transferring cassettes to CD - Plusdeck 2C or other options

wrote in message
oups.com...

Wow, I never knew that azimuth stability was such a problem with
cassettes.

Its a very major problem, exasperated by the low tape speed.


How do you know how to adjust the azimuth - or how would a device know
what the correct setting is? Is there some fail safe way to tell, or
do you have to use your own ears?

The best way to adjust azimuth is to have a mono test tape, and adjust the
azimuth until tape heads tracking the top and bottom edges of the recorded
track reproduce waves with identical timing.

William's story about tape heads that split one of the tracks on the
cassette is very believable. It turned every track into a mono track by
having two narrow heads that split the track. The narrowness of each head
would hurt its dynamic range, but summing them together to create an
output signal would eliminate that problem.

I'd put my money on nulling based on minimizing the phase difference.
It is going to work well with less regard for program material HF content.

You're almost certainly right. The operative adjective is "less" -- I've
noticed that tapes without much HF content just don't want to "align".

William's story about tape heads that split one of the tracks on the
cassette is very believable.

I checked the Dragon service manual and confirmed this is the way it works.
However, if my life depended on explaining the details of the electronics,
I'd be dead pretty quickly.

wrote:
Wow, I never knew that azimuth stability was such a problem with
cassettes. Thanks so much for pointing that out.

Azimuth stability and speed variations are the main reasons for the cassette
being such a miserable format. Oh yes... and no reference tones for Dolby
decoding either (although some early cassette machines did have the ability
to lay down tones).

How do you know how to adjust the azimuth - or how would a device know
what the correct setting is? Is there some fail safe way to tell, or
do you have to use your own ears?

You have to use your own ears and peak for best high end. A scope can be
very helpful for mono material but only a rough guide for stereo material.
And the problem is that it drifts... the right angle at the beginning of
the reel may be way off by the end of the reel. God, how I hate cassettes.
--scott

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

Mike Rivers wrote:

The automatic adjustment looks at phase difference between the
channels and drives a motor which adjusts the head.

In order to do this, though, it has two or more channels for each channel
on the tape, so it can look at two halves of one track to determine the
angular error. This makes the automatic azimuth machines electronically
a good bit more complex.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

William Sommerwerck wrote:
William's story about tape heads that split one of the tracks on the
cassette is very believable.

I checked the Dragon service manual and confirmed this is the way it works.
However, if my life depended on explaining the details of the electronics,
I'd be dead pretty quickly.

I dunno if the Dragon uses the 4016 PLL chip as a discriminator, but that
used to be a common way to do that sort of thing. The data sheet for the
4016 explains it all.

And yes, the whole notion of PLL discriminator circuits came out of the WWII
radar effort. Some of Norbert Weiner's math went into them, but lots of
other guys helped.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Aug 7, 7:03 pm, "William Sommerwerck"
wrote:

In the Nakamichi, the outermost track (the one closest to the tape edge) is
split into two head gaps, each with its own amplification. The head block is
moved until the HF output of these heads peaks. (Or is it that the phase
difference is minimized?) Anyhow...

Anyhow . . . like I said, the phase. That's easier to detect (and
closer to absolute) than the HF peak.

On Aug 7, 7:11 pm, "Arny Krueger" wrote:

The best way to adjust azimuth is to have a mono test tape, and adjust the
azimuth until tape heads tracking the top and bottom edges of the recorded
track reproduce waves with identical timing.

That's the best way to adjust it to a standard, but the cassettes to
be played may not have been recorded with the heads set to that
standard. And the real problem is with instability of the tape
relative to the head, both when recorded and again when played.

For a "better than random" setup, making one adjustment before playing
a tape is probably sufficient, but it should be done for each tape.

Scott Dorsey wrote:
It's a cheesy car-style transport that mounts in a computer. It is not
a good way to get decent sound quality and it is not going to hold up to
heavy use.

Just go the Nak Dragon route. Your time will be radically saved because
you won't be having to redo anything, and the azimuth control is automatic
so you can do the work more or less unattended. Run it for a thousand hours
and you might need to replace the heads but that's just a normal thing.

Yoou do NOT use cleaner cassettes, you use the "Head, Red and Roll cleaner"
from Precision Motor works or something similar and a swab. And you do it
after every reel change. You can use 92% isopropanol in a pinch but it takes
a lot more elbow grease.

Don't waste your money on crap. Get a good deck either with manual or
automatic azimuth control.
--scott

Indeed, the Dragon was an exceedingly high-end consumer machine. But it
is expensive overkill for most people's old cassette collections. This
is especially true for most commercially recorded cassettes, which were
duplicated at high speed on tape stock that was run-of-the-mill or worse.

Paul in San Francisco

Paul MR wrote:
Indeed, the Dragon was an exceedingly high-end consumer machine. But it
is expensive overkill for most people's old cassette collections. This
is especially true for most commercially recorded cassettes, which were
duplicated at high speed on tape stock that was run-of-the-mill or worse.

The problem is that the high speed duplication tended to produce even worse
azimuth wander, and too many of those bin duplicators were run by sloppy
folks who were not careful about alignment. This, sadly, increases the
expense on your end when you're trying to get decent sound out of the junk.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."