Those pieces were produced by Pioneer, shortly after their acquisition of Phase Linear. They produced their Champagne line to match the appearance of their Phase Linear Series II gear. The finishes were a bit fragile and easy to mar. The cassette decks with auto-reverse were problematic, because of the rotating rec/play head package. Corners were cut in the production, to reduce costs, due to the increase of shipping costs of the day. Sound quality was good, and features were nice.
Units from the Champagne series are rare, because they did not sell well. Both this series and the acquired Phase Linear Series II went out of production fairly quickly. The buying public tends to be fickle, and everyone was turning to black gear at the time.
3s and 4s were rather low in the product line pecking order, with 9s being top of the line.
Welcome to AK.
Enjoy,
Rich