Library wind on Studer Revox C270

[C_Campbell]

Hello all,

This is my first post here. I have substantial experience with open-reel recorders, having begun using a Tandberg and then a Nagra for field work along with a variety of studio decks for documentary and multi-image projects with my father as a teenager in the 1970s. I am now an artist (painter, photographer), but am still involved with audio, and currently engaged in beginning to digitize an archive of some six hundred tapes of spoken voice from the late 1950s and 1960s. Equipment-wise, I'm using an Otari MX-5050 BIII-2 to play back a handful of 1/4 track tapes, but the primary deck is a Studer Revox C270 1/2 track deck which I purchased in 1991. From the C270, I'm doing a 24/96 A/D conversion via Apogee Duet to MacPro, editing in BIAS Peak Pro 6.

I have long been familiar with the practice of storing tapes tails out, after playback at normal speed, so as to produce the flattest and smoothest tape wind possible. However, in studying the written material for the C270, I have discovered three references to an actual "library wind" function that I had never noticed previously:

1. Sales brochure. Listed in the original sales brochure for the C27x series, under "Transport Functions," as one of the machine's functions is:

   ? Selectable library wind

2. Operating Instructions. In the C270 operating instructions, on page 32, the possible settings of the DIP switches are listed. 

     Nr 3 ? ON ? Library mode wind on
     Nr 3 ? OFF ? Normal operation, library mode wind off

3. Service Manual. In the full C270 service manual, on page 3/2, is found the most detailed reference to the function of DIP switch 3:

     The following operation parameters can be programmed on the 8-bit DIP switch (SZ1):

          S3 ON = Library wind activated, adjustable with potentiometer (RA4)
          S3 OFF = No library wind

Given the precision with which these recorders were designed and built, it seems unlikely that all three of these references to this special function would be in error. The problem is that we have hardware and documentation related to "library wind" ? even a reference to which potentiometer to adjust to control its speed ? but not a word anywhere else about how to actually engage or activate it!

While an absolutely lovely deck, the C270 is slightly an odd duck, standing somewhere between the Revox and Studer families, nearly at the end of the development line. I know that on a number of full-fledged Studer decks one could touch the "Shift" key, and then a transport key to engage a slowed/library wind, but of course the C270 does not have a shift key, so perhaps it shares some parts and was intended to share some functions with decks like the A807, but this feature was never fully realized on the C27x series?

Recently, I have made attempts to get information both from current Revox/Studer service facilities in Switzerland, as well as from Revox/Studer service experts in the USA, but so far this feature seems to have flown under the radar. I have a lot of delicate  tape handling ahead of me, so if anyone has any information or leads to pursue, I would be most appreciative.
-----
Christopher Campbell
www.cbcampbell.com

[mikel]

Hello Christopher,

welcome to the forum.

i am not any Studer expert; but i do own a Studer A820 with library wind, which i use since it's so gentle on the tape and makes such a beautiful 'pack'. the interface on my A820 has some common things with the C270 just by looking at the pictures. many of the 'select' buttons on the A820 work by holding down the 'stop' button and then 'pushing' the selected button or toggle. you might just try that as it will not likely hurt anything.

others more knowledgable will likely chime in with the correct answer but if you are in a hurry it's just a suggestion you can try.

mikel

[ironbut]

Hi Chis,
Depending on the value of these tape, you'd do well to spend some time learning about archiving from the folks who do this for a living. There are a few here on this forum ( Eric Jacobs, Scott Smith, Marie O'Connell) and I'm sure they'd tell you that very often, the handling of old tapes is no trivial matter. Check out these web sites for some great info;
http://www.richardhess.com/tape/index.htm   Richard Hess is probably the dean of tape archiving.
http://www.theaudioarchive.com/  Eric Jacobs' beautiful web site. Wonderful conversion calculators that will come in handy
You should also subscribe to the ARSC list. Here's their forum; http://arsc-aaa.invisionzone.com/forums/index.php?  The forum is pretty new and not as well read as the mailing list. You can subscribe to the list through their home page.
I seem to recall that on the 270 (as with some of the other Studers) you have to reroute the tape for library wind but like I said, ask the experts.
Considering when these tapes were produced, I'm assuming that they're all acetate. If you've never worked with this tape backing and the problems that you might encounter (breakage, vinegar syndrome, LOL) be sure and read the entries in Richard's site. He's the man!

[Tubes n tapes]

Hi Christopher,

I think the development of the library wind feature on the C270 was never really finalized. It is partly functional, though.

First, you need to toggle S3 before you switch the machine on. The microprocessor apparently only reads the dipswitch settings during the initialization of the software. After you have done that, the library rewind mode is always enabled. That means that whenever you rewind it will do so at a slow speed. As far as I have been able to see there is no library wind mode for fast forward.

You can still rewind at full speed if you use the zero locater or the auto locater.

Furthermore, RA4 should adjust the tape tension in library wind mode. As far as I can see, the software doesn't switch over to RA4, but stays at RA6, which is the normal rewind tape tension. At least in the software revision I have RA4 doesn't do anything.

So all in all not a very fantastic feature, but it can be used. Probably the reason why it is normally dissabled.

Hope this helps.

Arian.

[C_Campbell]

It's great to see so many resources assembled so quickly here! I know Richard and Eric's sites, but hadn't thought to join the ARSC list, which I will. Fortunately, the tapes I'm working with virtually all have mylar backings, and are in excellent condition; dealing with acetate really doesn't sound like much fun.

Arian, just before I aligned the C270 a couple of days ago, I set that S3 DIP switch to engage the library wind. But I've only played one tape since then, and that only in the forward direction, so maybe I've got library wind already and don't even know it. I'm traveling at the moment, and am now terribly curious to get home and try it out. Still, given that we normally wind tape off to the right, it would seem that a library wind would be most useful in the forward direction, but I guess it might still come in handy. We'll see!

Christopher

[C_Campbell]

Well, last night I decided to sort out this question of a library wind more or less definitively, so I pulled the C270 from its rolling console, removed the rack rails and cage, and studied the DIP switches. Somewhat to my surprise, changing the position of SW 3, the one that supposedly enables/disables library wind, made absolutely no difference in the apparent rewind/fast forward speeds (and I was careful to switch off the power whenever I changed settings so that the system had the opportunity to take account of the switch change). This suggests to me that Arian is correct that the feature was never fully realized. It also suggests that I would only have seen a difference if I had changed the setting of the RA4 potentiometer, but I didn't want to go that far. The tape handling on the C270 is already excellent, and for most of the tapes I'll be digitizing, simply playing them off to the right will be perfectly adequate. Thanks to everyone who chimed in.

Christopher

[ironbut]

Hi Christopher, if you'd be interested in pursuing the library wind issue any further and perhaps find out what would be involved in getting this feature enabled, you should contact Fred Thal. He's the main Studer guy out here on the west coast and I'm sure he's be able to let you know how involved such a conversion would be. He used to run the Studer list and IIRC answered this question for someone not that long ago.
 He is not the guy to talk to about just rigging something up that will kind of work. So if you want this done in the manner that Studer would have, contact him.
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