From: Patent Tactics, George Brock-Nannestad
Chris @Eugene wrote
> The normal correct procedure, according to service
> manuals, is to adjust for maximum signal strength,
> before "fine-tuning" with a Lissajous pattern for
> phase relationship. It is possible to get the
> correct Lissajous pattern at less than maximum
> signal strength azimuth adjustment.
> Usually what I do is watch the signal strength
> on an audio voltmeter or the o'scilloscope. Adjust
> for maximum amplitude, then you can "tweak" it
> very, very slightly for the proper Lissajous
> Hope this helps.
----- this is what we all do. However, Richard took the signals from the
"edge" tracks (i.e. those almost ½ inch apart), realizing that the 1 kHz
signals (a _low_ frequency) were in phase in all channels, and generated the
Lissajous from these. This is a good (and novel) way to obtain precision. The
need for obtaining a maximum amplitude reading does not arise at this low
frequency - you cannot tilt the head so much that you get an erroneous
"lower" maximum at this frequency, unless it is a monitoring tape at very,
very low speed.
Thank you, Richard, for this neat trick!
> --- "Richard L. Hess" <[log in to unmask]>
> > Hi, all,
> > Last night I was transferring a 4-track, 1/2" tape
> > and it only had
> > 1kHz tones at the head and the azimuth didn't sound
> > right. It
> > appeared the tones were recorded as part of the same
> > session and not
> > an add on. But there were no HF tones.
> > I used the two outer tracks and fed that into the
> > vector display
> > software and it was pretty easy and definitive to
> > get a null in the
> > Lissajous figure.
> > Just thought I'd pass it along FWIW in case you
> > already weren't doing
> > this type of thing. Remember, azimuth errors can't
> > really be fixed in post.
> > Cheers,
> > Richard
> > Richard L. Hess email:
> > [log in to unmask]
> > Vignettes
> > Media web:
> > http://www.richardhess.com/tape/
> > Aurora, Ontario, Canada (905) 713 6733
> > 1-877-TAPE-FIX
> > Detailed contact information:
> > http://www.richardhess.com/tape/contact.htm