Revox A700 Rare Tapes

Auntie Beeb with her miserable face, eh?

Respec' to you for finding them, and for wanting/hoping/trying to save them.

Sorry I can't help, but I wish you all the best,

John

Auntie has so much other tape to save. Ok thanks for the post anyway.

My congrats on finally being animated!

Mike

Mr Trueman thank you for the tip off. I wrote to record producer to try to contact the lucky man with two A700s. I need A 700 as some are recorded at 15cms/sec so the A77 is no good for both jobs. A700 are scarce like hens teeth.

Glad to be of service Squire. As for the hens teeth! Ya got to catch them when they are young

Hello Croc Dunoon

Magnetic tapes on reels or spools has a bad habit of "print-through" from one layer to adjacent layers.

What you may well have, is a lot of garbled sounds.

VHS Videotapes do also have "print-through", unless approximately each 12 months the tapes are fast forwarded and then rewound, to minimise the problem.

CD archival life for top quality is approx 30 years, DVD archival life is a bit better at 50 years, if you buy the top brands.

On what media do you intend to re-master those tapes?

The media has altered several times in my lifetime, from wind-up gramophone and 78rpm shellac records, through 45rpm and LP + EP records, then audiotapes, then 8-track cassette tapes, then Philips cassette tapes, then CD, DVD and so on.

Whatever media you record those tapes onto, you can never ensure longevity of the Media and/or a player necessary to be able to extract (listen to) the recording.

As for longevity, perhaps the best media has been inscribed clay tablets, then glazed and fired, but that is useless except for writing or painting.

Of course in a hundred years or so, no present CR4 reader is going to worry about it.

If you are in Scotland, surely there is a Museum (or two) who have a tape player you need to play those tapes, and in return for copies, may lend you an old Revox machine.

I wish you well, in your endeavours.

Kind Regards....

Doc
That sounds like a great project. It's funny, what with all the "advances" we've had in recording technology, that regular records still seem to be the most archival, presuming you take reasonable care in their storage. Heck, you don't even need electricity to listen to them but that would be prohibitively expensive to do the mastering.

Best of luck & please let use know how it all turns out!

regards

Andy

VHS Videotapes do also have "print-through", unless approximately each 12 months the tapes are fast forwarded and then rewound, to minimise the problem.

You are so right, Sparky. I followed the same procedure with all my CD's and DVD's and I do not have any problems with "print-through"

Hello indel

Yes, I have found the an invaluable assistant.

Kind Regards....

Oh, yes this is the tool. For rewinding my CD's and DVD's I improvised a device that worked, by required some acquired skills.

My device is based on the number of rails on the CD. Take the average perimeter length of a rail and multiply with the number of rails. It is a bit tricky, you have to count precisely the rails (I used a magnifying glass x100 and very sharp tip chuck). Now, use a bobbin and spool on it the same length of red thread. Here comes the difficult part: put a rubber band on the periphery of the CD. On a Singer sewing machine, use the rewind system for the bobbin and put the (now) rubber edge of the CD tangent to the thread with a pencil HB as an axes. Start slowly the winding of the bobbin. When there is no more thread, your CD is rewound. Pay attention to the sense of rotation, otherwise you have to redo the winding.

I have presented to the Patent and Trademark Office but those guys are square...

I understand that metal tape deteriorates over time. I know that these tapes should be treated and restored properly. I believe that this consists of baking in an oven at a certain temperature for eight hours etc. This is a specialised area I know little about. It is expenisve per reel and and I can't afford to restore this collection. I intended to take a chance and clone these by remastering back to 1/4 inch tape. Do a copy for me and a copy for the Museum of Scotland for posterity. Also I intended to convert the lot to MP3 and upload the collection to, Old Time Radio, or some other, free public broadcast via the internet machine. I'd like everyone to appreciate the collection. The top end tape players I need are expensive now. I'll try the museum but if know that if they take the collection for restoration, they'll claim copyright themselves or say the BBC has the rights. (Even though they have lost many of the early recordings.) So if I don't do this myself you can safely say no one will ever hear them, including me. They'll lie in a cellar somewhere at the museum awaiting a budget to conserve them. I am just going to do it myself. Any advice on a DIY restoration process for these tapes would be welcome.

I would in your case also make several high quality copies in MP3 or Ogg format to CDs or DVDs. Make sure that the copies are stored in alternative locations, "just in case".

Do not forget that really nothing is a good storage media over long periods of time, especially in Analog format.

I would digitize them asap.....using a high quality sound card in a good PC....

Keep DVDs & CDs away from light and do not let them get scratched on either surface, particularly the top one (non playing surface!) or handled by children.

Final copies should be made on an industry compatible Digital Tape drive (Data not tone).

I can digitize for you and return the copies, but I do not have the Revox tape deck at this time. That could be fixed I feel!!

Andy wrote: I would in your case also make several high quality copies in MP3 or Ogg format to CDs or DVDs. Make sure that the copies are stored in alternative locations, "just in case". Do not forget that really nothing is a good storage media over long periods of time, especially in Analog format. Hi Andy thanks for the information. I have a friend who has a DAT recorder is that what you mean by digital tape drive? That is a generous offer to digitise for me I may take you up on that. But I need to tell you there are 55 x 3 hour tapes. He seems to have used both sides so I don't know if that makes them 6 hour tapes or not? That's a lot of digitising. The good thing is he never skimped on cheap tape like Ampex. Nearly always, BASF. The early fifties tapes are BASF MAGNETOPHONEBAND. Every tape still has if celeophane cover and box. I'm not sure what people mean by tails out or talis in. I see there is some leader with a number he has marked on it at the beginning of the tape? How can one tell if that's tail out or in? Croc

No I did not mean DAT, that to me is not a proper way to go. I was never impressed with DAT for longterm storage, I have seen too many digital DAT tapes get chewed up.....you need about 3 copies of each piece of music to be a little bit safer!!!.

I mean professional 1/2" tape drives from StorageTek (Sun Microsystems today), IBM, DLT etc.. The types used in modern Computer Systems.

Of course at least 2 copies as all the music will go onto one LTO tape when digitized.

I can copy onto DLT4000, 7000 and SuperDLT, IBM LTO, Seagate LTO drives. The tapes when properly stored offer a storage life of about 30 years with less than 5% loss of signal strength.

I would personally recommend IBM drives with IBM tapes and also DVD copies (together, not one or the other), that way you can easily play the music via a PC from DVD and you have the original Master copies in LTO format.....

"Tails in or tails out" is not a terminology that I am familiar with, but someone here on CR4 will be....it may have to do with the start of the tapes you have, but I am only guessing.

The limited infos that i found about the Revox decks was that 15 IPS was not a standard, but 19 was....is my info incorrect?

I could probably get hold of a DAT drive and make such copies for you, but we need to talk off line from CR4....email me over CR4 sometime if you wish to further the contact....I leave it up to you.

Hi Andy, "Tails out" refers to the tape as it is wound on the reel. If the tape needs to be rewound before you can play it then it was stored tails out.

The reason for tails out storage is the tape lays upon itself so that print through is always behind the original recorded signal instead of leading it (pre-echo).

If the tapes are stored "tails in" (ready to play) the print through will occur before the recording and will be heard as a faint but recognizable portion of the following recorded information.

Thus, if the tapes suffer from print through, you'll hear in the quiet places, something of the music faintly, and then a repeat of that same information much more loudly as the actual recorded information is played.

Print through is the bane of music collectors who deal in original tapes and has destroyed many "one of a kind" tapes. My friend recently acquired an original Beatles rehersal tape made just after the group renamed itself from its original name of "The Quarrymen".

As the tape plays you can hear Mc Cartney and Lennon discussing the arrangement for "I want to hold your hand" and the first evolutions of the song. Unfortunately all this lovely information is corrupted by the heavy pre-echoing of print through as a result of being stored 'tails in' for over forty years.

Great info, thanks.

Revox machines run out at quite a bit of money today, are there alternative machines that can playback at the same speeds? With a similar quality or better?

Baking tapes before playing is easy, 1; make sure the tape is wound level/even on the spool no tape edges sticking out. If you don't do this the edges can overheat. 2; get a carboard box to hold the tapes put spacers between them fo the air to circulate or just do one tape at a time. 3; cut a hole in the box and put a hairdryer nozzle into the hole try it out first with no tapes!! you are looking for a temp of 110-130 degF. 4;get a suitable thermometer the kind used in kitchens to check meat temps and poke it into the box. 5; when you are happy with the temp etc put your tapes in and bake for 4 or five hours, keep an eye on the temp! 6; let them cool then play them, you can rebake as often as you wish.

Since both of these recorders are two track models operating with quarter inch wide tape there are many like models from the 60's and 70's which will work equally well. Nearly all have the 3 &3/4, 7&1/2 and 15 Inches Per Second tape speed selection.

As Sparky pointed out, print through is a major problem with tapes stored 'heads out' (ready to play). The proper way to store tapes is 'tails out' (requiring rewinding to play).

You can recognize print through when there is a pause in the music or the vocal and in that pause you hear the next few notes or lyrics to come. If the tapes were stored tails out the print through will be smothered by the much more intense magnetic image of the original recording.

If this has occurred there is a way to eliminate this print through using a "Keypex" (keyable programmable expander) machine which was also built back in the early 70's or you can "ride the fader" as you record from the original to the new medium.

A tip here if you choose to ride the fader is to run the master and the copying machines at the slowest speeds which still yield fidelity. For instance copying a 15IPS tape running at 7 &1/2 IPS to a recorder operating at 7&1/2 IPS will allow you twice as much time to edit out the objectionable print through. When the copy is run at 15IPS the editing will be almost unnoticeable.

If you have a machine which has audit windings in the recording head you can use this synchronous timing to your advantage by punching up "record " in each one of the places print through occurs on your copied tape.

This eliminates the print through and yields the background hiss of tape asperity noise giving an audio illusion of continuous virgin recording. This technique is used by many museums in restoring recordings having been developed by Deusch Grammaphonen for restoring pre war recordings by the Berlin Philharmonic Orchestra.

As you can see there are a number of ways to treat your tapes and make them quite acceptable. One caution however. Many of the older machines mentioned have tape tensions far greater than aged tape can withstand. It would be wise to reduce the tape tension to the very minimums to reduce stretching and loss of the magnetic coating due to the high scrubbing action across the heads.

I wish you lots of luck in this endeavour. As you become more experienced you will able to transcend these more primitive restoration techniques and accomplish your remastering digitally but learning about editing is what this is all about.

Thanks taejonkwando,

Most of mine are 3¾ IPS and a few 7½ IPS. No problem with the print through but didn't know about the Tails in or out. And here I thought the guy was lazy who I got most of my tapes from. Doh!

Some of my tapes are over $100.usfrd (US Federal Reserve Dollars) like the one pictured above and the dust, smoke, sparks, etc. of the shop will not help their fidelity at all. Besides hands covered in coal dust and iron oxides can't change out the tape.

I have 2 Tape, players both Japanese that do a great job even though they were bought during the Viet Nam war.

I plan on re-mastering my albums while I'm at it. My brother-in-law has his own recording studio in his house (big house) If I can pull it off the remix will be in surround sound. Led Zeppelin should sound even better if that's possible.

If Dad will let me I'll do his 78s then also. Can't do his tube recordings though, no player.

Thanks again for the good information

Brad

Hi Taejonkwndo thanks for that information, you got me thinking in the right direction about the capture process, particularly regarding, speed of playback. However, it would be a lot easier if, as you say, both machines were indeed, 2 track, but they're not. The Revox A700 recorded 4 track. So in this collection their are: old mono reels, from the 50's (it doesn't say what machine those were recorded on, or at what speed); 2 track reels recorded on the A77; along with 4 track from the A700. The speeds vary depending on how much tape he had left on each reel for recording. Recording at 15ips is more expensive as you use twice as much tape to record the same thing. The faster the tape turns per second the more information can be recorded and therefor the better the sound quality. The A700 was also recording in centimetres ie 19 cms metric just to complicate matters. Some of the A700's had an add on that was a speed contol to play any speed. That's what I need. Also, a mono, a two track, and a 4 track machine. Yikes! ,

Hi Croc Dunoon, You are correct about the four track A700. As I sent my first response off to you I had one of those "Is that correct?" moments when memory fails to provide complete assurance so I called a friend who has been in the recording business for years and he gave me the right information.

In any case monaural tapes will play on a two track or a four track machine since the information is recorded across most of the tape width. Two track tape will play on a four track machine with most of the information appearing on the recorder's tracks one and three although there will be bleed over to tracks two and four.

Maintaining stereo separation can be fine tuned by adjusting the playback head up or down to track the highest fidelity tracks on the tape. Your main difficulty will come from tapes which were recorded in both directions. Here you will have use the two track machine and adjust the playback head for least "bleed over" from adjacent tracks if you haven't been lucky enough to find a four track machine.

As you explore this collection you will find one evil nemesis and that is the imprecise speed control of those early machines which can yield a wobbly audio. My buddy also mentions that during the initial transfer to another multitrack machine, use a spare track to record a constant audio tone. This tone is used as a guide to find the places where the audio tape slowed. The transfer tape is played back against the tone from the generator and the off speed recording of the original becomes readily apparent by the divergence of the recorded tone when played back against that of the tone generator.

Correcting speed control is done using a Variac (variable transformer) between the mains and the playback recorder. You'll also need a digital timer capable of one hundredth second display and an audit sheet which tells you exactly when the speed deviation occurs. Then you'll need to practice on test tapes until your corrections make the speed change undetectable. At that time you are ready for your final mastering and a job with almost any record company or audio library.

Again, good luck. This is an endeavour which will drag you deeper into audio that you ever imagined but as you begin to master the process you will be among the very few who can save the sounds of the past.

I must take issue on the speed control by Variac. All Revoxs from the A77 onward use an on board speed reference and are immune to speed variations caused by variations in mains voltage or frequency (apart from some early B77s which had a defective capacitor in the speed control circuit!)

All Revoxs from the the A700 and B77 onward have speed control socket so it is easy to add vari-speed. The standard PR99s had a -33% +50% vari-speed control built in.

As well as Revox, consider Neal Ferrograph equipment as a substitute (usual disclaimer). Their broadcast-quality machines can sometimes be found. 3³/₄, 7¹/₂ and 15ips tape speeds can be found on these machines.

Depending on the original tape recording format, bear in mind that a 2-track stereo machine can replay both 2-track stereo and single-track mono recordings, and that a 4-track machine can replay 4-track stereo and single-track mono; a 4-track machine will give poor quality on one audio channel if used to replay 2-track stereo recordings, as the tracking will not align with that if the original recording.

I have a 4-track model of a Revox A700 available for sale in the US. Make an offer. It's in very nice shape. I am an unregisterd user. Please email me at the below address if interested in the machine.

Jeremy K.
jer@jeremykuzniar.com

Good news. I have access to an A700. It's on my desk as I type, as I'm using it to try to capture some old family recordings. Bad news is that I'm way down south, in Eastbourne, East Sussex. If that's any use to you, mail me via rs44@brighton.ac.uk.