[QuadList] A Little More on Toluene

Thu Jan 21 18:52:57 CST 2010

I have received a couple comments since sending in my first note on the subject.  I appreciate all the info from you guys.

Long before SSS was in vogue as a problem, it was simply called "Rim Buildup", where after a while this gooey sticky binder material and it's oxide would collect on the rim around the headwheel.  It made an audible buzz, louder than the normal head contact.  It would also cause a visible scoring on the tape and the tape would become useless. It wasn't untill later years that problem of SSS showed up on the guides, audio stacks, etc.  This is perhaps because at CBS every operator was required to clean the whole deck, heads, guides and all with Freon before each playback and each recording.  While this may not have been the best agent to use the frequency of the cleaning may have prevented SSS back the early days, as well as the tape being fresh. They also provided tooth brushes to clean the heads, with freon. (Not My Idea)

Lets also not forget the scratches this stuff can cause along the tape path.  Not the kind of scratches which dig into the tape, but magnetic scratches caused by magnetic oxide packed around the audio stack, guides, etc. Depending on where this stuff exists, you may get away with a clean playback, but really scratch it on rewind.  So swabbing (Navy Term) the deck with a good solvent like Toluene or other solvent helps to improve quality.  I convinced CBS Archives to not rewind the tapes partly for this reason, not that they would need the tapes again, but also, after about 3/4 of rewind on a 90 minute reel the (AVR-1's) capstan MDA's would eat some of it's transistors.

"Park" (I hope that is how he is addressed) suggested that the binder is a polymer based stuff.  That may be, but I remember the old tapes (Ampex) used latex to some degree. At any rate Toluene will do a fine job of cleaning up the polymer based stuff also. This is the case at CBS Archives's AVR-1's.  Alcohol helps, but it is much harder to clean up the SSS with it.

Also, I forgot to mention that the problem with the Digibeta heads I encountered was after using the Sony cleaning tape, not only the way Sony wanted us to use it, but for much longer times. (Please don't tell anyone) and even putting my finger on the tape while it is running so as to burnish the heads more.  (If word gets out about this I will really be in trouble-hi).  After all this cleaning with the cleaning tape, alcohol, the heads were still dead.  Then I went a couple times around with Toluene and the heads came up good as new, and stayed that way.  This tells me that even though they were metal tapes they were still depositing something on the drum or heads which was keeping the tape away from the heads.  I have even had the identical problem with D-2's. I have also had the same luck on the 1100A's and 2000's.

I did notice that the problem with the DIgibeta heads seemed to go away to some extent after a year or two, so there may have been a problem with the tape.  I don't think Sony will never tell you that they had a problem, they will just listen to your problems, go back to the office and call Tokyo, then they will fix the problem, quietly. They also won't tell you exactly what is in the tape, binder or oxide.

I also remember there was a 2 inch "Cleaning Tape" made by Ampex.  It would also burnish the heads if needed.  It was green.  If anyone has one, save it, it is a relic.

I will also take the "Fifth" as to what brand of tapes were involved with each problem. (Craft Club).

If any of you folks are having any of the problems, give it a try and let me and the rest of the list know if it helps.

I also noticed on"Park's" website the videos of the job he did on his 1200. I found it very interesting and well done.  I will reflect on my meager experience in the refurbishing of quad machines later.  I remember that CBS had only one 1200 (VT-G) and it was about the best and most reliable machine in the place, probably because it had the fewest CBS modifications and was used primarily for transfers to ACR. I don't know what happened to it, probably went in the same dumpster with the ACR's.

Speaking of modifications, one that I did was to eliminate the capstan discriminator.  The machines lock up a couple seconds sooner without the disc.,  just the phase comp.  I put this into machines all over the area and the owners were pleased, although I didn't tell them that I had made a mod to their machine. If anyone really, really wants it, I will dig out a schematic and try to remember how I did it, it only took a few minutes with a soldering iron and a razor blade.  Also all the "REF Discriminators" were eliminated as we had fixed plant sync to all machines and wasn't necessary.  This wasn't my mod, I think Ampex recommended it.

One more thing, has anyone heard from "Mr. Ampex Video Tape" Mr. Lou Bitton??  We were very good friends. The last I heard from him he bought some property in Placerville, Cal.  It contained an abandoned gold mine.  He was also having some medical problems.  I can't seem to raise him on the land line at all.

Regards to all,

George Keller

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