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Author Topic: Shedding RMG. Is this excessive?  (Read 11198 times)

Offline Tim

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Re: Shedding RMG. Is this excessive?
« Reply #15 on: August 01, 2009, 07:10:17 PM »
  Anyone got the spec on nominal 1/4" tape? You should be able to measure both tape width and guide width.


Nominal guide width:  .252"
Nominal tape width:   .246"
Wiggle room:            .006"

(#s from John French of JRF)

Tape skew (an abnormally strong lateral trust imparted on the tape) can, over time, create a sharp groove on one or more of the tape guides.  These can be effective "tape shredders".

On the same topic, there were some Tandberg models that had an entrance guide that was slightly conical in shape (a deliberate zenith error). The idea was to generate a small downward thrust so that the tape gently hugged the bottom of the tape guides (rather than randomly move up and down within the guide).  This in theory would produce a cleaner and more even wear pattern on the heads. Another Tandberg model instructed you to impart some azimuth error on the scrape filter in order to impart a similar downward thrust onto the tape. If these ideas caused the guide flanges to groove, then I guess it wasn't a good idea. 
« Last Edit: August 02, 2009, 12:09:41 AM by timlein »
Tim Leinbaugh
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Offline dwilawyer

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Re: Shedding RMG. Is this excessive?
« Reply #16 on: August 02, 2009, 08:15:00 PM »
Do you know the age of the tape?  Phil Paske of RMGI has confirmed that there had been problems with curing on some early batches of tape after the move to the factory's present location in the Netherlands...different climate.

If you have a batch number you could contact Phil Paske through the RMGI website.  He was really helpful and informative.

What you are seeing on your white area I refer to as flakeing, and I have not really had any issue of flakeing with TP tape.  After an initial rewind I might git a little, very little, but nothing like what you are seeing there.  One of my TP tapes (Waltz) is putting out a lot of brown residue.  I'm sending it to Paul to take a look at to determine what the cause may be, so we are still in the process of figuring that out.

Travis

Offline dwilawyer

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Re: Shedding RMG. Is this excessive?
« Reply #17 on: August 02, 2009, 08:33:28 PM »
This is what I'm getting from Waltz and Mose.  I will explain what is in the photo:

Starting at the top upper left and moving from left to right, the first 2 swabs are from when I did an initial cleaning of the deck before playing a TP tape.  Prior to cleaning it had more than 10 passes of NOS Ampex 456 through it and the swab on the far left is what I cleaned the heads with and it essentially had no dirt, debris or discoloration of any sort. The one immediately to the right is what I used to clean the tape path, including the tape guides between the heads. There was some gray gook you can see on the end of the swab. This is what I would expect to find after 10 passes of tape, a pretty clean swab from the heads and some dirt in the path, sometimes a bit more sometimes a bit less.

The next three swabs are what I ended up with after 1 pass of the new Mose Allison tape, so to be clear, the third swab from the left is at the top of the photo was from cleaning the tape guides after one pass of Mose, there was little or no residue on the heads. The other two swabs were from cleaning the rest of the tape path and this was more grey in color.

The two swabs on the far right, and this is GOOD NEWS, are from the second pass of the new Mose Allison tape, the basically white swab with NO DIRT OR RESIDUE is from the heads. the brownish one to the right of that is from cleaning the tapes guides and the rest of the tape path. Obviously it is way less then the first pass, and it appears non-existent by the third pass. We will keep monitoring that situation and hopefully we will still keep getting clear passes.

Now kind of the bad news, going to the bottom of the photo, starting on the left again. This is the Waltz for Debbie tape that caused me some concern. This would be the 5th, maybe the 6th pass of this tape.

On the far left is are two swabs I used after I rewound the tape in order to get it ready to play. Swab on far left is nice and clean, as would be expected because in rewind mode the non-moving tape guides are holding the tape away from the heads. On the right is the swab I used to clean the tape guides, note the all brown color, but not too bad really, but way more than I'm used to with 456. The next two swabs are from cleaning after I played both Tape A and Tape B of Waltz. As you can see this is brown in color, the same color as the recording side of the tape The swab on the left is from the heads, the swab on the right is from the tape guides and the rest of the tape path.

I am going to take Paul up on his kind offer and send him the Waltz tape to see if the same thing happens for him, and whether it is even an issue or not.

It may not be, again I don't know. What started this whole thing off is that I'm used to NOS Ampex, and seeing very little in the way of dirt or residue after 10, 15 even 20 passes of tapes as reflected in the two swabs in the upper left hand portion of the photo. Any of other swabs in the photo, as compared to those two look bad, at least to me, but it doesn't mean there is a problem, but there could be. 

Paul posted in the Tape Trail forum that they were getting zero residue after each recording at the tape recordinng facility which really got me thinking because, as you can obviously see from the photos, there is obviously more than zero residue after 4 or 5 passes. By the way, I cleaned the heads and tapes path to the point where I was getting perfectly clean cotton swabs before moving on to the next test. I just photographed the first two or three swabs to reflect what residue I was getting.

As far as the Mose, I don't think it is going to really be an issue, just a bit more initial residue than I am used to, but it looks like that is disappearing fast.

Hope this helps anyone out there that might run into a issue similar as this.

Travis