VCRs with 2, 4, 6 or more heads – what is the difference?
A single pair (2) of heads is needed for basic record and playback. With more heads, various aspects of these functions can be optimized to improve picture quality – usually for the special effects like CUE and REV. For example, a 4 heads are usually needed to produce decent quality playback in CUE and REV modes for SP recorded tapes. Another set of heads is required for HiFi audio. The only possible difference for record or at normal playback speeds is in picture quality since with 4 or more heads, head widths/gaps can be better optimized for each speed. For example, a wide track width can be used at SP speed and a narrower one for EP speed. Which VCRs do this, I have no idea. In fact, such differences might only be visible to the average viewer in an A/B comparison under controlled conditions. The stability of the video playback has nothing to do with the number of heads. A jumping picture during playback is due to a servo system problem. With problems of this type particularly on a
