Updated: April 2006
Panasonic (MEC) 180DVB22 8" EM focusing tube
For all intents and purposes, CRT’s come
in three sizes; 7, 8, and 9”.
Sony 7” tubes have a useable 5.5”
raster, but we’ll get to that later).
The measurement is taken from corner to corner on the front of the tube face.
Different manufacturer's have been known to rate the same tube as slightly
different in size however. To avoid confusion, most enthusiasts (and this site
as well) always refer to tube sizes by their actual size. For example, we
consider a NEC PG to have 8" tubes, not 7" as NEC sometimes would lead you to
believe as the tubes are actually the same size as in the higher end NEC XG
models. (Who would have ever thought that a manufacturer would
downgrade their specs on purpose?).
The larger the
tube size, the more resolution the
projector tube will be able to display
as the picture that is being projected
onto a large screen starts from a larger
In general, a larger tube
will also produce more brightness.
Something to keep in mind if you want to have an especially large screen.
Naturally, a larger tube also costs more
to make, which is why 9” projectors are
expensive to buy and expensive to
In general, most video-only and
entry-level data grade projectors are
7”. Mid grade projectors use 8” tubes
and the top of the line are 9”.