For whatever it is worth, here is a brief description of typical tape
Wrap = twist the head on it's axis, as looked at from above
Azimuth = the angle of the head ad looked at from directly in front of
Zenith = the angle of the face of the head as looked at from above (
that is, is the bottom of the head parallel with the top of the head, or
is the bottom 'sticking ' out further or less than the top of the
This is simplistic in description at the very least, but may help you.
All / any of these adjustments, it incorrect, will make for very poor
sound. An expert is really required to do them correctly, and special
tools are a requirement.
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Paul Tyler
Sent: Saturday, April 07, 2007 9:24 PM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Need help with a Revox A77 [?] in Chicago
That's a good suggestion.
David Lennick <[log in to unmask]> wrote: Have you tried recording
new material on this machine? See if you get the same effect on playback
(assuming you have tape on which to record..maybe a blank spot at the
end of one of your reels).
Scott Phillips wrote:
> This is part of the mechanical alignment of the heads, and can easily
> produce the symptom you describe. It refers to the 'tilt' of the
> heads, left to right so to speak, of the heads as you face them. That
> is, as you face them the heads are supposed to have their 'gaps'
> perpendicular to the direction of tape travel. This is normally set
> with a MRL or STL alignment test tape with a phase meter or more
> properly (IMHO) with a o'scope. For 'special' reasons it can me
> deliberately misaligned to match a tape made on a misaligned machine.
> I'm likely not explaining this well.... As is common with someone who
> has done it for so long... :>)
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]] On Behalf Of Paul Tyler
> Sent: Saturday, April 07, 2007 3:28 PM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] Need help with a Revox A77 [?] in Chicago
> Ah, there's another word of which I was ignorant. Is the azimuth
> related to the alignment? Could that be why one of the channels is
> way muddier than the other?
> phillip holmes wrote: Paul, Could be the playback head's azimuth was
> mis-adjusted (?).
> Paul Tyler wrote:
>> I'm hoping someone can help an electronic ignoramus. Here's the
> story. I have a hundred and fifty open reel tapes I recorded twenty
> five years ago that I've been trying to digitize. Most are field
> recordings I made on a Nagra on loan from the American Folklife Center
> or on a Revox B77 (I'm unsure of the exact model number) owned by a
> then brand new public radio station in Fort Wayne. The restof the
> tapes are the 26 one-hour radio shows I produced using my field
> recordings. After that gig ran it's course, I was left with the tapes
> and no machine. The original field recordings are in the Archives of
> Traditional Music at Indiana University, and what I have are earliest
> copies dubbed on the ATM's Ampex decks.
>> Fast forward twenty years and I bought a Revox A77 on eBay and
> dubbing my field tapes in my spare time. Somewhere along the way my
> preschool daughter filched a light bulb out the Revox--I don't know
> what you call it but it was for a light activated shutoff. I took the
> Revox to 20th Century Stereo on the north side. The elderly
> European-accented proprietor ended doing $300 worth of repairs and
> adjustments. This was two years ago, and I'm just now getting back to
dubbing my tapes.
>> But they don't sound the same. I don't have the technical vocabulary
> to describe the sound difference. The clarity is gone. It sounds
> like my recordings have gone through some sort of filter that
> distances the sound. Another description:
>> the loss of clarity sounds like what happens when you dub cassettes
> cheap portable decks from 1980.
>> Can anybody offer any help? Like what kind of words I should use if
> I take it back to the old German guy. Or do you know any other good
> repairman (or woman) in the Chicago area I could consult.
>> Thank you
>> Paul Tyler