Pioneer CK series

The "CK Series" was a group of mini stereo components (and speakers) made by Pioneer. I believe they're from 1983 because that's the date on the service manual. They were some of the best-sounding portable systems of that era. Collectors often refer to them as the CK-3, CK-5, CK-7, or CK-11, but it's a bit more complicated than that, because people could mix and match the components to create their own custom set.

Tuner/Amps (receivers):

As you can see in the photograph below, there was a choice of 3 receivers: The FA-C3, the FA-C5, and the FA-C7T. Each of them have the same power ouput (12.5 watts per channel RMS at 6 ohms from 60 to 20,000 Hz at 5% THD). The difference is, the FA-C7T has a digital tuner, while the other two have analog tuners. Also, the FA-C5 and FA-C7T features a graphic equalizer, while the FA-C3 has bass and treble sliders.

And if someone wanted more power, they could add the M-C11 Stereo Power Amplifier, which boasted 30 watts per channel RMS at 6 ohms from 40 to 20,000 Hz at 5% THD.

Tape decks:

Here are the 3 different tape decks offered:

• CT-C9W: Twin-deck
• CT-C8: Autoreverse
• CT-C3: Entry-level

Speakers:

For speakers, Pioneer offered the model CS-C7 which is a coaxial 2-way system with 3.5 inch round speaker mounted in the center of a large flat woofer. Then there's the model CS-C11 which is nearly identical, but with a ribbon tweeter added on top. Both models are rear-vented, and they also have special foam "Acoustic Dampers" on the side.

NOTE: There was another speaker, shown below, that was sold only with the "CK-3" system.
It is called the CS-C3 and it has a traditional round 12cm woofer and a 2.5cm ceramic tweeter.

Finally, there was even a turntable available (the PL-C7).