New Audio Test Tapes as you know are quite expensive.   Buying a used Audio Test Tape is not highly recommended,  since you have no idea of the 'quality' of the Test Tape,  or if it's been 'repaired' by re-recording a area of the tape someone erased   (I've seen this done!),  or even if the tape will play back correctly.

A Test Tape that has been damaged is almost worthless - it no longer is an accurate reference.

I've seen used Test Tapes that have had severe edge damage,  meaning the upper and lower edges of the Test Tape would not reproduce correctly... if you used this to align your recorder, you'd be way off target.     But if you do buy a used audio Test Tape  - and there are good ones out there -  make sure the seller guarantees it and will refund your money if the tape does not playback correctly or shows any sign of damage or drop-outs.

But also realize this is asking a lot of the seller...   YOU the buyer can damage a good Test Tape by playing it back just once on magnetized heads or a machine that has transport problems!!!  So it would be possible for a Seller to sell you a perfectly good Test Tape and have the buyer damage it even if he or she played it back just once!

-------------------- Tips and Recomendations ------------------------

Make sure the Test Tape is a recent 'vintage' - made within the last 5 years - so you know it's on good quality audio tape!!   A Test Tape made with older audio tape can be 'sticky', have huge drop-outs, or not last for any length of time.

Test Tapes branded  'Ampex'  are generally very old  (they're at least more than 10 years old now)  and I do NOT recommend them.     Test Tapes branded  "STL"  are also very old and once again I do NOT recommend them.     Even the older  "MRL"  Test Tapes   (pre 1995)  are to be avoided in my opinion....   they could be made on the old 'sticky' tape which would render the Test Tape nearly unuseable.  

Any Test Tape made before 1995 should be suspect... most have the 'sticky tape syndrome'.

A "MRL" Test Tape made within the past 5 years IS what I'd recommend if you're going to buy a used Test Tape.

Make sure you know what type of standard you want your Test Tape to be:

NAB or IEC eq for 7 1/2 or 15 ips (all test tapes are 'AES" eq at 30ips)

Make sure you get a Test tape made to the 'Operating Level' you want to run your machine at  --  though you can align a machine to most any 'Operating Level' with just about any level test tape IF you know how to do so - it's not hard

Generally you would buy a Test Tape recorded at an 'Operating Level' of:

+3 level 250nW/m (I recommend +3 for all semi-pro machines and some older pro recorders, and especially for engineers who are just starting to record onto analog tape)

+6 level 355nW/m (I recomend +6 for Pro Machines - Studer, most Ampex, most MCI, Otari)

+9 level 500nW/m (not Recommended - you can align to this level using a +6 level Test Tape easily, and I'd recommend the +6 level Test Tape over the +9 level Test Tape)

old Test Tapes are likely recorded at an  'Operating Level"  of '0' level, which represents  "185 nono-webbers per meter" (nW/m)  THIS IS AN OLDER STANDARD LEVEL NOT IN GENERAL USE TODAY !!    I do NOT recomment buying a Test Tape recorded at this reference level    ('0' level 185nW/m)  unless you are using old consumer tape recorders or very old pro recorders...i.e.  an Ampex 300 or 350.

---------------------- How to test a used Test Tape ---------------------------

Note: You MUST have a tape recorder in good working condition, with good heads, fully cleaned and de-magged, without ANY transport problems and no known audio problems, and one that has recently been aligned for these tests to work!!!

Of course if you have access to a new audio Test Tape to compare the used one to, the testing is simple and swift.... if they match up (accounting for any overall level differences), the used Test Tape is fine, if some tracks show up different by more than 1db... it's bad or damaged.   If the high frequencies are stable on the new Test Tape, but 'wobble' on the used Test Tape, most likely the older used Test Tape is wearing out or has a problem.

One test you can do yourself even if you do not have access to another Test Tape to check a used Test Tape is to align your machine to it, then flip the tape over and play it back (it's now backwards)....   now the track 1 band is playing back on track 16. (if we have a 16 track machine)   ...but the level SHOULD be exactly the same on ALL tracks - the level on the entire width of the tape is the same in a good quality new or used Test Tape.   If you find that some tracks do not match up, especially the upper and lower tracks, then you may have tape damage or wear outs.   You especially need to do this check with the higher frequencies.   Again you MUST align your machine precisely, and your machine has to be in good condition. (I personally would not worry about small errors of say 1/2 db or so)

If you were to play back a Test Tape on heads that are magnetized you can wipe as much as 2 db of level at 10khz... and I've seen this done.   This is why you flip the Test Tape over - if say track 3 were magnetized for some reason when the previous owner played the tape on his or her machine (thus partially wiping high frequency tones on that track), you could still align your machine -- but not correctly -- since you'd make up the wipped off tone level by increasing the frequency EQ level in the reproduce alignment.   The previous owner might not even know the Test Tape is bad.

But if you align your deck, then flip the tape over, you'll see -   in the above example   - that the mis-aligned track (track 3) will play back the 10k tone 2 db hotter -   (since track 3 is now playing back a good area of the Test Tape),  while our track 14   (if we're using a 16 track recorder)   will play back the 10k tone 2 db lower (it is now playing back the damaged area of our Test Tape)....   if the tones do not match up very closely, the tape is most likey damaged!   -- again you must have a tape machine that is in good condition, with good heads, fully cleaned and demagged on which to do these kinds of tests on a used Test Tape.

Note that if you have a good Audio Tech in your area, they can come in and align your machine to their Test Tape  (which they should be replacing every 2 - 4 years themselves),  then make you a "Set-Up" tone tape on your machine that you can use to check and align your machine with.     Note that a 'real' Test Tape is recorded then entire width of the tape and thus you can use the same Test Tape to align a 2 inch 16 track or a 2 inch 24 track... while a 'Set-up" tape can only be used on the track-format it is made with.

Also note that if you have very worn heads, you'll likely NOT be able to align your machine up correctly...   especially if you have a large 'flat' area on the heads.

best regards to all you Analog Recording folks!     Hope this helped a little...

goreski-tech   - aligning and fixing professional tape recorders since 1976 !! http://www.AnalogRules.com