Which calibration tape?

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lespaul68

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Hello Everyone, Which would be the correct MRL calibration tape to use with a Teac 80-8 1/2" 8 channel 15 ips reel to reel deck. When I bought the machine, it included a Teac YTT 1144 calibration tape, but the tape is completely shot. I have read from several sources that 250 nWb/m is, (like the original YTT 1144), for old tape formulations like the original Ampex 456. RMGI SM911 does not sound like 456 when the machine is calibrated to 250 nWb/m, it sounds like mud. Some say the machine should be calibrated to 320 nWb/m to make use of the newer tape formulations, like SM911. I really don't have much experience with this, and would really appreciate some good advice. I can't afford to make a $200 plus mistake with this. Thanks in advance.
 
TEAC released updated versions of the YTT-1144. They came out after the tape problems were fixed as far as I know, but they're hard to find. There's a YTT-1144SP and a YTT-1144-2. I learned later that the YTT-1144-2 is not full track, but was made specifically for 8-track for precise track alignment at time of machine manufacture. I think the YTT-1144SP is full-track and includes the 3kHz tone for set tape speed at 15 ips. I think I have that right, but it's been a while since I looked at them and Tascam tech support either wants to keep them top secret or the people working there now don't have much info on them.

If you want to go to the trouble you can bake your old YTT-1144 and it will be pretty close. If you want to buy a new MRL equivalent the model number is 31J229 for 250 nWb/m. I have that one, the older YTT-1144 and the last one TEAC made, YTT-1144-2.

I was able to bake the older YTT-1144 and even though it has sticky shed, after baking it agreed perfectly with the levels on the MRL 31J229. Pretty amazing how precise these calibration people like Jim McKnight can get these tapes even years apart in production.

SM911 will not sound like mud because of flux level, but more likely a bias issue or head going bad on that machine. Was the machine working ok before with 456? Does it still sound ok with 456? It could be it was biased for a +9 tape like SM900, GP9 or 499. In that case it's too much bias for SM911 or 456 and will dull the high frequencies.

You can always use 320 nWb/m with 456 and SM911 and always have been able to, but it won't help this problem. Also the crosstalk on the 80-8 wasn't nearly as good as the heads designed for the later 38, 48, TSR-8, etc. And if you have the dbx unit for it you'll want to keep it at 250 nWb/m anyway. Higher flux levels won't do you any good with dbx.
 
I thought and heard from off the tapes that they were all recorded full track to (IEC or NAB specifications) so the tapes should not be recorded with any track on them as that would be asking for trouble. The tapes I have and those I have used over the years were full track.
You may know me from another Forum as well.
 
skywaveTDR said:
I thought and heard from off the tapes that they were all recorded full track to (IEC or NAB specifications) so the tapes should not be recorded with any track on them as that would be asking for trouble. The tapes I have and those I have used over the years were full track.
You may know me from another Forum as well.
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Nearly all calibration tapes are made full-track. You’ll be hard pressed to find any that aren’t, except it was more common to see tapes made with two distinct tracks for half-track. TEAC and STL made them.

TEAC had a later version of the calibration tape for the ½” 8-track head (which by the way they invented). All I was able to assertain is that it was for initial fine head height setup in the factory. Towards the end when Tascam/Teac was outsourcing more factory service some of these tapes escaped and eventually got circulated. I found this out the hard way to my chagrin after buying a few from the University of Illinois School of Music. I assumed they would be full-track, until someone tried to use one to setup an MSR-16. Tascam service hardly knew anything about them when I called. The first guy I talked to said he’d never even seen the YTT-1144SP or the YTT-1144-2, but his supervisor knew a bit more.

It didn’t make a lot of sense to me either at first, but I’ve heard no other explanation. One thing to keep in mind is that as stated earlier, Tascam invented the ½” 8-track open reel format, they were the only company designing and manufacturing their own heads, and tolerances were quite tight for the late model heads... 38 version and on. Overall their machines performed better than Fostex and Otari in gap scatter and crosstalk because of good R&D focused on doing just that. So yes, I can see them getting away with making a calibration tape recorded on 8 individual tracks for a specific purpose. You might want to have a full-track version as well, but no one from Tascam has been able to tell me much about it. All I know is that it works perfectly with my TSR-8. YMMV

It’s all academic though, because I’m one of the few people on earth that owns one as far as I know. I never see them for sale anymore, but I do see them referred to in old Tascam manuals and brochures, so I know there must be more out there.

Fostex made a basic calibration tape as well that would work with the 80-8, but to make life simple the best thing to do these days is buy an MRL 31J229 from Jim McKnight and be done with it.

Who are you on another forum? I'm me on every forum... Beck.
 
skywaveTDR said:
I thought and heard from off the tapes that they were all recorded full track to (IEC or NAB specifications) so the tapes should not be recorded with any track on them as that would be asking for trouble. The tapes I have and those I have used over the years were full track.
You may know me from another Forum as well.
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Yes Skywave, I'm the guy from the other forum. I'm sorta stuck right now...need to save up some $ for the calibration tape. I noticed the the headstack from another 80-8 (parts unit, bought it 5 years ago) is of a different design. These rec/repro heads have a radically raised tape contact area (head cores), and relief slots!! They carry the part number: 50640812. The other (good machine?) heads carry the number: 50640811. Also, the access holes on the sides of the machine (visible when the side panels are removed) are round and sharp, making it uncomfortable to pick up the unit. Whereas, the access holes on the parts machine are square, and have a "built in" handle, making it a breeze to lift. So, apparently the "good?" machine is an older one, and Teac must have made improvements in this machine over the years 1976-1982?. Have you ever noticed those differences yourself? I want you to realize that I am not just full of hot air...I am serious about fixing the problems with the machine, and genuinely appreciate your input. I spent alot of bucks on this unit about 15 years ago...head re-lapping, a pile of sm911 tapes..plus the cost...$450.00 of the machine. Did it on a very tight budget...you know, wife, kids, college for kids..etc...when the results of the cash outlay for the machine were much less than expected, I shelved the whole mess, and went "cringe!", "gulp" with digital. Picked up a Layla20 8 in 10 out interface for more big bucks. Anyway...I do not like digital as a primary recording device. I noticed (as I assume you have) when audio, particularly bass guitar or drums, is recorded primarily in the digital realm, the results are sterile, and lifeless...it takes so much editing (compress, eq, multiple times) to get it to sound marginally decent, that the noise level is now quite high, even higher than an analog reel to reel. When the primary recording device is an analog device, and the tracks are "dumped" to digital, it is a different story. The trade offs are less, as some of the analog "fullness" is preserved. Digital is presently a "crude" method of reproducing audio. I believe it is still in its infancy. Many improvements will be made.
 
lespaul68 said:
Anyway...I do not like digital as a primary recording device. I noticed (as I assume you have) when audio, particularly bass guitar or drums, is recorded primarily in the digital realm, the results are sterile, and lifeless...it takes so much editing (compress, eq, multiple times) to get it to sound marginally decent, that the noise level is now quite high, even higher than an analog reel to reel. When the primary recording device is an analog device, and the tracks are "dumped" to digital, it is a different story. The trade offs are less, as some of the analog "fullness" is preserved. Digital is presently a "crude" method of reproducing audio. I believe it is still in its infancy. Many improvements will be made.
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I thought this thread was just about finding a suitable calibration tape but for some reason it has drifted off into a strong condemnation of digital recording - such a rarity on this analog forum...

You asserted that "digital is presently a crude method of reproducing audio". Perhaps you should assert that in an appropriate digital recording forum, which isnt this forum.

BTW I love analog tape and digital but not for the same reasons.

Cheers Tim
 
Tim Gillett said:
I thought this thread was just about finding a suitable calibration tape but for some reason it has drifted off into a strong condemnation of digital recording - such a rarity on this analog forum...

You asserted that "digital is presently a crude method of reproducing audio". Perhaps you should assert that in an appropriate digital recording forum, which isnt this forum.

BTW I love analog tape and digital but not for the same reasons.

Cheers Tim
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Thank You Tim for you "digital" input
 
I have used the 250 nwb/m for my MSR-24, MS-16 and TSR-8's. I use RMGI 911 and I think they sound great. I dont remember 456 ever sounding this good back in the 90's.

VP
 
And keep in mind that you can use any level calibration tape to setup any operating level (i.e. you can use a 250nWb/m tape to set your machine up at 320nWb/m). You don't have to have a cal tape for each operating standard.

If you have a 250nWb/m (+3 over 185nWb/m) tape and you want to set the machine up for 320nWb/m (+5 over 185nWb/m), then you would just reference -2VU on your meters during the level setting steps of the calibration procedure (after you calibrate your meters of course :)).
 
Thank you everyone for your advice. I remember somewhere I read that it was just a matter of compensating your levels, with that in mind, you can use any calibration tape. By the way..does anyone here want to sell their old calibration tape? Mine is total trash.
 
lespaul68 said:
Thank you everyone for your advice. I remember somewhere I read that it was just a matter of compensating your levels, with that in mind, you can use any calibration tape. By the way..does anyone here want to sell their old calibration tape? Mine is total trash.
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I have 4 TSR-8's. 2 have been recently cailbrated. I think it is possible to make a fairly accurate test tape from one machine to the other. I would be willing to try. The only problem is the 2 machines are in seprate buildings on my property. Any thoughts?

VP
 
This is true. In one sense, playing back such a tape on another 8 track machine will be easier to interpret because there wont be any "fringing effect' to compensate for, which is the case when playing a standard calibration tape made on a full track machine.
The only thing you would need to be careful of is that on the machine to be checked the head is vertically aligned.

For many years I've saved wear and tear on my expensive test tapes by carefully making a secondary test tape from a machine known to be well aligned. I use that secondary tape confident that even if I damage it, I can go back and make another.

Note that strictly speaking, the tape you make is only accurate for the actual frequencies that are contained on the original test tape, and to be quite accurate you should copy any small deviations in average level for each of those frequencies on to the tape you are making. This way you are trusting the actual calibration tape as your reference rather than making assumptions that any slight devations are the fault of the original calibration tape rather than your machine. The deviations are more likely to be in your own machine's idiosyncracies than inaccuracies in reputable calibration tapes which are made to quite a high degree of accuracy.

The other caveat is that it's still easy to ruin the best calibration tape with careless use such as running it on a machine, even once, with a magnetised tape path. It doesnt matter how much money you spent on it. It's easy to stuff it up if you're at all that way inclined! Of course high frequencies are the most easily damaged and they always head southwards, not northwards.

Of course it gets a bit more tricky if you are trusting that someone else's alignment of your machine was done accurately. And no alignment is ever perfectly accurate. It's always within plus or minus something..

Tim
 
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Tim Gillett said:
This is true. In one sense, playing back such a tape on another 8 track machine will be easier to interpret because there wont be any "fringing effect' to compensate for, which is the case when playing a standard calibration tape made on a full track machine.
The only thing you would need to be careful of is that on the machine to be checked the head is vertically aligned.

For many years I've saved wear and tear on my expensive test tapes by carefully making a secondary test tape from a machine known to be well aligned. I use that secondary tape confident that even if I damage it, I can go back and make another.

Of course it gets a bit more tricky if you are trusting that someone else's alignment of your machine was done accurately.

Tim
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My MRL Test Tape had "Fringing Compensation". My machines are very accurately aligned, I am very methodical and stringent with tolerances. Tascam will spec +/- 3 db, but I will insist on 0db. It takes me a while to get it done this way.

VP
 
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I sent you a private message, Victory Pete..let me know if you did or didn't receive it.
Victory Pete said:
I have 4 TSR-8's. 2 have been recently cailbrated. I think it is possible to make a fairly accurate test tape from one machine to the other. I would be willing to try. The only problem is the 2 machines are in seprate buildings on my property. Any thoughts?

VP
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You could pick up one of the TSR-8 decks and bring it to where the other one is. :)

Just saying.....
 
miroslav said:
You could pick up one of the TSR-8 decks and bring it to where the other one is. :)

Just saying.....
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Yes well, laziness (and a flight of stairs) forced me to come up with another solution! I have a recently calibrated MS-16 with the same type test tape. I could play back tracks 1-4 and 13-16 to reform the "Fringing Compensation" symmetry. I think that would be just as accurate.

VP
 
miroslav said:
You could pick up one of the TSR-8 decks and bring it to where the other one is. :)

Just saying.....
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I was going to suggest making use of a Star Trek replicator...but I guess your idea would work too. :mad:

Cheers! :)
 
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