Toshiba KT-S1

The KT-S1 is a stereo cassette player manufactured by the Toshiba Corporation in Japan. During its introduction in 1981, it would have been a high-end player in the style of a Walkman. It is extremely well built with a robust metal chassis and cassette compartment. One interesting feature is that it comes with a tuner module (in the shape of a cassette) that fits into the cassette compartment to provide radio functions.

In 1981, audio chip technology had advanced sufficiently enough to manufacture a mono tape recorder IC -- the Toshiba TA7628P integrated circuit (IC). It had built-in pre and power amplifier stages, together with a bootstrap pin, and external ripple filter control pins. The IC also has a built in recording buffer amp to drive the recording bias circuit, which is not used on this model, but is used on the KT-R1 and KT-R2 recorder versions. Since each chip was mono, two were required for stereo operation on this player. The power output of the chip is 0.6-watts per channel and powerful enough to drive a small loudspeaker, as the IC was initially intended for tape recorder and car audio applications, hence through a good pair of headphones, this little player can be very loud.

The cassette compartment also houses the radio module RP-S2, and in the image above you can see the contact points where the two devices interface. You can see further photographs of the tape transport in this multi-page article. An interesting feature of this player is that it has twin headphone sockets connected in parallel, thus allowing two people to listen to music simultaneously. It has a radio/tape selector switch, chrome/normal selector switch, an LED for the FM radio operation, and a second LED for the power level indication. There is a large clear window on the cassette lid, which is very useful.

Tape Controls

The full tape controls with cue and review facility made this player very unusual in the time. The tape deck mechanism and the push-button assembly is manufactured to a high standard.

Review

Toshiba manufactured a series of stereo players such as the KT-S2, and KT-S3 that were very similar in look and design. Many of the internal components were also identical to that used on the KT-S1. There was also the KT-R1 and KT-R2, which were the recording versions. On the recording versions, the yellow mute switch within the play button activated the recording function. This player is very much on par with the Sony TPS range in terms of build quality and manufacturing. However sound wise it is more superior with the twin high gain audio chips, and consequently chrome and metal tapes sound more crisp and sharp.

As you will see in the following sections of this article, the design of the audio chip is unique, and capable of delivering over half a watt (600 mW), however, the final output of this player is 40 mW (rms). In comparison, the Sony WM-D6C output is 30 mW per channel in a 32 Ω load. In the KT-S1, the high audio power output comes at a cost, and in this case, it is the high battery power consumption.

Cost/eBay

This was a very early 1980s stereo cassette player with a mid-sized production run, and of interest to Walkman collectors because it is in the same style. Superbly built, most of them should still be working today with a new drive belt. The price can vary considerably depending upon the condition and the number of interested buyers.

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