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Revox B77 Tech in SFL? Recorders, Players & Tape Machines
Old 7th September 2011
  #1
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Revox B77 Tech in SFL?

Hi Guys,

Does anyone know any techs in the South Florida area that can service a recently purchased Revox B77? I want to have the heads checked and have it prepared for ATR tape that I just purchased. The guy who owned it before me was using old Maxwell tapes. I think it might be a good idea to have it properly serviced for the ATR Tape.


Thanks in advance,

Luis
Old 7th September 2011
  #2
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I'm not sure it has enough internal headroom to take advantage of ATR tape. Do you have a manual? It's a good idea to learn to service such devices yourself because the few people who are actually competent to service them often refuse to service them.
Old 8th September 2011
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Yes I actually that is one of the reasons I wanted to speak to a tech, was to learn the proper maintenance for it, and to have him also look at it. Also Wado not many people selling new tape these days. I went with ATR cause they, I believe, are the only people still producing it. Not sure about that but they were the only people that I have found so far online. So I bought 1/4" reel of their material. The previous person was using Maxell Tape, which sounded fine but I don't believe they make reel tape anymore.
Old 8th September 2011
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RMGI makes a couple of 3M's formulae (thought not as well from what I hear) and Quantegy isn't in production, but still has NOS 457 on 1800' reels. 457 is the same as 456 but with a thinner base, which will give a better wrap on the heads at the cost of higher print-through. Though the only time I've found print-through to be a problem was when the tape wasn't stored properly. I don't think Maxell was ever really considered a "pro" tape, but 457 and RMGI's 911 will be the closest match to it from current manufacturers.

Materials you'll need before doing anything: Han-D-Mag degausser. Q-tips, 99% isopropanol (I think you can get it at Fred Meyer, which will be cheaper than a medical or electronics supplier) and and NAB, MRL calibration tape, most likely 250 nWb/m but it depends on the tape you use. I have 250nWb/m tapes for all my decks and if I want to hit the tape harder, just figure out mathematically where the meters should sit. You'll also want some plastic trimmer screwdrivers for making adjustments.
Old 8th September 2011
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Thank you for the shopping list I am actually shopping around for some of the stuff, however what is a NAB?
Old 8th September 2011
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"North American Broadcasting" standard reproduction EQ for tape recorders. Not to be confused as IEC, which is the European standard. Some tape recorders can do both, but I think yours is NAB only and using an IEC alignment tape will lead to inaccurate alignment.
Old 8th September 2011
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Besides being a wealth of information, the MRL site has a conversion chart for using an IEC tape to set up an NAB deck.

MRL Calibration Tapes

and specifically

http://home.comcast.net/%7Emrltapes/eq-shift-tables.pdf


GR
Old 9th September 2011
  #8
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in answer to your question...Yes
Ross Alexander
Synergetic services

305-947-7372
Old 9th September 2011
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Thanks Wado for all your help man good stuff. Greg those sites are just epic in the amount of information that they have. I have a lot of reading and learning to do . And thanks Mike I'll call him on Monday to schedule with him!
Old 10th September 2011
  #10
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Quote:
Originally Posted by wado1942 View Post
"North American Broadcasting" standard reproduction EQ for tape recorders. Not to be confused as IEC, which is the European standard. Some tape recorders can do both, but I think yours is NAB only and using an IEC alignment tape will lead to inaccurate alignment.
FWIW NAB stands for "National Association of Broadcasters."

There are two IEC curves. One is the NAB and the other used to be called CCIR.
Old 12th September 2011
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Right, I don't know what I was thinking (NAB definition). When one says IEC, it generally means CCIR, IEC2 is the same as NAB.
Old 12th September 2011
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Your Revox should have a little sticker on the connector panel at the back which will tell you whether it is NAB or CCIR eq. Once you've taken it out of its grey case and laid it on its back, most of the adjustments you need will be found on the bottom panel behind a paper label. If it has been adjusted in the past there will be holes in the label.

Most of what you need to know will be on the MRL website but, if you aren't confident, have the tech take you through them so that you can do them yourself in future.

I believe that RMGI LPR35 is closest to the sort of tape that it would originally have been set up for.

James.
Old 12th September 2011
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Very cool! Thank you James. Here is a picture of the unit that I bought I am excited to get the tape and start working on it!!


Old 14th September 2011
  #14
ORC
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B77 will run ATR just fine. Some folks set up for atr at 185 Nw/m. The B77 will easily do that. My old PR99 ran 3m 996 at 500Nw/m just fine. Sounded great too!
Old 14th September 2011
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I know a lot of people set up "hot" tape for low levels. The problem with that is it will be noisier than good old Quantegy 406 or something designed for lower level. Did you run tones to test the headroom for 996 at 500nWb/M? On my Otari and my TASCAM, I use GP9 at 400nWb/M and have about 14dB headroom before I get to 3%THD. I haven't tested my AMPEX yet because I've only really used it for repro work.
Old 15th September 2011
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Will this thing handle calibration at 520 nWb/m ?
Old 16th September 2011
  #17
ORC
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I'm, not sure if a B77 will do 500 or 520, the pr99 did 500 just fine. I'm currently running atr at 250 on my half inch deck. Its very quiet, and just sounds fantastic. Tons of headroom at 30 ips, and at 15 I still get some great tape vibe.
Old 18th September 2011
  #18
Quote:
Originally Posted by wado1942 View Post
"North American Broadcasting" standard reproduction EQ for tape recorders. Not to be confused as IEC, which is the European standard. Some tape recorders can do both, but I think yours is NAB only and using an IEC alignment tape will lead to inaccurate alignment.
This is because of the different hum frequencies in Europe & the US isn't it?
NAB = US, CCIR (AKA IEC1) = Europe.
Also only relevant up to 15IPS, as at 30IPS it's unified to AES standard.

My B77 is the HS variant, 7.5 & 15 IPS.
How can I tell what Emphasis EQ is used?

(EDIT - I was advised to use Ampex 407 tapes for this unit)

Last edited by neilwilkes; 18th September 2011 at 06:42 PM.. Reason: extra information added
Old 18th September 2011
  #19
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Bob Olhsson's Avatar
 

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Quote:
Originally Posted by neilwilkes View Post
This is because of the different hum frequencies in Europe & the US isn't it?
Not exactly.

What became the NAB standard was intended specifically for the Ampex model 300 tape machine using 3M type 111 or Audiotape brand recording tape. It included compensation for the high frequency and hum issues of that specific machine and tape combination. Those machines and tape were in such universal use here during the 1950s that it became standard to use that curve with all tape machines.

CCIR is a bit later standard that is closer to ideal although modern tape would actually benefit from the use of an even better, quieter curve.
Old 19th September 2011
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MRL has a good paper, proposing a better calibration that was written in the early 70s that would work well today. http://home.comcast.net/~mrltapes/mc...stering-eq.pdf
I actually record CCIR with slight emphasis in the high end. My goal is to add JUST enough high end that after the tape has sat for a while, it'll play back as if I had just recorded it minutes earlier with no emphasis. I thought about using MRL's proposed standard, but I'd be one of like ten in the world using it, which is pretty much the same reason the U.S. is still using a calibration that was obsolete over 50 years ago, fear of incompatibility. At least CCIR is close to ideal and there's plenty decks out there that will reproduce it just fine, including my AMPEX, my TASCAM, my Otari.
Old 19th September 2011
  #21
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It's worth noting that a fair number of people in the US started using CCIR beginning in the mid 1970s as an alternative to NAB with Dolby A or 30 ips.
Old 19th September 2011
  #22
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Quote:
Originally Posted by neilwilkes View Post

My B77 is the HS variant, 7.5 & 15 IPS.
How can I tell what Emphasis EQ is used?

(EDIT - I was advised to use Ampex 407 tapes for this unit)
Mine has a sticker on the rear connector panel which shows the Eq standard.

James.
Old 19th September 2011
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Quantegy 406/407 seems like it would be ideal. I'd think the thicker 406 would be fine as well but perhaps you'd get better wrap from 407 at the cost of higher print-through. I don't think Quantegy has any 1/4" 406 or 407 left though. They DO have 457 in 1800' reels, which should be fine also.
Old 20th September 2011
  #24
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Originally Posted by jamesp View Post
Mine has a sticker on the rear connector panel which shows the Eq standard.

James.
Nope - not mine. Must have fallen off (I did buy it 2nd hand) either before I got it or whilst it was being rebuilt.
All I have on the rear panel are the usual things - ins, outs, level adjustments (for calibration) and the various DIN sockets for remote units I sadly don't have.

@wado - I cannot remember where I got my 407 reels from, but will try & look it out.

@Bob - thanks for the correction - much appreciated. So much to learn with tape & machines.....
So the emphasis EQ could be either, and where the tape came from means nothing. Hopefully things will be properly documented on reels.....although I do confess that if it even looks like there may be a sticky shed issue with apes we send them straight to FX CopyRoom ratherthan try & handle it here.
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