Philips N7150

The Philips N7150 (including variants like N7150/00 or sometimes labeled N7150 A) is a late 1970s to early 1980s consumer stereo reel-to-reel tape recorder, produced approximately 1980–1983 (one of Philips' last open-reel models before the format was phased out in favor of cassettes). It was positioned as a mid-range hi-fi stereo deck for home use, with a focus on decent sound quality, three speeds, and a three-head configuration for off-tape monitoring. The N7150 is often described as Philips' final reel-to-reel effort in the consumer market—reliable when new but now notorious among restorers for its extensive use of plastic components (chassis, gears, platters, idlers), which leads to common wear and gooey degradation over time.

This was a 4-track (quarter-track) stereo recorder with true stereo recording and playback in both directions, built-in stereo amplification, and dual internal speakers for self-contained operation. It targeted home music recording, radio dubbing, and hi-fi playback during the tail end of the open-reel era.

Key Technical Specifications

• Recording/Playback System — 4-track (quarter-track), 2-channel stereo/mono compatible; records and plays stereo on tracks 1-4 forward and 3-2 reverse (manual tape flip required for second pair); mono compatible; sound-on-sound/multiplay overdub facilities; no auto-reverse.

• Tape Speeds — Three speeds:1⅞ ips (4.75 cm/s)
  3¾ ips (9.5 cm/s)
  7½ ips (19 cm/s)
  

• Reel Size — Up to 7 inches (18 cm) maximum diameter (coil diameter 13–18 cm; tape lengths 270, 360, 720 m; thickness 25–55 µm).

• Frequency Response (approximate, typical tolerances; varies by tape/condition):At 7½ ips: 40 Hz – 18,000 Hz (or up to 20,000 Hz in optimal conditions)
  At 3¾ ips: 40 Hz – 15,000 Hz
  At 1⅞ ips: ~60 Hz – 10,000 Hz Respectable hi-fi performance at higher speeds for a late consumer deck.
  

• Wow & Flutter — Approximately 0.15–0.3% at 7½ ips (higher than premium models due to DC motor and plastic components; prone to worsening with wear).

• Signal-to-Noise Ratio — 48 dB (DIN weighted; typical for mid-range transistor design).

• Heads — 3 heads: 1 × playback, 1 × record, 1 × erase (permalloy; allows off-tape monitoring).

• Drive System — Three motors (2 × reel DC motors + 1 × capstan DC motor; plus 1 × mechanism motor in some descriptions); belt/idler drive (heavy reliance on plastic gears, idlers, and indentations for platter drive—not direct drive); electronic or mechanical tension; fast wind/rewind; mechanical brakes.

• Electronics — Fully transistorized; printed circuit board amplifier.

• Amplification & Speakers — Built-in stereo amplifiers; dual internal loudspeakers; output power sufficient for monitoring (typically ~few watts per channel; some versions allow external speaker drive).

• Inputs —Microphone: 0.3 mV
  Line/DIN: 2 mV
  Line (alternative): 50 mV
  DIN-style connectors standard.
  

• Outputs —Line out: 1 V
  Headphones (monitor).
  External speakers or amp.
  DIN-style.
  

• Features —Twin VU meters (needle type; active for record/playback).
  Push-button transport controls (mechanical).
  Input mixing.
  Tape counter.
  Off-tape monitoring (source/tape).
  Pause function.
  Portable/tabletop design with lid/handle; vertical/horizontal orientation.
  

• Power — AC mains (multi-voltage switchable); consumption moderate.

• Build & Dimensions — Tabletop case (often plastic-heavy chassis with wood accents); approx. ~500 × 400 × 200 mm (estimated from similar series); weight ~10–12 kg.

• Manufacturing — Primarily Austria (Philips Österreich); one of the last Philips reel-to-reel models.

Performance & Legacy Context

The N7150 was a competent late-era consumer deck—offering three-head monitoring, three speeds (including usable 7½ ips for music), and integrated stereo amp/speakers for convenience. It delivered decent clarity and stereo imaging at 7½ ips when new/serviced, with good dynamics for home hi-fi. However, it is now infamous in restoration communities for poor long-term durability: extensive plastic construction (gears, platters with plastic indentations, idlers), small DC motors (limited torque, fast wear, poor wow/flutter over time), and belt/idler degradation (goo/melting common). Many units suffer speed instability, shaking arms, or mechanical failure after decades.

Compared to siblings:

• N4520/N4522 — Later flagship with quartz PLL, glass-ferrite heads, 15 ips, and 10.5" reels—far superior.

• N4510/N4512 — Close predecessors (three motors/heads but less advanced).

• N7150 — Late, budget-oriented in Philips' final open-reel phase (plastic-heavy, DC motors).

Common issues today: Plastic gear/idler wear (replacements via 3D print or kits), belt goo, dried electrolytic capacitors, transistor aging, dirty heads (3-head alignment critical), motor wear (DC types prone to failure), and transport mechanics. Restorations are possible but labor-intensive—many collectors consider it a "parts donor" or entry-level project rather than a keeper. Service/user manuals available (HiFi Engine, Elektrotanya—schematics and alignment).