Good 'Semi-Pro' Half Track decks for High Output tape (+9 etc)

LUNE

LUNE

...a pieds joints
Hi,

So I've read a bit about peoples perspectives on running the +9 (or higher) range of tapes (Q 499 / SM-900 / ATR) with the 'semi-pro' format tape decks (1/2" 8-track, or 1/4" half track) and why its not always possible or advantageous.

What ARE the 'semi-pro' half-track decks that could take it as is or with minor modification?

quoting some post from EVM1024: "There is a mod (increase the bias coupling cap value from 100 pF to 180 pF) that will allow the MS-16 to bias properly." I presume this would work out for the 52 as well? what about the 42?

And the Otari 5050 series? (I don't know much of the differences between the ii, iii etc.)

I'm just trying to get an idea of what machines could be biased for the +9 tapes and would have a chance of holding up to the added strain of the thicker tape.

anyone have any experience with that?
 
I don't have any direct experience but will pass on this caution: Sometime in the 1970's, Dick Rosmini, author of TEAC/TASCAM's MultiTrack Primer, among other things, asked the TEAC techs to optimize his 3340 for Ampex 456 @ +6. The machine had enough suds to be biased & eq'd for same but at least one of the heads could not deal with the added current. (It's been long enough ago that I can't remember whether it was erase, record, or both. End result, the core(s) melted. I have no idea whether this prompted a design change or not so I'd advise doing not messing with a machine's operating limit until you do a lot of research.
 
FWIW I had a tech calibrate my A-3300SX for 456, this was a long time ago, when I didn't know a nano weber from Potsie Weber so I don't know if it was cal'd at 250 or 370 or what exactly.

Don't know if this helps, but per the manual, the Otari MX5050BII-2 are factory calibrated for 320nW/m at the high setting. The peak LEDs are calibrated for 1040 nW/m which I think per the manual is +15dB. The Otari seems to have a pretty stout transport. 499/GP9 are just slightly thicker oxide coating, (base is the same. ) oxide is 600 u vs 500 u for 456 or 2.03 (499/GP9) vs 1.996mil (456). 2.28 overall for ATR all of that oxide, (base is the same.)

There are guys on Tapeheads that use ATR and SM900 on consumer machines without issue, so I'm assuming that is on machines calibrated for 406.
 
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Blue Jinn said:
per the manual, the Otari MX5050BII-2 are factory calibrated for 320nW/m at the high setting. The peak LEDs are calibrated for 1040 nW/m which I think per the manual is +15dB.
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i guess those Otaris could handle it anyway: +15db peek leds!!!??? interesting.
I'll have to look at any differences in those Otari MX5050 decks.

thanks for the info.
 
LUNE said:
I'm just trying to get an idea of what machines could be biased for the +9 tapes and would have a chance of holding up to the added strain of the thicker tape.
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You could try out the thicker tape and see if the capstan pinch roller pressure goes up very much. Assuming you can bias the tape, you should still calibrate to the rated operating level for the machine (+4 over Ampex for the Otari) to leave reasonable headroom on the record electronics. Of course, that illustrates that there isn't much reason to try to do this, since even if the tape can handle higher levels, the machine probably can't record them without distorting, so what's the point?

Cheers,

Otto
 
I run my Otari MX5050 half track at +9 with ATR tape. It is DELCIOUSLY good.

A bit of wisdom, though: ATR tape can be used at any operating level (+3, +6, +9) with amazing results. The tape's unique formulation gives it a lower noise floor at +6 operation than 456, SM911, and the like. You might find that you like it at +6, so give it a shot if you're inclined.
 
One more thing: If you want tape compression, you may want to go with SM900. You're likely to overload your deck's electronics before you get compression from ATR tape.
 
lo.fi.love said:
I run my Otari MX5050 half track at +9 with ATR tape. It is DELCIOUSLY good.

A bit of wisdom, though: ATR tape can be used at any operating level (+3, +6, +9) with amazing results. The tape's unique formulation gives it a lower noise floor at +6 operation than 456, SM911, and the like. You might find that you like it at +6, so give it a shot if you're inclined.
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Good to know. On a hub, you can buy 1/2" direct for $64, not much more than RMGI SM 468. I wonder if my 8-track could pull this off, too?

I'm impressed that the Otari can put levels that hot on the tape and not distort the rec electronics. If you are tracking that hot, it makes sense to calibrate at +9, to avoid overloading the line level electronics.

Cheers,

Otto
 
ofajen said:
Good to know. On a hub, you can buy it direct for $64, not much more than RMGI SM 468.

I'm impressed that the Otari can put levels that hot on the tape and not distort the rec electronics. If you are tracking that hot, it makes sense to calibrate at +9, to avoid overloading the line level electronics.
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The deck's amps work harder at +9 (versus +6) and that WILL take you closer to the deck's clipping point. In my opinion the best thing to do with my mixdown setup (Otari MX5050 MKiii-2, ATR tape, +9 operation level) is to not go beyond +1 VU. There's really no point to go further than that, anyway, but if you push harder you are risking the chance of distortion, not at the tape level but at the deck electronics level. I'm sure you can hit ATR tape at ridiculous levels before it will distort, but that means nothing if you're straining the deck's electronics to the point of distortion.

I've driven the input levels on my Otari beyond +3VU but why bother? At a +9 operating level there is SO MUCH usable dynamic range to use that it's really a pointless exercise to go beyond 0VU.
 
And for what it's worth, I've used a reel of ATR tape on my Tascam 48 (half inch, eight track) and at +6 I've found that dbx NR is virtually redundant. I'm really pleased with the result, except it does mean that I have to clean and maintain the deck a bit more often because the particle density of ATR tape is considerably greater than 456 / SM911 / [PEM|SM]468 and thus is prone to shedding slightly more oxide (as with 499 and SM900... it's just a fact of life).

I also personally don't believe the argument that ATR tape puts additional strain on Tascam's professional multitrack decks (48, 58, MS16, ATR60). Whatever difference there is seems negligible, and I'm not too concerned anyway because I'm typically using my machines only about 10-12 hours a week.
 
lo fi,
although I haven't had time, i've had several people with alot of reel to reel knowledge tell me to forget the rmgi stuff and only use atr on my 80-8. they all pretty much confirm what your saying here.........bias your deck to what it's supposed to be at and use atr only!
kinda counters what i had read only line about using only rmgi on tascam small decks.
 
purerad said:
lo fi,
although I haven't had time, i've had several people with alot of reel to reel knowledge tell me to forget the rmgi stuff and only use atr on my 80-8. they all pretty much confirm what your saying here.........bias your deck to what it's supposed to be at and use atr only!
kinda counters what i had read only line about using only rmgi on tascam small decks.
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Well, here's the thing. I will never say that ATR is better than RMGI or vice versa, because it simply isn't true. What I think needs to be understood is that some products are better for certain applications.

I think anyone who uniformly recommends one product over others for all applications is misinformed and misguided. In my experience, for example, I've found RMGI SM911, BASF PEM468 (now RMGI SM468), and ATR tape to all be fantastic products for a wide variety of purposes. It's knowing what sound you want for a particular project that's really key.

The music I make just doesn't sound all that great on SM911 (or at all, I suppose some people would say :)) and so I experimented with a couple other varieties and found one that works best for what I'm doing. I still switch between the three varieties of 1/2" tape that I have in my closet, because I know them each well and I know what I can expect from each of them.

I think the argument on which tape is better is a bit extreme and also misses the point. People like what they like for different reasons, and often will like one product for one application and a different product for another application. It's about letting your ear decide, because the market has already decided that all of these products are good enough to buy.
 
lo.fi.love said:
The deck's amps work harder at +9 (versus +6) and that WILL take you closer to the deck's clipping point. In my opinion the best thing to do with my mixdown setup (Otari MX5050 MKiii-2, ATR tape, +9 operation level) is to not go beyond +1 VU. There's really no point to go further than that, anyway, but if you push harder you are risking the chance of distortion, not at the tape level but at the deck electronics level. I'm sure you can hit ATR tape at ridiculous levels before it will distort, but that means nothing if you're straining the deck's electronics to the point of distortion.

I've driven the input levels on my Otari beyond +3VU but why bother? At a +9 operating level there is SO MUCH usable dynamic range to use that it's really a pointless exercise to go beyond 0VU.
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There are two potential problems that should be avoided. The first is possibly overloading the record electronics dynamic range and causing distortion in the electronics trying to record a signal to tape. That is just a matter of how hot a signal you are trying to put on the tape and what the record electonics circuit is capable of.

The second possible problem is overloading the input electronics at the line level. The standard line level is +4 dBm. If you set up the machine at +6 re Ampex and then record 3 dB hotter than you normally would, you will be putting the same levels on tape as if you had calibrated at +9 and then run things normally, but the line level signals will be 3 dB hotter. So my point was just that if you find you can really put 3 dB more signal on the tape without distorting the record electronics, make sure to go ahead and calibrate the machine at +9 so you don't run the risk of overloading the line level stages.

Cheers,

Otto
 
I think that you have Line Level and Operating Level confused with each other. The two are different and are not related in any way.

What I'm talking about is the record amplifier. The amount of current coming across the wire has no relation to the amount of magnetic energy transferred to the tape via the tape heads. What does determine the amount of energy transferred to the tape, however, is your recorder's record amplifiers. Essentially what the record amps do is amplify the signal coming off the wire and send that electrical energy to the heads (oversimplified, I know, but it's close enough).

Some recorder amplifiers simply don't have the "mmph" to print a signal at a +9 operating level, and regardless of whatever line level the deck runs at (+4 in typical balanced IO operation or -10 in typical unbalanced IO operation), the increased pressure on the amps will cause distortion as you're basically asking it to output more energy than it is capable of.

It's true, though, that +3 over 0 VU on a machine set up for a +6 operating level is approximately 0 VU on a machine set up for +9 operation. I'm not sure why you'd want to do it that way, though, because you've drastically reduced the amount of headroom you have before distorting on tape.

There isn't any way to "outsmart" the electronics and it's best to work within accepted tolerances and use the machine (and tape) as intended.
 
lo.fi.love said:
I still switch between the three varieties of 1/2" tape that I have in my closet, because I know them each well and I know what I can expect from each of them.
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I assume that means that you recalibrate / rebias when you switch tape?
do you find that 'inhibiting' to do casually? or is it pretty accessible on the MX5050 MKiii-2?
 
LUNE said:
I assume that means that you recalibrate / rebias when you switch tape?
do you find that 'inhibiting' to do casually? or is it pretty accessible on the MX5050 MKiii-2?
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I was speaking specifically about my Tascam 48. I switch between RMGI SM911, ATR, and BASF PEM468 without recalibrating and I get good results.
 
lo.fi.love said:
What I'm talking about is the record amplifier. ....
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Yes, and we are in total agreement on that point.

I was trying to make an additional point about the relationship of reference magnetization level, standard recording level practices using a SVI (VU) meter and possible consequences for the line level input and output stages depending on the choices one makes, but really... no one cares. It's a minor point. So, forget I mentioned it. :)

Cheers,

Otto
 
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