Re: [ARSCLIST] Ampex 456 - tip of the iceberg...chemistry

["Scott D. Smith" <lists@xxxxxxxxxxxxxxxx>]

Scott P.,

Your observations regarding 468 and 469 are similar to the experiences I 
had with some batches of stock (in all widths) around the mid-to-late 
1980's. The stock we received prior to this time period seemed to be 
fine, and the tapes I still have on the shelf which date from about 1979 
to 1985 all play fine, as do tapes from the early and mid 1990's.

It would appear that sometime during the 1980's something must have 
changed in the binder formulation for this particular stock, although I 
have never been able to get anyone from BASF/AGFA to own up to the 
problem. It would be great if we could nail down the time frame and 
batch numbers that were affected, so as to be able to put together a 
database of possible problem tapes to look out for. Unfortunately, with 
the demise of AGFA/BASF, I have lost contact with the few people I had 
correspondance with over the years. Perhaps someone on this list has 
contacts in Germany who might be able to track down some of the 
engineers. My contacts in the States have all told me that they have no 
personal contact information whatsoever.

As pointed out by Tommy Sjoberg, we have also encountered some problems 
with 469, which appears to have different issues, and nearly always 
requires a longer baking time than 468. I have never had the substance 
analyzed, but it is unlike any similar bleeding we have encountered on 
other formulations from the usual suspects. This might be a job for 
Peter at Spec's Brothers.

Scott D. Smith

Chicago Audio Works, Inc.



Scott Phillips wrote:

> I had this experience with it for several years in the 80's here in the states. It was all 2" and 1/2". It was at a major studio, and it had to be about several hundred rolls. We aligned and used whatever brand tape the clients wanted to use, and for a while it was largely 468 because of the character of the noise floor it had and a very sweet sound. It got to the point where you couldn't make it through a 3 week recording session with the stuff without it starting to shed like crazy, then get sticky-gummy. If you were lucky, you caught it in time and did a transfer of the recording so you could finish the sessions. Finally we simply wouldn't offer it to the clients at all without a signed disclaimer from them.  While we sometimes had a batch or so of any brand that had problems, nothing on this scale happened with them. It wasn't storage conditions at our end, we used a climate controlled vault for all tape, and the tape was shipped directly to us from Agfa. Interestingly, 469 didn't do that at all. Bear in mind that all this tape was brand new at the time.....
>
>
>
> -----Original Message-----
> From: Association for Recorded Sound Discussion List [mailto:ARSCLIST@xxxxxxx] On Behalf Of Tommy Sjöberg
> Sent: Thursday, June 22, 2006 4:56 PM
> To: ARSCLIST@xxxxxxxxxxxxxxxx
> Subject: Re: [ARSCLIST] Ampex 456 - tip of the iceberg...chemistry
>
> When I was working on a digitizing project a few years ago we had lots of Agfa PEM468, and all of them ran without problems. Maybe there was a small batch of 468's that we never encountered...
>
> Anyway, that 468 would be troublesome is surprising to me (I could be wrong, of course). PEM469, on the other hand, nearly always had problems. Unlike the 468 it didn't have the number printed on the backcoat in blue lettering. Also, unlike both Ampex and Scotch, its sticky substance was an almost clear yellow, and usually took longer to cure in the convection oven. It usually played fine in the end, however.
>
> Tommy Sjoberg
> Center for Swedish Folk Music and Jazz Research Stockholm, Sweden
>
>
>
>  
>
> > That was my experience with 468 as well... Although I thought it 
> > sounded very good.
> >
> > No free lunch....
> >
> > -----Original Message-----
> > From: Association for Recorded Sound Discussion List 
> > [mailto:ARSCLIST@xxxxxxx] On Behalf Of Karl Miller
> > Sent: Tuesday, June 20, 2006 9:53 AM
> > To: ARSCLIST@xxxxxxxxxxxxxxxx
> > Subject: Re: [ARSCLIST] Ampex 456 - tip of the iceberg...chemistry
> >
> > On Sat, 17 Jun 2006, Steven Smolian wrote:
> >
> >    
> >
> > > Was Agfa 468 polyester?
> > >      
> > I believe it was. My experience with it was miserable. I had never seen 
> > tape ooze before. It was a mess within a few years.
> >
> > Karl
> >    
>
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