HST-D501CDM inside Look

Opening the top and one side panel of the HST-D501CDM unit shows the huge amount of electronic engineering that goes into this hi-fi system. The board attached to the base is the power amplifier, whilst the vertically oriented panel is the main board with an exotic assortment of integrated circuits. In addition, there is electronic circuitry on the PCB connected to the front panel.

The STK4152II is a thick film hybrid IC, for audio frequency power amplifier applications, manufactured by the Sanyo Corporation. Amplifiers with this IC usually provide good bass and tone, and they were used in many different high-end amplifiers.

As you can see, this hi-fi system has a conventional mains transformer to power the audio amplifier circuits. This is sometimes far better than the nasty switched mode PSUs that modern units tend to have, however this transformer is very heavy.

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