Aiwa CS-120
At 8.4 kg, it’s not coming with you casually—but when it’s on, the room belongs to it.
Overview
The Aiwa CS-120 is a stereo radio cassette recorder from Aiwa Co. Ltd., firmly planted in the company’s CS-series boombox lineage. This is no pocket machine—its 490 mm width and 8.4 kg mass signal serious intent. It was built to dominate a dorm room, a backyard, or a garage, delivering 12 watts of EIAJ-rated power through a dual 16 cm woofer and dual 5 cm tweeter setup. It was priced at ¥79,800 around 1980, placing it in the upper tier of portable audio gear at the time. Despite its weight, it supports three power modes: AC, 8 AAA batteries (12 VDC), or car battery via adapter, with approximately 8 hours of playback expected on dry cells.
It’s a machine of layers: radio, recording, mixing, and playback, all governed by a dense front panel of LEDs and controls. The CS-120 supports C-30 through C-120 tapes, uses AC bias and erase, and features a 4-track 2-channel stereo system. Its frequency response stretches to 15 kHz on CrO2 tapes, and with a wow and flutter of just 0.07% WRMS, it’s engineered for fidelity within the portable format’s limits. The signal-to-noise ratio of 54 dB (JIS, line out) suggests a clean signal path, though not class-leading for its era.
Two built-in condenser microphones allow live voice mixing during playback, with independent volume control—a feature aimed at aspiring DJs or party hosts. “One touch recording” is supported, and users can toggle between Mono, Stereo, and Wide-Stereo playback modes. The analogue tuner covers FM (76–90 MHz), SW (3.9–12 MHz), and MW (525 kHz–1,605 kHz), with a whip antenna for FM/SW and a ferrite bar for MW, plus an external FM antenna terminal. An AFC switch and FM muting mechanism help stabilize reception.
Specifications
| Manufacturer | Aiwa Co. Ltd. |
| Product type | Stereo Radio Cassette Recorder (boombox) |
| Original price | ¥ 79,800 (around 1980) |
| Receiving frequency | FM : 76 MHz to 90 MHz; SW : 3.9 MHz to 12 MHz; MW : 525 kHz to 1,605 kHz |
| Antenna | FM, SW : Whip antenna; MW : ferrite bar antenna; Equipped with FM external antenna terminal |
| Track system | 4-track 2-channel stereo system |
| Recording system | AC bias |
| Erasing method | AC erase |
| Tape used | C-30, C-60, C-90 (C-120) |
| Recording time | 60 minutes (C-60 round trip) |
| Frequency characteristic | 40 Hz ~ 12.5 kHz (Normal Tape); 40 Hz ~ 15 kHz (CrO2 Tape) |
| Signal-to-noise ratio | 54dB(Line out(JIS)) |
| Wow flutter | 0.07%(WRMS) |
| Microphone | 2 built-in condenser microphones |
| Maximum practical power | Total 12W (6.0W + 6.0W, EIAJ/DC) |
| Input terminal | Mic Jack : 3.5 φ Mini Type x2; Line in jack : 2 pin types |
| Output terminal | Line out jack : 2 pin types; EXT. SP Jack : 3.5 φ Mini Type x2; Phones jack : 6.3 φ standard jack |
| Speakers | For low band : 16 cm cone x2; For high pass : 2 x 5.0 cm cone type |
| Semiconductor used | IC : 12; Transistor : 41; Diode : 19 units; LED : 10 pcs; FET : 1 |
| Power | AC Power : 100 VAC, 50Hz/60Hz; Battery Power Supply : 12 VDC (8 AAA batteries); Car battery (combined with car adapter) |
| Power consumption | 20W (at AC) |
| Battery life time | Approximately 8 hours (when using EIAJ and SUM-1 dry battery) |
| External dimensions | Width 490x Height 273x Depth 165 mm |
| Weight | 8.4 kg (including battery) |
| Attachment | AC power cord; Erase Plug x1 |
Key Features
2-Way Speaker System with 16 cm Woofers and 5 cm Tweeters
The CS-120 uses a dedicated 2-way speaker configuration, pairing two 16 cm cone woofers for low-band reproduction with two 5 cm cone tweeters for high-pass duties. The speaker units include aluminum caps, likely for heat dissipation or structural rigidity. This setup, combined with the BTL (ITL/OTL) amplifier circuit, contributes to its 12W output. While not massive by home receiver standards, this is substantial for a portable unit of its era. The dual external speaker jacks (3.5 φ Mini Type x2) allow expansion, though impedance matching is not specified.
Sendust SG Record/Playback and SE Erase Heads
Aiwa equipped the CS-120 with Sendust guard (SG) for the record/playback head and Sendust double-gap (SE) for the erase head. Sendust is a magnetic alloy known for durability and consistent performance, often used as a mid-tier alternative to permalloy or ferrite. The double-gap erase head improves erasure efficiency, particularly important when switching between tape types. These choices suggest a focus on reliability and tape compatibility across Normal, CrO2, Metal, and LH tapes.
One-Lever Tape Selector for Bias and Equalizer Switching
Switching between tape types—Normal, CrO2, Metal, LH—is handled via a single lever that adjusts both bias and equalization. This simplifies operation and reduces user error, a thoughtful design in an era when mis-set bias could ruin a tape. The system supports CrO2 tapes with a frequency response up to 15 kHz, indicating proper 70 µs equalization. No data is available on metal tape performance beyond compatibility.
Double Capstan System with 180° Rotating Head and Infrared Sensor
The transport uses a double capstan system for stable tape speed control, paired with a 180° rotating record/playback head—essential for bidirectional playback without flipping the tape. An infrared tape sensor enables quick reverse operation, allowing near-instant direction changes. This mechanism, combined with the quick reverse function that supports metal tapes, positions the CS-120 as a machine built for active use, not just passive listening.
Music Sensor with 9-Point LED Display
A music sensor function detects up to nine songs, indicated by a 9-point LED display. This was a premium feature at the time, allowing users to navigate tape content without manual counting. Combined with queue and review functions, full auto-stop, and mechanical pause, it reflects Aiwa’s push toward intelligent tape management in a portable form.
ALC with Independent Left/Right Recording Level Knobs
The CS-120 includes ALC (automatic level control) for recording, but also provides manual override via independent left and right recording level knobs. This hybrid approach gives users both convenience and control—ideal for field recording or dubbing from external sources. The two mic inputs (3.5 φ mini jacks) support mono microphone input, and the playback mixing mechanism allows real-time voice-over with adjustable mic volume.
Analogue Tuner with 3-Gang Variable Capacitor and Ceramic IF Filter
The FM tuner employs a 3-gang variable capacitor and FETs in the front end, with a 2-element ceramic filter in the IF stage and a PLL-IC in the MPX circuit. This combination suggests a well-engineered RF section, aiming for selectivity and stability. The inclusion of an AFC switch and FM muting mechanism further supports clean reception, especially in fringe areas.
Integrated Phono Equalizer and Line I/O
A built-in phono equalizer circuit allows direct connection of a turntable, eliminating the need for an external preamp. Line-in and line-out jacks (2-pin types) enable daisy-chaining with other audio gear or recording from external sources. The presence of both inputs and outputs makes the CS-120 a potential hub in a small audio setup, despite its portability.
Timer Standby and Alarm Playback
The unit includes a timer standby mechanism, enabling absence recording and alarm playback. This positions it as a multi-role device—part boombox, part clock radio, part field recorder. Combined with the three power options, it could function as a standalone audio station in various environments.
Collectibility & Value
A used Aiwa CS-120 was listed for sale on eBay.at for EUR 25.00, suggesting low current market demand. No average resale value or auction history is documented for this specific model. A service manual is available for download from third-party electronics sites, which may aid repair but does not indicate common failure points. The Aiwa CSD-A120, a different model, has an average market price of $110.62 according to PicClick, but this should not be conflated with the CS-120’s value.
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