[Vintage-Audio] Reel to Reel Info

[Mark - AA6DX]

Howdy Y'all
http://home.flash.net/~mrltapes/
This site, which has the data from the Magnetic Reference Library, has quite
in depth information on the reel to reel recorder alignment, and set up.
Many items are presented in Portable Document Format (PDF), so it is advised
to have Adobe Acrobat Reader, or its equivalent, on your computer.   Be
prepared to spend some time, as it well written and documented, making for a
good read!  I have not tuned up a tape recorder since about 1983, so I
enjoyed getting a refresher course!  I remember the automated radio stations
that ran banks of reel tapes, and would like to know how many heads I have
lapped!   Used a plate of glass, varying degrees of emery paper, and then
polished with a jeweler's rouge cloth.
As to crosstalk (unwanted signal leakage from one signal path to another), I
was often replacing headblocks, and so forth, and had to adjust the az and
zenith, the wrap, etc ..  and the positioning of the tape came as part of
the game, but I don't disagree with WBob and all.  We used to get a lot of
poorly recorded ad spots from hither and yon, many small, and I mean small,
market stations used home quality stereo machines, which the jocks beat to
death. Golly, my forgettery is working swell!
But, to show I am not totally out of it (yet), may I refer you to this
Internet site.
http://c2.com/cgi/wiki?ReelToReelTape

Here's a great source for more info:
http://www.churchsoundcheck.com/tra.html
And a sample from this site:
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There are five basic head alignment checks to make. They are azimuth,
zenith, wrap, height, and tape-to-head contact. Azimuth is probably the more
critical alignment, because this is what will cause the phase cancellations.
An improper azimuth adjustment will show up on playback through phase
cancellations, because in effect it creates a time discrepancy between the
tracks.
Azimuth is the alignment of the heads perpendicular to the direction of tape
travel. If the azimuth is misadjusted, any program recorded on both tracks
will be played back slightly out of phase.
Zenith is the alignment of the heads in the same plane as the tape. For
example, the bottom of the head can be kicked out too far, which may cause
the top tracks not to fully contact the head, and would cause the tape to
ride up on the head, snapping back down occasionally. The zenith can also be
misaligned so that the top of the head is shoved too far out. The head
should be aligned so that the tape rides against it with smooth contact to
the entire surface.
Wrap is the alignment of the head so that the tape contacts the head at the
center, aligned with the head gaps. The wrap adjustment causes the head to
swing in an arc centered on the middle of the head, and moves the center of
the head from the left to the right of center, depending on which way you
adjust the screw.
Head height is adjusted so that the tape rides perfectly centered from top
to bottom on the head. You can tell this immediately just by looking at the
tape as it rides across the heads.
Tape-to-head contact is just that - the head should be positioned far enough
into the tape path to ensure good contact with the tape. If it were too far
back, insufficient pressure would cause playback to be inconsistent.
Other than a cursory look, you probably won't need to adjust any alignment
settings on the erase head. Your first alignment will be on the reproduce
(repro) head, followed by a brief confirming check of the record head by
switching the machine to the selective synchronization status. A more
precise setting of the record head can be made during the first stages of
the record electronics alignment.
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Cheers ... back to the house remodel .. Far West Mark
(We hauled a two-ton Roberts recorder, last of my reel machines, to the
church bazaar yesterday!)