Advice about tape for Revox A77

[Sotsirc]

Any advice on good tape for this machine? I'm looking at various RMG tapes but I can't say that I understand the difference between them (All 1/4", of course).

RMG SM900 1/4" 762M NAB

RMG LPR 35 1/4" 1100M NAB (slightly cheaper)

RMG SM91 1/4" 762M NAB

RMG LPR 3514" 1100M, PLASTIC REEL

[audioexmachina]

The LPR options are for long-play, thus the tape is thinner.

The other two are thicker, with the 900 being a +9db tape (similar to Quantegy GP-9). The 911 is a +6db tape (Quantegy/Ampex 456).

Said that, the LPR is a +6db thinner version of the 911.

The 911 is the most balanced choice, but if you want to compare further please check out the tape docs at Tapes

[mrtapeguy]

Originally Posted by Sotsirc

Any advice on good tape for this machine? I'm looking at various RMG tapes but I can't say that I understand the difference between them (All 1/4", of course).

RMG SM900 1/4" 762M NAB

RMG LPR 35 1/4" 1100M NAB (slightly cheaper)

RMG SM91 1/4" 762M NAB

RMG LPR 3514" 1100M, PLASTIC REEL

Audioexmachina is essentially correct - most people use the SM900 on machines that can handle a tape that hot; otherwise they go with the SM911. Some people also like the SM468 which is a lower print tape but less often in music as it has less output/headroom.

These tapes were previously made by Agfa which became BASF and then Emtec before RMG.

We stock all these tapes and will also be bringing in the one other manufacturer shortly - ATR Magnetics. We don't get a lot of feedback on their product other than from a few people who simply don't like the RMG.

More product information here: Pro-Tape.com - RMGI Open Reel Audio Recording Tape Sale

We put out news on recording as well as video and film on Facebook (Pro-Tape Staff) and Twitter (@protapestaff) if you are interested.

Craig

[audioexmachina]

Originally Posted by mrtapeguy

Audioexmachina is essentially correct - most people use the SM900 on machines that can handle a tape that hot; otherwise they go with the SM911.

We stock all these tapes and will also be bringing in the one other manufacturer shortly - ATR Magnetics.

Craig

Nice to learn you stock tapes, Craig, I've added your URL to the 2012 tape dealers list at audioexmachina blog. Thanks.

[mrtapeguy]

Thank you! Much obliged!

[Sotsirc]

Excuse my ignorance, gentlemen; but what does + 9dB and + 6 dB mean in this case? Does the tape have an inherent loudness? How does this relate to headroom when recording?

P.S Is RMG SM91 1/4" 762M NAB the same as SM911?
Thanks

[HudHudson]

Originally Posted by mrtapeguy

Audioexmachina is essentially correct - most people use the SM900 on machines that can handle a tape that hot; otherwise they go with the SM911. Some people also like the SM468 which is a lower print tape but less often in music as it has less output/headroom.

These tapes were previously made by Agfa which became BASF and then Emtec before RMG.

We stock all these tapes and will also be bringing in the one other manufacturer shortly - ATR Magnetics. We don't get a lot of feedback on their product other than from a few people who simply don't like the RMG.

More product information here: Pro-Tape.com - RMGI Open Reel Audio Recording Tape Sale

We put out news on recording as well as video and film on Facebook (Pro-Tape Staff) and Twitter (@protapestaff) if you are interested.

Craig

Welcome to Gearslutz, Dick!

[audioexmachina]

Originally Posted by Sotsirc

Excuse my ignorance, gentlemen; but what does + 9dB and + 6 dB mean in this case? Does the tape have an inherent loudness? How does this relate to headroom when recording?

The db values reported for each individual tape refer to the optimal operating level. That would be the recommended magnetic flux density when recording and the related electrical level you can read on the VU meters.

0db is the original reference level, set by Ampex to 185Nw/m2 (Weber per square meters). Now, (note that here +6db means doubling some reference value) a 370Nw/m2 would be a +6db tape, being 370 the double of 185.

250Nw/m2 is +3db and 520Nw/m2 is +9db, again, referenced to the original Ampex value.

If your Revox wasn't recalibrated, it's probably set for 250Nw/m2 (+3db). That means that the VU reads 0dB when actually the tape is working at +3db (it's optimal level). When you mount a +6db tape such as the 911 and do not recalibrate the VU meters, then you should hit the meters at +3db (that's +3db provided by Revox calib plus another +3db to reach the optimal level at +6db for the 911).

So, regarding the original question, yes, that means more headroom.

Note that a +9db tape requires such an hotter signal on input that some of the electronics of the A77 may distort, that's why I recommended a more balanced +6db tape.

Originally Posted by Sotsirc

P.S Is RMG SM91 1/4" 762M NAB the same as SM911?
Thanks

Don't know the 91, I thought you meant 911.

[Plush]

Your A77 can run the SM911 tape well. It cannot run the SM900 optimally because it was designed before the era of high output tapes.

You must calibrate your machine, something a good ReVox tech can help you with.

[mrtapeguy]

Originally Posted by HudHudson

Welcome to Gearslutz, Dick!

Much grass - not new to the forum but certainly haven't been here in a LONG time.

cb

[u b k]

Depends on the sound you want to hear, and how much tape effect you want (or don't). On that machine, I'd be playing with some old Scotch formulas for a nice sepia-tinted tone, or 90's era Quantegy 456 for something more rock and roll with a thick, grainy, saturated vibe.

+6/185, generously overbiased for extra hf sat, natch.


Gregory Scott - ubk

[Sotsirc]

Originally Posted by audioexmachina

Don't know the 91, I thought you meant 911.

Thanks for your reply! This might just be a misprint, since the box on the photo next to the text says 911.

[Sotsirc]

Originally Posted by audioexmachina

The db values reported for each individual tape refer to the optimal operating level. That would be the recommended magnetic flux density when recording and the related electrical level you can read on the VU meters.

0db is the original reference level, set by Ampex to 185Nw/m2 (Weber per square meters). Now, (note that here +6db means doubling some reference value) a 370Nw/m2 would be a +6db tape, being 370 the double of 185.

250Nw/m2 is +3db and 520Nw/m2 is +9db, again, referenced to the original Ampex value.

If your Revox wasn't recalibrated, it's probably set for 250Nw/m2 (+3db). That means that the VU reads 0dB when actually the tape is working at +3db (it's optimal level). When you mount a +6db tape such as the 911 and do not recalibrate the VU meters, then you should hit the meters at +3db (that's +3db provided by Revox calib plus another +3db to reach the optimal level at +6db for the 911).

So, regarding the original question, yes, that means more headroom.

Note that a +9db tape requires such an hotter signal on input that some of the electronics of the A77 may distort, that's why I recommended a more balanced +6db tape.



Don't know the 91, I thought you meant 911.

Very well explained, thanks again.

[Plush]

Please know, however, that it is never a good idea to not re-calibrate the machine when you receive it. Calibration of repro and record to your tape type is always required. Seek out a tech near you.

[Sotsirc]

Originally Posted by Plush

Please know, however, that it is never a good idea to not re-calibrate the machine when you receive it. Calibration of repro and record to your tape type is always required. Seek out a tech near you.

I will.

[audioexmachina]

Originally Posted by Sotsirc

Thanks for your reply! This might just be a misprint, since the box on the photo next to the text says 911.

I've noticed an SM91 at thomann.de, according to google that seems the only shop carrying that product. Misprint, I'd say.

[audioexmachina]

Originally Posted by Plush

Please know, however, that it is never a good idea to not re-calibrate the machine when you receive it. Calibration of repro and record to your tape type is always required. Seek out a tech near you.

Yes, absolutely. I mentioned a not re-calibrated machine for the purpose of explainaing (in a simplified way) how operating levels dirft when changing tape formulas. My explanation makes sense only if we start with some known calibrated state (what I mentioned as possibly an initial +3db setting).

[stevevdb]

if you want to use studio master 911 on a revox A77 you will need to do some repairs on the 7 plug in cards inside the machine.

all the potentiometers and condensors.

[audiotech]

Originally Posted by steve vdb

if you want to use studio master 911 on a revox A77 you will need to do some repairs on the 7 plug in cards inside the machine.

all the potentiometers and condensors.

Exactly why would this Have to be done if the components are working properly?

Dennis

[stevevdb]

Originally Posted by audiotech

Exactly why would this Have to be done if the components are working properly?

Dennis

The parts are over 30 years old and the condensors are usually aluminium electrolyte which dry out when not used. I repaired over 50 revox machines and I always do a revision of the circuits even when they're okay. Repairing the circuit boards and recalibrating the machine provides you with excellent soundquality.