Reply-to: Association for Recorded Sound Discussion List <ARSCLIST@xxxxxxx>
At 03:02 PM 2008-04-19, carlstephen koto wrote:
Thanks Richard, that's been my experience as well. I have a number of
old acetate tapes and while I've found a good deal of cupping and
brittleness, they seem to have very even high frequencies.
Of course, taming the cupping can be a chore and if there is any
added spacing that, as you know, will affect the high frequencies.
An aside, I ran the calcs this morning for spacing loss and found
that if the entire back coating of a typical tape (I used the numbers
for 3M250 or 80 micro-inches) laminates itself to the face of the
oxide coating, the 15 kHz spacing loss is about 4 dB. I don't think
that's worth the risk of losing more by trying to clean it off.
I've had that type of lamination happen on tapes I should have baked
first...but this was more of a theoretical exercise as I was looking
at the relative thicknesses last night of tape components. For 3M 250
it's 80 microinches for the back coat, 680 microinches for the oxide
coat and 1300 microinches (1.3 mils) for the base film for an overall
thickness of 2060 microinches of 2.06 mils.
Cheers,
Richard
Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.