I find most tapes can be excellent, I have some old pre-recorded ones (acetate, you can see light through them sideways) which probably are as good as they were 40 years back. How long such tapes will last...Hmmm. Anyone's guess, I'd think several hundreds plays if the tape transport treats the tape with even and constant tape tension - and add to that low tape tension. They say acetate gets brittle, with age, but I've never seen that. Sticky Shed Syndrome (SSS) I have seen; also instances where backcoated tapes have had the backcoating bleed to the edges and form clumps due to fast winding tension. Well sometimes Sh-t happens.
I also note that the Pioneer RT-909 as per factory spec, has tape tension set much higher (as I recall its over 30% to 40% higher) than most other high-end RTR's, so I would stay away from that set due to: faster head wear and high tension, if playing older acetate reels or very thin tapes like 1/2 mil. mylar are two of your uses for a machine.
The first thing I do with an older pre-recorded acetate reel, if it doesn't have leader tape (most don't), I put five to eight feet of paper or plastic leader on any reel I get. Such old tapes should really
never be played on a single motor consumer level machine. The tape tension and use of pressure pads can damage or ruin the tape by stretching and/or abrasing the oxide right off the backing.
Also worn heads which have a groove cut in the surface can cause microscopic edge abrasions that ruin the edges of the tape and cause wow and flutter to be higher, and can lead to breaks and loss of oxide. Lastly a clean tape path and clean heads are also necessary for the tape to remain intact and to retain proper channel balance. Gummy tape residue present on the guides will increase friction, which can lead to stretching, breakage, and cupping damage.
I think the best RTR players are those that feature dual-capstan transports, where both capstans are large in diameter, and rotate at slower speeds, and are located to the left and right of the tape path and all the heads. On such transports, tape handling seems much better within the tape path, when compared to single capstan, 3 motor sets, where a centrally located capstan, or offset (after the heads) capstan is present. For me, only a few sets are like this and the list includes the servo-controlled motor, belt drive dual-capstan Akai's: The PRO-1000, GX-400D, GX-400D-PRO, GX-400D-ss, and GX-650D. I own four of those five sets. And also a couple of Sony's, the TC-558 or TC-756/758 in the 10.5 inch reel versions.
Next best would be centrally located single capstans, within an auto- reversing mirror image head lineup, as seen in the Akai GX-636, GX-635D, and Akai GX-266 MKII, GX-267D, GX-266D, Kenwood KW-8077; and Technics RS-1500, RS-1700, and the rarely seen RS-1800 series.
Slightly less best would be the offset capstan type, which can still treat tape well, if relay or logic is imposed with delays as seen in the Akai GX-630D, GX-625, GX-620, GX-255, and the Sansui SD-7000, and Tandberg 20A, 10XD, and 9000 series; Revox B-77, A-77, etc.
Steven L. Bender, Designer of Vintage Audio Equipment
Considering the forum you posted this in, I guess your talking about prerecorded tape. Most of them has lost just a touch of extreme high frequency. At least, that's the general thought. I've had incredible luck with the tapes I've bought. If it sounded good in the first place, it sounds good now. Some will knock your socks off! I think most of us will agree that the way that the tape was treated by it's former owner/owners has way more to do with how well they can be enjoyed now. If the tape itself is pictured in the ad ( I almost never even look at ones that don't have a picture of at least the box) look closely to see if the tape wrap is even and the end is held down. Look at the box condition. Even if you could care less personally, it shows how carefully the owner stored and handled the tape itself. I seriously doubt that most of the major sellers of r2r tapes really listen to all of them. So, having a good return policy is important. Finally, there was a shocking number of these tapes recorded. If you want an idea of this, check out Stellavox's post regarding his listings of 1/2 track r2r over on Yahoo's reel to reel group. He has invested a hugh amount of his own time to bring a fantastic service to us all.
