pioneer sm-q300

The SM-Q300 model was the next in the line of stereo receivers working in the "multicast" system. Another and the most powerful, as the power amplifier worked on 6BQ5 / EL84 tubes in an automatic bias system. In such a system, Pioneer used the 6AN8 as a driver tube (and not the 12AX7 / ECC83 later in such constructions). Both the 6BQ5 and 12AX7 were made by NEC. The amplifier could be loaded with speakers with a resistance of 4, 8 or 16 ohms. The tuner layout was built in the same way as in the SM-G204 model. The only difference was the dual tube 6G-E12A "magic eye" tuning indicator which replaced the two 6E5 tubes. The difference in the low-frequency path was the input for a dynamic microphone, but it could work only interchangeably with turntables. However, there was one element that distinguished the model from other stereo tube receivers of those years - a quad-coupled volume potentiometer. Such solutions began to be used in transistor designs only in the 70's, and in the most expensive ones. In the SM-Q300, the potentiometer regulated the input signal and the output signal of the 12AX7 / ECC83 tubes in the second stage of the band control preamplifier. And there was one more curiosity about this device. Triple MODE BLEND potentiometer. What was usually done on the switches, this time Pioneer's designers did on a potentiometer. On the front panel you can see that in the leftmost stereo position it works normally, in the right extreme stereo it is inverted, i.e. the Left channel is played on the Right channel (and vice versa). However, in the middle position, the receiver works mono. As a more expensive and luxurious model, the rear of the device had a remote balance control. The SM-Q300 looks very stylish, the silver front, pastel frame and black plastic knobs finished with silver and gold rings make a very nice whole.

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