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Author Topic: tape squealing, not backcoated tape...  (Read 7182 times)

Offline Gkar

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tape squealing, not backcoated tape...
« on: November 01, 2010, 04:36:19 PM »
We all have heard of squealing tapes, particularly of the backcoated variety, however, I just pulled another reel of because of squealing, Dolby copy on London, Ampex manufactured, this is the second of this type of tape, a black colored tape, that seems to squeal for no reason, did it on side 2 about half way in, both tapes the same way (half way in side 2), there is no residue on the heads/path, what is causing this?  I had a similar problem with RCA Living Stereo tapes years ago, got rid of them, ones I have purchased recently have not had that problem, although the dreaded "edge ripple" comes up quite frequently...  any ideas?
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline jcmusic

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Re: tape squealing, not backcoated tape...
« Reply #1 on: November 01, 2010, 05:55:57 PM »
We all have heard of squealing tapes, particularly of the backcoated variety, however, I just pulled another reel of because of squealing, Dolby copy on London, Ampex manufactured, this is the second of this type of tape, a black colored tape, that seems to squeal for no reason, did it on side 2 about half way in, both tapes the same way (half way in side 2), there is no residue on the heads/path, what is causing this?  I had a similar problem with RCA Living Stereo tapes years ago, got rid of them, ones I have purchased recently have not had that problem, although the dreaded "edge ripple" comes up quite frequently...  any ideas?

Check your pinch roller carefully, Maybe even try cleaning it.

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Offline ironbut

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Re: tape squealing, not backcoated tape...
« Reply #2 on: November 01, 2010, 06:04:59 PM »
It's better to think about the squealing as a symptom. It's the result of a "stick/slip" between the tape and stationary guides/heads.
So, anything that can make a tape surface sticky can cause squealing (just like rosin isn't the only thing that will make a violin bow sing). I've had tapes that squealed which were made before the "sticky shed" problems which and I believe that something was spilled on them (blended scotch whiskey?).
Also, tapes don't have to be backcoated to contain the binder that led to sticky shed syndrome. It's just that the introduction of backcoated Ampex tapes was at the same time as their change to the bad binders that led to this problem. Any other tapes that they produced with this binder formulation has just as good a chance of developing sticky shed as the backcoated ones.
It would seem that tape stock that was already in production never had it's binder formulation changed but tapes that were introduced during that period included that binder in the formulation.
I'm not sure what the number is but some of the Barclay-Crockers that were recorded on a grayish brown tape also seem to suffer from squealing but I've never baked one to see if it's true sticky shed. I believe it is though. This tape isn't backcoated (it's only been about 5 out of 250 so it's not that much of an issue).
I've never had a squealing RCA tape and yours is the first time I've heard of it. Were you the original owner?
I have had a number of London/Phillips backcoated tapes that have squealed (Ampex production).
steve koto
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Offline dollysowner

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Re: tape squealing, not backcoated tape...
« Reply #3 on: November 02, 2010, 02:46:59 PM »
I ran into the squealing problem with a Dolby Decca recording of The Mikado (duplicated by Ampex), and with one Barclay Crocker copy of Gottschalk music for two pianos.  The tape used on the Decca/London recording was black (like Scotch 202); the B/C was the standard brownish oxide which Ironbut mentioned.  The tapes were not backcoated.  In each case, baking made absolutely no difference.  I tried the tapes on two different machines-a Revox A77 Mk IV and an Otari MX5050B-II.  Both machines were squeaky clean.  I tried applying LAST tape treatment to the heads and guides with no effect. 

This is not a sticky-shed problem, because the tape doesn't shed-it just squeals after about ten minutes, and baking makes no difference.  My guess is that the lubricant in the tape is simply dried out.  I don't think there is anything that can be done.  Fortunately, I've found it to be a very rare occurrence.

Offline ironbut

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Re: tape squealing, not backcoated tape...
« Reply #4 on: November 02, 2010, 03:30:29 PM »
Hey dollysowner, (btw, we use our real names on this forum which can be added to your signature in the user control panel)

I agree, there are some tapes that squeal that have nothing to do with binder hydrolysis. They are rare enough that I just segregate them in my collection in hopes that someday I'll stumble across a cure for them. I've tried lightly cleaning and lubricating a few with no success. I'm glad to hear that you've tried baking them so I can skip over that experiment. Personally, not a big deal.
steve koto
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Offline Gkar

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Re: tape squealing, not backcoated tape...
« Reply #5 on: November 02, 2010, 08:33:19 PM »
Dollysowner. you are right on point, these are London recordings, black tape, Dolby encoded, NO SSS!  they leave nothing on any rollers, guides or heads, and in both instances, the screaming started on side 2, after which I cleaned the tape path, within minutes the squealing started up again no matter which of my 3 machines I used, too bad as both were very good sounding recordings, and I don't think that these particular recordings are or were available in any other tape format, although I hope I am wrong.  Also, I have other Londons with similar provenance (dolby, black tape) that have not shown any signs of squealing, so I am not sure what is going on hear (hehe).  Of course, these other Londons may develop the same problem, I'll just have to see...

Steve, no, I was not the original owner of the LS tapes, these were bought mostly en mass at a second-hand record store in Balt.  I would say about 40% had the dreaded squeal, they were my first introduction to tape squeal.  Too bad, I have found that many of the LS recordings are really good, just got a killer today, Also Sprach Reiner/CSO 1962 version.  I have found that the LS tapes are prone to edge ripple and just plain bad sound on occasion, I don't buy any tapes I can't return because of this, I find about 25% of tapes are bad with various ailments, even BC's.  Some sellers on ebay are good about returns, some others, well, not sure but ddtsomething something on ebay only sells bad tapes with no returns...
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline Gkar

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Re: tape squealing, not backcoated tape...
« Reply #6 on: January 07, 2011, 04:26:01 PM »
well, the dreaded squeal happened again!  And once again, it is a black tape, London recording/ampex duplicated Dolby-encoded, the squeal seems to be occurring around the erase head on both of my machines (5050 and MTR-10).  Beautiful recording, no use to me now...  while I have a few of the same type of tapes that do not squeal, I would recommend staying away from any of the London/Phillips - ampex mastered black tapes, looks to be trouble.  Many are Dolby recordings, and the sound is very good, '70s recordings, but there is something amiss with the tape...
"Music possesses far richer means of expression, and it is a more subtle medium in which to translate the thousand shifting moments in the mood of a soul." - Tchaikovsky

Offline ironbut

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Re: tape squealing, not backcoated tape...
« Reply #7 on: January 07, 2011, 05:17:23 PM »
Yeah. I tried buying several of the London/Phillips Ampex recordings and gave up on the latter production because of squealing and QC problems.
A few years back I bought several copies of Solti/CSO Symphony Fantastique and even though they didn't squeal, the azimuth and/or track placement was so far off that I gave up.
Major bummer!
steve koto
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