Tape Project Forum

General Category => Prerecorded Tapes => Topic started by: astrotoy on April 02, 2008, 12:29:47 PM

Title: Tape Colors and Types
Post by: astrotoy on April 02, 2008, 12:29:47 PM
As I go through my prerecorded tape collection, finding new treaswures and really better sound from my new Bottlehead 1506 with REPRO, I notice that there seem to be three main kinds of tape stock used. My tapes are almost all classical, London for the most part. The recent tapes which are generally in the best condition are close to black in color. About half of these are dolby B encoded.  The oldest tapes, where I often find a weak left channel or some drop outs (typically on the left channel) are a light brown/tan. They also have generally more tape hiss. The intermediate age tapes are more like the oldest tapes in color, but a bit darker. They are typically in better condition.   Just about all of the tapes have AMPEX on the reels. All the tapes seem to be 1 mil in thickness, that is 1800 feet or 45 min fit onto a 7 in reel. Occasionally I will have a tape reel that is very full and over 45 min in length. I think the TP tapes are thicker, perhaps 1.5 mil, with 2400 feet max on a 10.5 in reel.

Any comments from the experts out there?

Thanks, Larry
Title: Re: Tape Colors and Types
Post by: ironbut on April 02, 2008, 05:43:25 PM
Hi Larry, enjoying your set up? The really old tapes (many of the 2 tracks for sure ) have an acetate base. The color of the oxide will actually vary with the same manufacturer over time but the material that it's on is pretty significant. The easy way to tell if a tape is acetate is to hold the reel up to a light. If you look through the windage holes, with an acetate tape, you can see some light but with all other bases, you can't ( there are a few exceptions). Acetate is actually the same stock that early film was made on and the early tape manufacturers (including Ampex) used the same stock to make recording tape. The problem with acetate is that it doesn't age well. It has a tendency to become brittle, much to the dismay of many silent film buffs. I just bought an old Verve, Oscar Peterson Trio "A Jazz Portrait of Frank Sinatra". It was made by Ampex and is on acetate. The sonics are excellent, in between the splices that is. There must be over 15 splices that are pretty well done and I've added tons of leader to both ends, but I broke the tape 2 times just trying to give it a first listen. I have a number of acetate tapes and going on sonics alone, you'd think that it would be the backing of choice. I think that it's more like a timing thing. I think the early reel to reel user was just like us. That's why you see so many demonstration tapes and "sonic spectaculars" with trains whizzing past and the poor little Bikini islands getting blown to smithereens over and over. They were more like statement products than what every kid was hoping to see under the xmas tree.
 I have a feeling that the different record labels had a choice of the tape that was used (or made the choice with their wallets) because some tapes I have of the same time period, and manufactured by Ampex at the same plant, were recorded on different formulas of tape.
I don't know if you've already traveled down the Sticky Shed Syndrome path but that is another very important tape consideration. In the mid 70's, because of the oil embargo (remember that wonderful little panic) Ampex was forced to change the binder that glues the oxide to it's backing. They made a real bad choice with their 456 tape (as did a few other manufacturers) so, depending on the record company, some of the tapes of this era may have SSS.  For more on that, check out Richard Hess's site that's linked in my sticky at the top of the General forum. Agfa had a similar problem when they decided to lower the pollution from their plants in Germany.
So the tape that Ampex spooled for the different recording companies could have changed in mid issue with some releases. It could be because of the record company, or it could be because of Ampex.
Lots of the commercial issues were made on 1 mil or less. That's why I avoid the twofers.
Title: Re: Tape Colors and Types
Post by: docb on April 03, 2008, 10:00:40 AM
Hi Larry,

If you are getting weak signal or drop outs on only the left channel and only on certain tapes it could be something that is correctable by a slight tweaking the alignment of the quarter track playback head. If you don't want to take that on yourself the guys at the studio can tweak it up for you using the tape in question and a known good quarter track tape, to find the best balance between both. 
Title: Re: Tape Colors and Types
Post by: astrotoy on April 03, 2008, 11:33:23 AM
Steve and Doc, thanks for the information. I'll contact Doc off line on the head allignment. Larry
Title: Re: Tape Colors and Types
Post by: ironbut on April 03, 2008, 06:13:51 PM
Larry, Doc probably already told you but, the left channel with 1/4 track, is always played with the outermost portion of the playback head. That's also the hardest bit of the playback head (on an RS1500) to get at because of the headshield and the angle. If you've been playing a lot of old tapes, you could very well have a clump of crap that has eluded your head cleaning (sometimes you can get enough build up from just a couple of tapes).Try cleaning your playback head taking special care to get inside of the outermost portion of the shield. If your using Q tips, you have to really get in there because of the curve of the cotton.
Another thing to bear in mind,.. the left channel is the outside of the tape on both sides. And because of it's inherent exposure, it will almost always be what gets damaged whether is from heat, moisture, magnetic fields, mold, alligator skin underwear, or your cousin Anne. The right channel is safely hidden inside the tape wrap in either direction.
Title: Re: Tape Colors and Types
Post by: docb on April 03, 2008, 06:36:33 PM
Yeah, duh, thanks Steve. I shoulda thunk to say clean the heads first and call me in the morning...

Whilst I'm here - will be trying a new tape guide on the 1500 next week - needle bearing with ceramic flanges, like an ATR100.