Philips EL3552

The Philips EL3552 (including variants like EL3552/00, /15, EL3552A, or rebranded as Norelco Continental '95' or RK12 in some markets) is a budget-oriented mid-1960s consumer reel-to-reel tape recorder, produced roughly 1965–1967. It was part of Philips' EL35xx series, aimed at entry-level home users for voice, radio off-air recording, and basic music dubbing. This model stands out as a hybrid design: mostly tube (valve)-based amplification with a single transistor in the first preamp stage to minimize hum and noise—a clever cost-saving compromise before fully transistorized models became standard.

It was a simple, reliable half-track (two-track) mono recorder with a single speed, emphasizing affordability, ease of use, and compact size over advanced features like multiple speeds or stereo.

Key Technical Specifications

• Recording/Playback System — Half-track (two-track) mono; records and plays in one direction only (no reverse playback without flipping the tape); basic mono recording on track 1, playback from track 1 or 2 if pre-recorded.

• Tape Speeds — Single speed: 3¾ ips (9.5 cm/s). (No multi-speed capability; optimized for a balance of recording time and quality on consumer tapes.)

• Reel Size — Maximum 5¾ inches (≈14.6–15 cm) diameter (some sources note up to 5" or 13 cm spools comfortably; smaller than the 7" reels on higher models like EL3549).

• Frequency Response (approximate, typical for budget consumer tube decks of the era; within ±3–6 dB):At 3¾ ips: ~60–10,000 Hz (some claims up to 12,000 Hz, but realistic upper limit ~8–10 kHz with good tape). Adequate for speech and light music, but limited highs compared to 7½ ips decks.
  

• Wow & Flutter — Around 0.3–0.5% (acceptable for entry-level; single-motor belt/idler drive keeps it simple and stable enough for casual use).

• Signal-to-Noise Ratio — Approximately 40–45 dB (benefited slightly from the transistor input stage reducing front-end noise/hum).

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

• Drive System — Single asynchronous motor; belt drive to capstan/flywheel; simple flat-plate mechanics with idler/pulley for tape transport; mechanical brakes; very basic and reliable design.

• Electronics — Hybrid: 4 vacuum tubes (typically EF83, ECC83, EL95 output, EM87 magic eye level indicator) + 1 transistor (e.g., AC107 in the first preamp stage for low-noise input); printed circuit board amplifier; no complex equalization circuits.

• Amplification & Speakers — Built-in mono amplifier; internal permanent magnet dynamic loudspeaker (~1.5 W output); basic tone control (if present); low-power but sufficient for monitoring.

• Inputs —Microphone: ~2.5 mV / 3 kΩ (moving-coil type supplied).
  Radio/line/phono: higher level (adapter like NG-1201 for record player).
  Likely DIN-style connectors.
  

• Outputs — Internal speaker; line out (~0.75 V); possible extra speaker or headphone.

• Features —Push-button or lever transport controls (record, play, rewind, fast forward, stop).
  Magic eye (EM87) recording level indicator.
  Manual/auto recording modes.
  Pause function (limited).
  Supplied accessories often included microphone, 5" LP tape reel, empty spool, connecting leads.
  

• Power — AC mains (110/127/220/240 V switchable, 50/60 Hz); consumption low (~30–50 W).

• Build & Dimensions — Compact tabletop/portable case with lid and carry handle; approx. 360 × 125 × 255 mm (14.2 × 4.9 × 10 inches) or similar; weight ~6–8 kg (light for the era due to simplicity).

• Manufacturing — Primarily Netherlands (Eindhoven) or licensed facilities (e.g., Philips Ibérica, Deutsche Philips); some regional variants.

Performance & Legacy Context

The EL3552 was a true entry-level "people's recorder"—inexpensive (often sold for the equivalent of ~£24–30 in the mid-1960s), straightforward, and surprisingly robust thanks to its minimalist mechanics. It excelled for dictation, family recordings, or radio capture at 3¾ ips, with decent clarity for its price class. The single transistor in the preamp gave it a slight edge in noise over pure-tube contemporaries, while retaining the characteristic tube warmth in the output.

Compared to nearby series siblings:

• EL3549 (1963): Fully transistorized, four speeds (including 7½ ips), 7" reels, more versatile.

• EL3548 (mid-1960s): Hybrid similar but different config, 2 speeds, 7" reels.

• EL3552 focused on ultimate simplicity and low cost, sacrificing speed options and reel size.

Common issues today: hardened belts/idler tires (slipping causes wow/flutter), dried electrolytic capacitors, tube aging (especially EL95 output and EM87 eye), dirty heads, and oxidized switches. Restorations are straightforward—belts, recap, and tube checks often restore full function. Service manuals are available (e.g., via HiFi Engine, Retronik, Elektrotanya, or KevinChant.com PDFs), including schematics and alignment procedures.