Because the tape is wound oxide out and you're trying to record through the backing? Just a guess... Because it's very thinly coated instrumentation or logging tape? Just another guess which I believe less than the first one... Cheers, Richard On 2011-03-03 8:49 PM, Dan Nelson wrote: > I found several dozen reels of 1/2 inch black oxide 1.5 mil tape in my storage shed from at least 20/30 years ago. > They are 10" pancakes with cardboard seperators with scotch printed on the master carton of 12 but no type number where the paste on sticker was is missing. > On my Ampex 440 with "0" in i get like -20/30 out. I tried re-biasing and altering the bias has no effect on the output level.... > Any one have a clue why tape would act this way if stored for 20 years bulk ??? > many thanks > dnelson > -- Richard L. Hess email: [log in to unmask] Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX http://www.richardhess.com/tape/contact.htm Quality tape transfers -- even from hard-to-play tapes.