[TechAssist] Re: Best way to clean a head.
- From: Dennis Viereck <wa6ati@xxxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 26 Nov 2001 11:32:26 -0800
Ed:
Yes. As tape speed increases the better frequency response will be the ultimate
result. This will increase the number of octaves that can be placed on the
tape. On a standard reel to reel tape machine 15 ips would achieve an
outstanding frequency response. But you sacrifice the amount of time you have
by the physical limitations of the tape length. I think a standard T120 tape we
only have 240 feet of tape. By helically writing on the tape rather than a
linear track we can take advantage of the short tape length and place it
diagonally on the tape. This way we can increase the head to tape writing
speed.
At over 19 feet per second we have so much bandwidth we can record an FM R.F.
spectrum. In the case of HI-FI, I believe it is 1.3 mhz for L-R and 1.7 mhz for
L+R.
Dennis Viereck
Tel-Tek Electronics wrote:
> Dennis;
> Would speed of VHS tape not effect the audio the same way that the old
> Reel-to-reel recorders worked. Use to replace the spindle size to increase
> the tape speed. More tape per inch, better frequency response?
> Although I agree that audio to the average person will not improve with one
> speed over another, since the audio is pretty good at any speed.
>
> -Ed-
> teltek@xxxxxxxxxxx
> TEL-TEK ELECTRONICS.
>
> ----- Original Message -----
> From: "Dennis Viereck" <wa6ati@xxxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Monday, November 26, 2001 10:09 AM
> Subject: [TechAssist] Re: Best way to clean a head.
>
> >
> > Clint:
> > If you did the math you will find that the HI-FI head to tape velocity
> > should increase or decrease the overall velocity by less than 1 inch per
> > second. This insignificant amount is hardly enough to worry about when
> > the compared to the actual velocity is 19.03 fps. This is only 0.00045%
> > difference. Hardly enough to get any measurable difference in audio
> > quality.
> >
> > Dennis Viereck
> >
> > "OrpheusComputing.com Repair" wrote:
> >
> > > 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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