Open R2R Tape best lubrication

[Analog Pitstop]

If you know, or if you heard from experts, which tape name&model (&year?) had the best lubrication properties?
Any extended opinions (i.e. teachings) on the subject are welcome.
Thanks,

 

[gyraf]

We need more info to answer your question: The XY Problem

 

[soapy_goat]

If you know, or if you heard from experts, which tape name&model (&year?) had the best lubrication properties?
Any extended opinions (i.e. teachings) on the subject are welcome.
Thanks,

If you're worried about shedding, buy new tape. I use SM900 or SM911, good stuff

 

[Analog Pitstop]

Sorry, I thought is clear.
The basic problem is the high frequency flutter, as usually is in the context of a 100% normally operating Open R2R. The flutter bandwidth is assumed by free choice to defined as +/-10-20% of the frequency of the recorded tone). This choice is based on the usual spectral analysis of a normally working R2R machine in full specs and having original components very close to "as new" condition.

The topical problem is to learn the Top-3, -5 or -10 of R2R tapes (usually brand new - virginal or non-virginal, but also maybe not so brand new - I have no reasons to exclude this category in so far) organized by this criteria.

I am looking especially for any kindly shared info from the high-end studio professional experience places, as mostly only this category would have had a keen eye and a financial-backed scrutiny on batches for this property. As usual, the comments from the former members of R&D in this precise field, either professionally or hobby wise, are extremely high appreciated. For example, the tape manufacturers.

Note: Topics like shedding or other age-problems of the tapes, are NOT in the scope of this question. Only the 100% functional tapes should be in consideration for proposals in this Top-3, -5 or -10.

Thanks!

 

[Analog Pitstop]

For example, the result of SM911 brand new tape on Revox B77 speed 7.5" with DIN 0.02% peak W&F.
If Flutter association for this "noise bump" is correct...

 

[Analog Pitstop]

-> other tapes (SM900, LPR35, PE41, UD-X, Sony, etc), giving similar results, maybe slightly depending on how good their W&F numbers (standard definition, 0-4Hz and 4-100Hz) are. For each tape the B77 machine was bias-aligned accordingly.
-> same tapes but on other machines (Sony F&F heads, Sony non-F&F heads, Teac X2000R heads, STM heads, etc.) give diferent results in terms of noise bump shapes, but roughly similar trend in terms of bump area.

Maybe the most serious studios have possibility to order special formulations (Top 3-, 5- or -10?), or batches (!) with improved tape lubrication? I do not like to jump on conclusions. I better ask the experts for help, maybe I have something wrong in my setup, or maybe I have a wrong understanding.

 

[Analog Pitstop]

Also:
-> the same tapes in quasi-virginal condition (full width pre-erased), then remove the tape physical contact with the Erase & Play heads by a precision/thin soft cotton swab (or soft felt) layer during REC. Then remove the tape contact on Erase & Rec heads during PLAY for Flutter measurement. The results are significantly better (ca -10dB less noise bump).
These latter advanced measurements were done only on B77 - due to limited available hobby time.

 

[Analog Pitstop]

In conclusion, there is this question: maybe I do not have the right tapes?
Because, I refuse to believe this is the state-of-the-art for studio recordings.
(well I know that I do not have a top-notch studio machine, but for these Flutter measurements and for the physics&engineering behind them I think I should be quite close to their level. Or not?)

 

[gyraf]

I have never heard this theory before - that there should be significant connection between W&F and tape lubrication. I know that we in the studios never ever discussed this, and we were pretty deep into tape and its optimisazion

But perhaps related:

Back in the 1990'es when the high-output tapes became fashionable (3M996, Ampex499), these suffered quite heavily from print-through when stored for longer periods of time (~30days+). Both companies tried to remedy this by applying backside lubrication to make the tape slippery enough that it would slightly move while on-reel, thus reducing print-through by moving/spreading/smearing the tape locations.

But this turned out to be a major problem for those of us that ran pinchroller-less tape recorders like Otari MTR90 and MTR100: These depend on firmly grabbing the back side of the tape for accurate tape handling, and with the new high-output tapes we had excessive slippage and very poor tape-locator stability.

3m/ampex told us to up the tape tension, but this just wears down heads at an excessive speed

Eventually both companies came up with a decent compromise between parameters (around 1994?), but with the cost of at least some additional head wear.

/Jakob E.

 

[ruffrecords]

Whale oil was the best. Unobtanium these days.

Cheers

Ian

 

[Analog Pitstop]

@gyraf : Thanks for sharing this info.

Indeed, seems plausible.
For studio machines the total tape angle on heads is <10°, allegedly. This calls for higher tape tension. In turn, higher tape tension would have the effect of spreading the flutter noise bump bandwidth up to 20-30% of the tone frequency recorded. In the assumption that the noise bump area will remain constant, then the net effect is expected to be a smearing of the flutter noise bump.

Anyway: care for a simple measurement and analysis (like above) on one of your best studio machines and sharing it here? Just for reference. Can you tell also the tape tension value?

For non-studio machines which have the total tape angle around heads ca. 20° or more - and hence operating with less tape tension (SM 50-70gf): this situation create a more pronounced bump (as shown above in the spectrum). I think this case calls a for better tape lubrication on the oxide side!

Eventually both companies came up with a decent compromise between parameters (around 1994?), but with the cost of at least some additional head wear.

which tapes precisely?

 

[Analog Pitstop]

Whale oil was the best. Unobtanium these days.

Cheers

Ian

another kind of oil (yet, a snake type) was the BAM (boron aluminum magnesium) coating "developed by NASA"
The inventors were soon expelled

 

[Ivan K.]

Hi, I think more research is needed to assure yourself that this is not a machine specific problem with your B77. Many pro machines have flutter rollers (such as my Sony APR5003V), that have to be maintained from time to time. You should also check results at different tape speeds and machines if you have access to others.

It's also worth trying some new and existing tapes such as the (US made) ATR standard thickness and their new ATR MDR36 1mil, long play tape, or some old Agfa PEM468 or BASF, maybe still available in Germany. If you can find low-print tape like 3M 808, it would be worth a try.

Please tell us the measurement conditions and equipment so we can check to see if we get similar results.

Regards,
Ivan

 

[Analog Pitstop]

Please tell us the measurement conditions and equipment so we can check to see if we get similar results.

I'd be happy to fill out all your questions. Send me a list with parameters - to insure compatibility. Many parameters are already given, but please include them in the list nonetheless, to learn which ones are relevant or critical.

to assure yourself that this is not a machine specific problem with your B77

as said, I have operational a B77, a TC399 and a TC640: all show similar bumps. The Sony-s a bit less, helped by scrap rollers. B77 does not have them.

Tapes: only models I listed (BASF is included, as LPR35 and DP26). Best results (least bump area) I have with AGFA PE41. Second is BASF's LPR35.
I do not have the special kinds 468 or 3M808.

Source&Measurement: Picoscope 4262

 

[Analog Pitstop]

The measurements with more REC heads (Teac, STM, etc) are using the B77 platform. For this, a dedicated modified-B77 platform for heads to accept any models is used.

 

[Analog Pitstop]

You should also check results at different tape speeds and machines if you have access to others.

All 3 machines I have (B77, TC399 and TC640) can do 3.75 and 7.5ips. For all machines the flutter bump is there on both speeds. For each speed, the trends between machines are very similar too. Well, some have flutter rollers and some not, while other have better heads and electronics (S/N) and others not... These factors can be easily accounted for.

Also, because the 3 machines might have different W&F specs for different speeds, then I have also checked the following:
- recording 7KHz at 3.75ips and play at 7.5ips.
- recording 14KHz at 7.5ips and play at 3.75ips
(and actually the same dual approach for many more frequencies)
For each frequency, the results were pretty identical with Rec&play made at the same speed.
Funny, the tape choice was also identical: best results with PE41 (old tape) and the rest... are similar but measurably not as good.

Yesterday, I took out the capstan shaft from B77 and today I gave it for measurement (0.3um precision). But the machine is pretty booked and I will have the result only in a few weeks.
If needed, I will be able to grind it with 0.3um precision as well. We will see.

Meantime, some external opinions and examples will be very useful! If possible. I hope.

 

[Analog Pitstop]

Today I bought a brand new Studer B67 capstan motor (9.5-38) NOS.
I hope to manage to integrate it into B77 without changing the electronics and the mechanics too much.