Philips N4307

The Philips N4307 (also marketed as Maestro 4307 in some regions, with variants like N4307/00, /55, etc.) is a late 1960s to early 1970s consumer reel-to-reel tape recorder, produced approximately 1968–1972/1973. It belongs to Philips' early solid-state N43xx series, positioned as an affordable, reliable entry-to-mid-level mono tape recorder for home use—radio off-air recording, voice, family events, dictation, and light music dubbing.

This model was fully transistorized (no vacuum tubes), featured a built-in speaker for self-contained operation, and used quarter-track (4-track) heads to allow recording in both directions of the tape, effectively doubling playing time per reel.

Key Technical Specifications

• Recording/Playback System — 4-track (quarter-track) mono recording; playback mono (stereo tapes playable in mono or summed via external amp); records on tracks 1-4 forward, 3-2 reverse (manual tape flip required for second pair); basic multiplay/overdub capability in limited form.

• Tape Speeds — Single speed: 3¾ ips (9.5 cm/s). (No 1⅞ ips or 7½ ips; focused on a good balance of recording time and sound quality.)

• Reel Size — Up to 7 inches (18 cm) maximum diameter (standard consumer reels, including long-play tapes).

• Frequency Response (approximate, within typical tolerances of ±3–6 dB):At 3¾ ips: 60 Hz – 14,000 Hz (some sources list 80–14,000 Hz; realistic upper limit around 10–12 kHz with good tape).
  

• Wow & Flutter — 0.25% (DIN weighted) or ±0.25% (very respectable for a single-motor consumer machine of the era).

• Signal-to-Noise Ratio — >45 dB (or ≈45 dB; good performance thanks to full transistor design).

• Heads — 2 heads: combined record/playback (permalloy) + erase head.

• Drive System — Single asynchronous motor; belt drive to capstan/flywheel; idler tires and clutches for take-up/supply; mechanical brakes; fast wind/rewind (≈1200 ft in 180 seconds).

• Electronics — Fully transistorized (typically 9–10 transistors, including BC107/BC108/BC109 series and output pairs like AC187/AD161); printed circuit board amplifier.

• Amplification & Speakers — Built-in mono amplifier; internal permanent magnet dynamic loudspeaker (typically oval ≈150 × 100 mm or similar); output power ≈2.5–4 W sine wave; basic tone control.

• Inputs —Microphone (low-level, ≈0.2 mV).
  Radio/line/phono (higher level, ≈150–200 mV).
  DIN-style connectors standard.
  

• Outputs —Line out (≈1 V).
  Internal speaker.
  External speaker (≈4 W / 4–8 ohms).
  DIN-style.
  

• Features —Track/direction selector.
  Manual recording level control.
  Basic mixer (parallel connection of sources).
  Fast wind/rewind, pause.
  Portable/tabletop design with lid and carry handle.
  No auto-reverse or advanced editing functions.
  

• Power — AC mains (110/127/220/245 V switchable, multi-voltage export models); consumption ≈40 W.

• Build & Dimensions — Tabletop case (often grey/charcoal plastic with wood accents); approx. 420 × 140 × 300 mm (16.5 × 5.5 × 11.8 inches); weight ≈7.5 kg (≈16.5 lb).

• Manufacturing — Primarily Austria (Philips Österreich) or Netherlands (Eindhoven facilities); some regional variants.

Performance & Legacy Context

The N4307 was a very popular, no-frills consumer deck in the late 1960s/early 1970s—quiet, reliable, and surprisingly good-sounding at 3¾ ips for its price class. It offered decent clarity for voice, radio broadcasts, and light music, and performed well when connected to an external hi-fi amplifier. The single speed and mono design kept it simple and affordable compared to stereo models like the N4407/N4408 (which added 7½ ips and true stereo recording).

Common issues today include:

• Belts turning into sticky goo (main drive belt + idler/counter belts—replacement kits widely available).

• Dried electrolytic capacitors.

• Transistor aging (especially output stage).

• Dirty heads, worn idler tires/clutches.

• Mechanical lubrication points and brake adjustments needing attention.

Restorations are common and usually successful; many detailed YouTube refurbishment videos exist for the N4307. Service and user manuals are readily available (e.g., 1969 service manual with schematics on Elektrotanya, Internet Archive, HiFi Engine, or Retronik).

Compared to close siblings:

• N4308 — Extremely similar (sometimes considered the same machine with minor regional differences).

• N4407 — Stereo version with three speeds including 7½ ips.

• N4038/N4308 variants — Minor suffix differences for voltage or market.