Aristona 9137

The Aristona 9137 is a consumer-grade 4-track stereo/mono reel-to-reel tape recorder from around 1969, produced under the Aristona brand (a budget/export sub-brand of Philips, Netherlands). It is mechanically and electronically identical to the Philips N4407 (also known as Maestro 4407 in some markets). Other possible rebadges include certain Pye or DUX variants.

Key Technical Specifications

• Format: Open-reel (reel-to-reel) magnetic tape recorder.

• Track Configuration: 4-track (quarter-track). Supports stereo recording and playback, as well as mono operation. It can play pre-recorded stereo tapes and record in stereo using two microphones or line sources.

• Tape Speeds: Three speeds — 4.75 cm/s (1⅞ ips), 9.5 cm/s (3¾ ips), and 19 cm/s (7½ ips). The highest speed provides the best audio quality for music.

• Reel Capacity: Maximum 18 cm (7 inches) diameter reels.

• Drive System: Single-motor capstan drive with pinch roller. This design was common and cost-effective for mid-level consumer machines of the late 1960s.

• Heads: Typically two heads (erase + combined record/play head).

• Electronics: Fully solid-state (all-transistor design, approximately 20 transistors). No vacuum tubes.

• Amplification: Built-in stereo power amplifier with roughly 4 watts output per channel (or total, depending on exact measurement) for direct connection to speakers or monitoring.

• Inputs: Microphone (low-level, ~0.2 mV), line/phono/radio (~100 mV).

• Outputs: Line out (~1 V), headphone jack, external speaker outputs. Built-in monitoring via the amplifier.

• Power Supply: AC mains, switchable 110–240 V, 50/60 Hz. Power consumption around 29 W typical.

• Dimensions (approx.): 480 mm × 340 mm × 190 mm (width × depth × height).

• Weight: Not precisely documented but typical for a sturdy tabletop Philips-era unit (around 8–10 kg).

Features

• Stereo recording/playback with 4-track format (longer recording time per reel compared to half-track).

• Mixing capability for mic + line sources in some operating modes.

• Basic transport controls: Record, Play, Pause, Stop, Fast Forward, Rewind.

• Recording level controls and indicators (VU-style or magic eye in related models).

• Counter for tape position (belt-driven; rubber parts often degrade over time).

• Designed for home use: recording live music, dubbing from radio/vinyl, voice, or family archives.

Performance Context

As a late-1960s consumer machine, the Aristona 9137 / Philips N4407 offered good performance for its class and price. At 19 cm/s, frequency response reaches into the upper mid-range suitable for music (typically 40–15,000 Hz or better, though exact curves vary by condition). Wow & flutter is reasonable at higher speeds (e.g., ~0.07% at 9.5 cm/s, higher at 4.75 cm/s). Signal-to-noise ratio is adequate but not studio-grade. The single-motor drive provides acceptable stability for non-professional use.

It sits above the simpler dual-speed Aristona 9121/9123 models you asked about earlier, thanks to the added third (high) speed and full stereo recording capability.

Build and Market Position

• Tabletop design with typical Philips functional styling of the era (metal chassis, plastic elements).

• Robust for home/entertainment use but not a professional or hi-fi audiophile deck (compare to Revox or higher-end Philips models).

• Popular in Europe as an affordable stereo tape recorder for enthusiasts and students.

Common Restoration Issues

Surviving units often need:

• Replacement of hardened rubber parts (pinch roller, drive belts/idlers, and counter belt — belt sets are still available).

• Spool holder "wings" (the plastic fins that secure reels) frequently break with age; donors from other N4407 units are commonly used.

• Aged electrolytic capacitors in the audio and power sections.

• Thorough cleaning/lubrication of the tape path, head cleaning, demagnetization, and azimuth alignment.

• Speed calibration check, especially at the three different speeds.

Service manuals and parts (including belt kits) are available under the Philips N4407 designation.