Stereo VCR plays some stereo tapes as mono

I have two stereo VCR'S connected. VCR 1 is an older Sears 2 head unit,
VCR 2 is a newer, 4-head unit. VCR 1 has the antenna going into its
coax connection, and is connected to the composite (i.e.
yellow/white/red) audio/video connections of VCR 2. VCR 2's composite
audio/video is output to the tv and stereo speakers. I have them set up
this way to take advantage of VCR 1's apparent greater sensitivity to
local broadcast channels, using one of those WalMart adjustable
antennas going into a 12db amplifier box.

Here's the odd thing - I get a great stereo image off the antenna -
i.e. antenna>amplifier>VCR1>VCR 2>receiver/speakers. I get a great
stereo image playing a tape in VCR 1 (again, going through VCR 2 before
hitting the speakers). However, playing a broadcast quality country
music video video (made for tv station broadcast) that sounds big as a
house when played in VCR 1, obviously is coming out mono from VCR 2.
VCR 2 *does* play other tapes in stereo, no problem.

Why would this be? When played in VCR 1, the signal has to go through
VCR 2 to get to the speakers, so why would VCR 2 not play this
particular video in stereo? Is there more than one kind of stereo
signal on VHS tapes? I would have thought they'd all be standardized.

Thanks.

 

if its a 2 head unit then it'll be linear stereo, not fm helical scan
hifi stereo like the newer unit. for hi fi stereo you need minimum 4
heads.
-B.

 

They are. But if there is any interchange problem between
the two VCRs, it might not be bad enough to see on the screen,
but it may be bad enough for the VCR to abandon trying to read
the FM stereo tracks, and fail-over to the mono linear track.

 

There is Hi-Fi stereo, and there is linear stereo. The Hi-Fi stereo is
embedded with the video, while the linear stereo has it's own "lo-fi"
recording head (like a cassette deck) and is recorded in its own track.
Are these Hi-Fi or linear stereo recorded tapes? How are your AUDIO
SELECT switches set?

 

Ah so. So, there *is* more than one variety of stereo.

 

Only a few professional VHS machines had linear stereo.
I've never seen a consumer VHS VCR with linear stereo.

 

You didn't reveal the make/model of your VCRs, but if they
are typical consumer machines, the likelihood of them having
linear stereo heads ranges from slim to none. Only a few pro
VHS VCRs had linear stereo that I have ever seen.

 

Oh, there were lots around in the budget market in the late eighties.
I had a Hinari one which had linear stereo. I suspect they were trying
to cash in on people not knowing the difference between 'stereo' and
'hi-fi' tracks...

Steve

The Doctor Who Restoration Team Website
http://www.restoration-team.co.uk

 

They exist(ed). There were a lot of commercial tapes with linear stereo
tracks before the engineers figured out how to kluge HiFi sound into VHS.

 

I had a consumer VHS in the 80s with linear stereo. I remember
watching Purple Rain with it hooked through the stereo. Woo Hoo!

 

Early model Mitsubishi SVHS (consumer models) VCRs had linear stereo.
But all late model standard VHS VCRs are linear mono.

Many Beta VCRs had linear stereo.

 

The fact that his old 2-head (non Hi-Fi) VCR was stereo is in
opposition to this statement.

Looks like VCR #1 was playing back a stereo linear track, while
his newer 4-head VCR #2 played this track in mono. Only way I
can see this happening.

 

I've seen marginal interchange problems cause the embedded FM
"Hi-Fi" recovery to fail when it would still reproduce the picture.
The fail-over is to use the mono linear track. (Or the stereo linear
track played with a single-gap head, rendering it monaural.)

 

Since some have inquired about brands/models, VCR 1 is a Panasonc labled
"4-Head Hi-Fi Stereo OmniVision" model # on the back is PV-V4520.

VCR 2 just says Sears Roebuck with some lengthy model number on the back
that I'm guessing isn't significant. I'm guessing it was one that was
rebadged under various brands. It's a front loader, probably from the
mid-late 80's, but that's just a guess. Among other switches, has a selector
switch for Dolby. Pretty hefty machine, probably weighs 25 lbs.

 

Hmmm...you originally said that VCR #1 was an old, 2-head model, and
that VCR #2 was the newer 4-head VCR.

Which one is it?

 

"Doc"s original post said that the older #1 VCR would play his
particular stereo tape in stereo, while the newer #2 VCR would
play it in mono (while playing other tapes in stereo).

 

Well, that settles it. If it has a Dolby switch, it is almost certainly
linear stereo, not HiFi stereo. Your VCR 1 is recording stereo HiFi in
the video, and a longitudinal mono track. Your VCR 2 can't play the
HiFi tracks, and plays only the longitudinal mono track.

Yet, in the E-E mode (listening to air or VCR 1 THROUGH VCR 2), it will
pass a stereo signal just fine.

 

That wasn't my question (and you are not Doc.)

In his first post, he wrote: "I have two stereo VCR'S connected. VCR 1
is an older Sears 2 head unit, VCR 2 is a newer, 4-head unit."

Then in his latest post he said: "Since some have inquired about
brands/models, VCR 1 is a Panasonc labled "4-Head Hi-Fi Stereo
OmniVision" model # on the back is PV-V4520. VCR 2 just says Sears
Roebuck with some lengthy model number on the back that I'm guessing
isn't significant. I'm guessing it was one that was rebadged under
various brands. It's a front loader, probably from the mid-late 80's,
but that's just a guess. Among other switches, has a selector switch for
Dolby. Pretty hefty machine, probably weighs 25 lbs."

It seems that the latter is a reversal of the former.

My "guess" as to what is happening is based on the wiring description
he gave in his first post.

 

If his VCR #1 is an older 2-head VCR (as his original post suggests)
how is it operating in Hi-Fi mode? More likely, his VCR #1 is playing
the linear stereo track, and the Hi-Fi model VCR #2 only has a mono
linear track.

 

Why would you think it was incapable of HiFi mode?