| Very few Betas were equipped with linear stereo. This added capability was mostly limited to the Sony professional Betas, these models included the GCS-50, SLO-323, SLO-325, SLO-383, SLO-420 and the SLO-1800 production duplicator made for making pre-recorded movies. The GCS-50 and SLO-1800 were also SuperBetahi-fi stereo. The GCS-50 was the only Beta that permitted recording separate audio information on the two linear tracks independent of the Betahi-fi. The SLO-1800 professional duplicator was originally released with linear stereo audio tracks in addition to the Betahi-fi. Presumably this was done to accommodate the Marantz VR 200 which was introduced just prior to Betahi-fi. In mid-production Sony later revised the SLO-1800 and removed the linear stereo. This was done to save cost and because so few consumer machines would actually use it. This didn't exactly thrill Marantz. They never introduced another Beta with their name on it. (The VR 200 was made for them by Sanyo.) Linear stereo is recorded by two, side-by-side stationary audio heads located at the upper surface of the ACE assembly (block for the Audio and Control pulse recording and audio Erase). Just like a reel-to-reel audio recorder a magnetic signal is recorded on the tape as it travels past these stationary heads. In regular monaural recording there would only be one single audio head. Betahi-fi stereo on the other hand, is recorded elsewhere, by the spinning video heads. This was accomplished by engineering a slight alteration in the video recording process. A space was made in the signal for inserting four FM carriers to record stereo sound. As long as everything stays in place the FM doesn't disturb the video information. Due to the high speed of the spinning heads this system produces nearly perfect stereo. Things like wow, flutter and tape noise are virtually eliminated. Beta could do this because the larger video drum produced a longer, fuller magnetic signal. VHS could not duplicate Betahi-fi because there wasn't enough room in its video signal to insert any additional information. |