); power consumption around 60–80 W; no battery option (mains-only domestic/portable hybrid)

• Dimensions: Approximately 457 × 457 × 292 mm / 18 × 18 × 11½ inches (W × H × D) — larger suitcase/portable form factor with handle (larger than TK 20–TK 25 series due to bigger chassis and speakers)

• Weight: Approximately 15–16 kg (33–35 lbs) — substantial due to metal chassis, multiple speakers, transformers, and tubes

• Electronics: Valve/tube-based (typically 5–6 tubes): EF86 preamp, ECC81 phase splitter/driver, EL84 (or EL95) output (push-pull), EM84 magic eye level indicator; 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; sound-on-sound (erase cut-out) for overdubbing; rewind speed ≈2½ minutes for full 7-inch reel; recording time up to 4–6 hours total (depending on speed, tape thickness, and track usage) on 7-inch reels with long-play tape

Design and Performance Notes

The TK 35 was a high point in Grundig's mono tube-era lineup: triple speeds provided exceptional versatility—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 and extension compared to earlier models like the TK 20–TK 25—modern vintage ratings place it around 8/10 for sound (one of the finest mono Grundig recorders of the 1950s) and 8–9/10 for build reliability/durability.

The drive mechanism was robust and precise, with minimal electronics complexity. Common long-term service needs include:

• Tube replacement/check (EF86 microphonics; EL84/EL95 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 35 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 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 late-1950s/early-1960s German audio engineering and high-performance mono triple-speed designs.