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., part of the company's CS-series boombox line. It is not a pocket machine. It is 490 mm wide and weighs 8.4 kg. It was built for a dorm room, a backyard or a garage, and it puts out 12 watts EIAJ through dual 16 cm woofers and dual 5 cm tweeters. The price was ¥79,800 around 1980, which put it in the upper tier of portable audio gear at the time. Despite the weight, it runs three ways: AC, 8 AAA batteries (12 VDC), or a car battery through an adapter. Expect approximately 8 hours of playback on dry cells.

It does radio, recording, mixing and playback, all run from a dense front panel of LEDs and controls. The CS-120 takes C-30 through C-120 tapes, uses AC bias and erase, and has a 4-track 2-channel stereo system. Frequency response reaches 15 kHz on CrO2 tapes, and wow and flutter is just 0.07% WRMS. The signal-to-noise ratio is 54 dB (JIS, line out). That suggests a clean signal path, though not class-leading for its era.

Two built-in condenser microphones let you mix live voice over playback, with independent volume control. It was aimed at aspiring DJs and party hosts. "One touch recording" is supported, and playback can be switched between Mono, Stereo and Wide-Stereo. The analogue tuner covers FM (76-90 MHz), SW (3.9-12 MHz) and MW (525 kHz - 1,605 kHz). There is a whip antenna for FM/SW, a ferrite bar for MW, and 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 setup: two 16 cm cone woofers for the low band and two 5 cm cone tweeters for high-pass duties. The speaker units have aluminum caps, likely for heat dissipation or structural rigidity. Together with the BTL (ITL/OTL) amplifier circuit, this gives the 12W output. That is not massive by home receiver standards, but it is substantial for a portable 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 fitted the CS-120 with a Sendust guard (SG) record/playback head and a Sendust double-gap (SE) 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, which matters most 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

Tape type - Normal, CrO2, Metal or LH - is selected with a single lever that adjusts both bias and equalization. That simplifies operation and cuts down on user error, which counted for something when mis-set bias could ruin a tape. The CrO2 response up to 15 kHz indicates 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, paired with a 180° rotating record/playback head for bidirectional playback without flipping the tape. An infrared tape sensor enables quick reverse operation, with near-instant direction changes. The quick reverse function also supports metal tapes.

Music Sensor with 9-Point LED Display

A music sensor detects up to nine songs, shown on a 9-point LED display. This was a premium feature at the time, and it saved users from counting by hand. It is joined by queue and review functions, full auto-stop and mechanical pause.

ALC with Independent Left/Right Recording Level Knobs

The CS-120 has ALC (automatic level control) for recording, plus manual override through independent left and right recording level knobs. That gives both convenience and control for field recording or dubbing from external sources. The two mic inputs (3.5 φ mini jacks) take 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 has a 3-gang variable capacitor and FETs in the front end, a 2-element ceramic filter in the IF stage, and a PLL-IC in the MPX circuit. That suggests a well-engineered RF section aimed at selectivity and stability. The AFC switch and FM muting mechanism further support clean reception, especially in fringe areas.

Integrated Phono Equalizer and Line I/O

A built-in phono equalizer circuit allows a turntable to connect directly, with no external preamp. Line-in and line-out jacks (2-pin types) allow daisy-chaining with other audio gear or recording from external sources. With both inputs and outputs, the CS-120 could act as a hub in a small audio setup despite being portable.

Timer Standby and Alarm Playback

The unit has a timer standby mechanism for absence recording and alarm playback. That makes it part boombox, part clock radio, part field recorder. With the three power options, it could work 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.