[TechAssist] Re: Best way to clean a head.
- From: "OrpheusComputing.com Repair" <techassist@xxxxxxxxxxxxxxxxxxxx>
- To: "TechAssist" <techassist@xxxxxxxxxxxxx>
- Date: Mon, 26 Nov 2001 08:09:04 -0600
Yeah, that's sort of what I said in an earlier email...it can
show on paper in many cases, but not an audible difference
because the specs are so good to start with. Back when hi-fi
audio specs were checked and included in reviews (about 15yrs
ago in "Stereo Review" and "High Fidelity" magazines, and in
the owner's manuals from 10-15 yrs ago, usually the EP speed
had about 1khz more on the high end, and less than a 3db
increase on S/N ratio. When dealing with SN ratios of above
75db, of course you won't hear a difference of 3db, and with
frequencies of ~20khz - 21khz, you won't notice only a 1khz
difference. Usually these differences can only be seen on
state of art equipment because the difference of the specs
are within the +/- error margins of typical test equipment.
The Hi-Fi audio >tape to head velocity< is 5.8 m/sec (19.03
fps) in either EP or SP only. It's slower at SP, but can't
be the same for both speeds, obviously because the
tape is moving at a different speed (1.3 ips LINEAR tape
TRAVEL speed in SP vs .4375 ips in EP), but the drum is still
turning at 1800rpm. Yesterday I mentioned 19 fps, but I
can't recall if that was for EP or SP...I THINK it was EP,
but I could be wrong on that. I've looked all over the place
the past hour and cannot find a simple chart for SP vs EP
writing speeds! I can't find anything on the subject.
Yes it's as good as CD, that's why I used to record music
on VHS tapes instead of a cassette deck. Hard getting
that VCR into the car though....... :-)
-Clint
Happy Thanksgiving &
God Bless Us All
Clint Hamilton, Owner
http://OrpheusComputing.com
http://ComputerHardware-ConsumerElectronics.com
sales@xxxxxxxxxxxxxxxxxxxx
Fax: 209-882-9602
TechAssist Administration
http://tech-assist.org
techassist@xxxxxxxxxxxxx
----- Original Message -----
From: "Dennis Viereck" <wa6ati@xxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, November 26, 2001 2:07 AM
Subject: [TechAssist] Re: Best way to clean a head.
I did tests when HI-FI first came out. It really made no
difference at all if
the tape was recorded in SP or EP for sound quality. Dynamic
range was greater
than 80 db and un-weighted wow and flutter was under .008%.
There was no
measurable difference between SP or EP. The HI-FI tape to
head velocity is
still 5.8 meters per second.
The only measurable problem I've seen on these machines is
tangential
switching noise from time to time. This is caused by a gap
between the RF
envelopes between HI-FI head "A" & HIFI head "B". Usually on
machines that are
worn.
Don't sell VHS HI-FI short. It is very close to CD quality.
Dennis
Ledstiles@xxxxxxx wrote:
> In a message dated 11/25/2001 11:44:38 AM Pacific Standard
Time,
> jeff@xxxxxxxxxxxxxxxxxx writes:
>
> <<
> > there....the hi-fi audio quality is actually better in
most
> > cases @ EP (slowest speed) because due to the rotation
of the
> > head drum, it is the same direction of the tape path; so
if
> > you slow that down to EP, the tape of course then is
going
> > slower therefore the 'writing speed' is increased. It
is
> > usually not noticeable to ears since the audio specs are
so
> > good to begin with, but it does show on paper. Usually
ab >>
> I don't buy it. audio quaility is always better in sp speed
vers ep speed.
> Larry
> N.C.S.
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