Aiwa HS-PX101 Service Manual

The HS-PX101 (also known as HS-PX700 and HS-PX10 and HS-PX101A), was a stereo cassette player manufactured by the Aiwa Corporation of Japan in 1987. It had an auto-reverse transport mechanism with feather-touch full-logic controls. It also had Dolby B and C noise reduction systems, including Dynamic Super Loudness (DSL-EX) system that allowed the user to vary the equalization through a pair of slider controls. It had some useful features such as rechargeable battery providing 2-hour operation time, in-line wired remote control (RC-R101), metal tape compatibility, and music sensor. Its dimensions were 75.3 mm × 118.5 mm × 25.8 mm, and mass 214 g including batteries.

There is a huge amount of marketing information about this model, including graphs, and lofty boasts, however let us look under the hood so to speak. The main audio integrated circuit (IC) is the TA8115F by the Toshiba Corporation. This was used in a huge number of stereo cassette players by a majority of manufacturers in the 80s and 90s. It has built-in preamplifier blocks for the heads, and headphone power amplifiers providing the usual 15 mW per channel (EIAJ/40 Ω). This was very much typical for stereo cassette players utilising this IC during this time.

Since the audio IC is nothing special, most of the magic must be occurring between the preamplification and power amplification stages. In this case, they use NJM2065M IC to provide Dolby B and C noise reduction, which was very forward thinking for the time. Interestingly, they had to use two of these ICs as one IC caters for only one channel. The output of the Dolby ICs is then fed to IC4 (TK10595M), by Toko America Corporation. This IC is responsible for the dynamic super loudness that tends to confound audio buffs out there. Looking at the internal circuitry of this IC, we can see it has a number of simple op-amp blocks configured for active filtering.

The HS-PX101 will definitely sound good providing you use a good pair of headphones. The original supplied headphones were Aiwa HP-MR1, which were high-fidelity headphones. This is a nice bit of electronic engineering that is unusual due to the DSL function, and consequently, commands a high price when for sale at auction sites.

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