Make a DAT alignment tape?

[spud]

Archived from groups: rec.audio.pro (More info?)

Can I make a DAT alignment tape? I have a known to be perfectly good
Tascam DA30 MKII, a scope and I saw the guy hook up the test probe.
Using wavelab what kind of a wave at what level would I generate to
make the tape? The guy just help a swab with cleaner on the back of
the head and waited till the output looked like a square block. Thanks
as always, s.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

No. Alignment tapes are not just a blank recording. A recording contains
tracking data that enable the DAT player to follow the recorded tracks and
adjust itself to keep the playback head perfectly on track. Alignment tapes
have this information removed so that on playback the heads are free running
and don't lock onto the recorded information. Because the alignment tape is
precisely made, the angle, start and finish points of the recorded tracks is
exactly where it should be, and any misalignment of the playback machine
will show a distorted waveform, a bit like a television with no vertical or
horizontal hold signals.


Gareth.


"spud" <mrmasontrashdjp@yahoo.com> wrote in message
news:l5jfs05u420nlu12qoacafagjinjrgo72q@4ax.com...
> Can I make a DAT alignment tape? I have a known to be perfectly good
> Tascam DA30 MKII, a scope and I saw the guy hook up the test probe.
> Using wavelab what kind of a wave at what level would I generate to
> make the tape? The guy just help a swab with cleaner on the back of
> the head and waited till the output looked like a square block. Thanks
> as always, s.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"spud" <mrmasontrashdjp@yahoo.com> wrote in message
news:l5jfs05u420nlu12qoacafagjinjrgo72q@4ax.com...
> Can I make a DAT alignment tape? I have a known to be perfectly good
> Tascam DA30 MKII, a scope and I saw the guy hook up the test probe.
> Using wavelab what kind of a wave at what level would I generate to
> make the tape? The guy just help a swab with cleaner on the back of
> the head and waited till the output looked like a square block. Thanks
> as always, s.

No, you can't. The alignment tape contains not only accurate tracks, but
various kinds of inaccurate tracks as well. You need more than just the
precise eye pattern (and you also need an eye pattern that is MUCH more
precise than a 'perfectly good DA30' will give you.

I will tell a story. Someone in China bought a lathe somewhere, which had
a very good leadscrew on it. They used it to make the leadscrew for a
lathe, which they sold to a lathe making plant. The lathe there was used
to make a leadscrew for a lathe, which was then imported and sold at Harbor
Freight, and it was totally useless because it had been calibrated against
an inaccurate reference. This is why you need a first generation standard
tape, and it's part of why the first generation standard tape is so expensive.
--scott
>


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[spud]

Archived from groups: rec.audio.pro (More info?)

On 21 Dec 2004 11:22:48 -0500, kludge@panix.com (Scott Dorsey) wrote:

>"spud" <mrmasontrashdjp@yahoo.com> wrote in message
>news:l5jfs05u420nlu12qoacafagjinjrgo72q@4ax.com...
>> Can I make a DAT alignment tape? I have a known to be perfectly good
>> Tascam DA30 MKII, a scope and I saw the guy hook up the test probe.
>> Using wavelab what kind of a wave at what level would I generate to
>> make the tape? The guy just help a swab with cleaner on the back of
>> the head and waited till the output looked like a square block. Thanks
>> as always, s.
>
>No, you can't. The alignment tape contains not only accurate tracks, but
>various kinds of inaccurate tracks as well. You need more than just the
>precise eye pattern (and you also need an eye pattern that is MUCH more
>precise than a 'perfectly good DA30' will give you.
>
>I will tell a story. Someone in China bought a lathe somewhere, which had
>a very good leadscrew on it. They used it to make the leadscrew for a
>lathe, which they sold to a lathe making plant. The lathe there was used
>to make a leadscrew for a lathe, which was then imported and sold at Harbor
>Freight, and it was totally useless because it had been calibrated against
>an inaccurate reference. This is why you need a first generation standard
>tape, and it's part of why the first generation standard tape is so expensive.
>--scott
>>
Thank you for the story, Scott.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

The guy just help a swab with cleaner on the back of
> the head and waited till the output looked like a square block. Thanks
> as always, s.


The above is actually a good way to test for dirty heads, though nothing
whatsoever to do with alignment. Just play any tape and observe the RF
waveform with a scope. If they are very dirty you will be able to see the
waveforms shifting around, or be able to see that one head output is much
lower than the other, or missing altogether. (A DAT head is actually 2
heads diametrically opposed). A good signal will contain 2 solid square
looking waveforms - head A followed by head B. (one is usually a bit lower
than the other, nothing to worry about).

Gareth.