Specifications

while the Extron transcoder blanked them. I consulted the input specifications for the Extron switcher
and found compatibility issues with the Key Digital's HD signals. In all fairness, I must point out that
the offsets and sync pulses are unlikely to affect your display; my projector provided lovely pictures
when I drove its RGB inputs directly. So I'm raising this issue only for any reader who may own an
Extron switcher similar to my own.
For those who may have an HD set top box that produces RGB-HV directly, Key Digital offers another
helpful product, a transcoder/switcher, model KD-XB, called the XBlaster. This unit has one VGA output
for RGB (the KD-CTCA2 has two outputs), one VGA input connector that accepts RGB-HV, and a
component video input that accepts 480p, 720p, and 1080i video formats. It isn't as versatile as the
KD-CTCA2, since it's intended to transcode the component video output of an X-Box or GameCube and
to provide the means to use a computer's monitor for game playing. For example, it produces negative
sync only, while the KD-CTCA2 produces negative and positive, switch selected; the Xblaster has no
switches. The XBlaster will output either RGB-HV or RGsB automatically based on the nature of the
signal at its component video inputs, and RGB-HV only from the VGA input connector. So it might be
possible to connect a progressive DVD player to the KD-XB's component video inputs, an RGB-HV HD
set top box to the KD-XB's RGB video inputs, and automatically transcode and switch. (The RGB input
has first priority; transcoded component video is outputted only in the presence of a signal at the
component video inputs.) Should you choose to try the Xblaster for this type of application, you should
communicate with Key Digital about your specific equipment configuration to verify compatibility before
buying.
The Key Digital KD-CTCA2 transcoder - with three caveats - can be a wonderful solution for the home
theater enthusiast who owns a display that requires RGB-HV or RGsB rather than component video. For
about a third of the cost of the Extron, you'll have a solution. Follow Key Digital's instructions first,
applying the recommended switch configurations for your source and display. Only if those all fail, and
only after you've confirmed your display's compatibility with RGsB by consulting its user manual,
should you try the undocumented switch settings I mentioned. The downsides of the Key Digital
transcoder are that if you own a CRT-based projector, HDTV's tri-level sync may cause a visible
problem, you'll very likely have to adjust your projector's color temperature, and in the event that you
own an electronic RGB switcher, like the Extron, you may have signal level compatibility issues.
The Interconnects
The Extron's input connectors are BNC and the Key Digital's are RCA, so I needed a new component
video cable for the connection between my new player and my new transcoder. I cannot stress enough
the importance of proper cables for your interconnects. Each video cable must have the appropriate
characteristic impedance - for video, 75 ohms - and appropriate distributed reactance to avoid placing
a destabilizing load on the output devices driving the signal down the line. Failing to provide these
basic characteristics, a deficient cable can cause ringing and smearing in the video. Too often, cables
are hyped like snake oil. Some cable companies, perhaps to justify outrageous prices, make all kinds of
fantastic claims. I prefer cables that are well made with quality materials and simply perform the task
for which they are intended: conveying the signal from one electronic device to another without
adversely affecting the quality or character of the waveforms. For this deceptively simple task, I choose
the cables offered by BetterCables , reasonably priced, high-performance interconnects that I've been
using for years. For the new connection between the Denon player and the Key Digital transcoder, I
needed a one-meter long component video cable equipped with 75-ohm RCA connectors on each end.
My choice is the Silver Serpent . (BetterCables also makes quality breakout cables, handy for those
who may have taken an interest in Key Digital's transcoder.) Compared to conventional cables,
BetterCables provides higher bandwidth and is very well behaved. Subtle details in the video become
more apparent when compared to conventional video cables. In other words, it's completely
transparent to the signal, just as it should be. Highly recommended no matter what other equipment
choices you make.
The Audio
The need for upgrading here was clear, and finding the right solutions was much easier than for my
video chain. In my Pseudo-EX piece, I described how it was possible to reconfigure an existing Dolby
Digital 5.1 system to perform 6.1 decoding by adding a Dolby Surround decoder to a digital audio
decoder's analog surround outputs. My trusty old Shure HTS-5300 analog Dolby Surround decoder
worked very well with my B&K AVP-3090 digital decoder/preamp, but three issues remained
unresolved. I could not adjust independently the time delay to the center surround speaker. If the
delays aren't right, imaging suffers and the audible locations of sound sources in the surround channels
become vague and sloppy. That problem's easy to resolve, virtually all respectable 6.1 decoders or
receivers permit an independent delay setting for each loudspeaker. An inconvenience was the 3090's
inability to automatically detect DTS; that, too, was easy to resolve since any DTS-capable
replacement will switch automatically as it recognizes the incoming audio bit stream. And the AVP-3090
did not offer THX re-equalization; correcting that deficiency required a little more selectivity.
Page
5
of
7
DVDFILE.COM: Mr. Blandings Builds his Dream Theater
4/7/2003
http://www.dvdfile.com/news/special_report/tech/mrblandings/upgrades.html