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From: fish@ihlpg.UUCP (Bob Fishell)
Newsgroups: net.video,net.audio
Subject: Radio Hack's MTS Receiver
Message-ID: <1453@ihlpg.UUCP>
Date: Tue, 19-Nov-85 20:07:30 EST
Article-I.D.: ihlpg.1453
Posted: Tue Nov 19 20:07:30 1985
Date-Received: Wed, 20-Nov-85 08:32:37 EST
Distribution: net
Organization: AT&T Bell Laboratories
Lines: 64
Xref: watmath net.video:1676 net.audio:6564

***  E  A   T          IT               ***

After a year's delay, Radio Hack finally began selling their MTS stereo
decoder.  After looking at what MTS-ready TVs and VCRs cost, I decided
to get one, at a cost of $140.

The unit looks like a miniature FM receiver, with a dull-metallic front
panel and fake wood-grained cabinet.  Tuning is analog, with a switch
that controls VHF low(2-6), VHF High(7-13), and UHF bands.  There is
no superband VHF band selection, so the unit cannot be connected
directly to most cable systems.  There are switches for stereo/mono
recepion, secondary audio broadcast, and a "stereo synthesizer," which I'll
get to later.  Pilot lamps behind the dial indicate the presence of stereo 
or secondary audio signals.  There is a tape monitor loop, and a switch
to control it. There are volume and tone controls, and
there is also a 1/4" headphone jack.

The rear panel has both input and output connections for the video
signal. 300 and 75-ohm connectors are available for VHF.  There are
two pairs of audio jacks for the tape loop. The unit has an integral
power amp which is connected via push-contact  terminals to a pair
of speakers.  Hack will throw in a pair of 4" speakers w/enclosures for
an extra $10, if you buy them with the unit.

The amplifier is rated at 2.5 w/ch, which is no good if you intend to
drive anything other than a pair of squaukers such as those which are
optionally sold with the unit.  THD is rated at 1%; channel separation
and S/N are not great, but are acceptable.

I connected mine to my stereo system through 330-ohm resistors connected
to the speaker jacks.  When I want to watch TV without my sound system
on, I can switch the speaker outputs to another, small amplifier and a
pair of bookshelf speakers I had laying around (Hack didn't provide the
switch, I did). Again, the unit is too underpowered to drive real speakers.

The sound quality is decent, but not as good as FM stereo.  Occasionally,
you can hear compander noise.  Since this occurs on some broadcasts and
not others, I suspect this is due to an imbalance between the compression
applied to the L-R signal and the unit's expander.

The stereo is exaggerated; I suspect the L-R signal is boosted disproportionally
in order to compensate for the mediocre channel separation. Again, this
could just be a mismatch on the compansion.  The audio track on "Amazing
Stories" sounded pretty good last week.  The pseudo-stereo that's broadcast
when they're not pumping true stereo is not impressive, but it's not as
objectionable as the "stereo synthesizer" that's built into the unit.
This circuit is evidently nothing more than an unbalanced equalizer which
sends parts of the audio spectrum to one channel, parts to the other. The
effect is a bit like listening to cross-phased speakers, something that
I don't like.

Altogether, I think the unit is worth $140, and provides a welcome alternative
for consumers that want MTS TV, but aren't willing to scrap their perfectly
good mono TVs and/or VCRs just for the  upgrade. Still, Hack could've made
this box a little better.  The amplifier is a joke; they should just have
provided preamp outputs.  Separate bass and treble controls would have been
nice, too, instead of that moronic "tone" control.  The "stereo synthesizer"
is worthless.  Finally, I'd like to have a control by which I could adjust
the L-R signal in order to provide proper balance.
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/  \
\__/
				Bob Fishell
				ihnp4!ihlpg!fish