Tape Project Forum

General Category => Raw Tape => Topic started by: Lance Lawson on July 30, 2009, 03:26:21 PM

Title: Shedding RMG. Is this excessive?
Post by: Lance Lawson on July 30, 2009, 03:26:21 PM
I've been running lots of test on my new RMG 468 and overall I like the sound.  However I set the machine up so that it would be on a white surface where shedding particles would show up easier.  What appears in the photo is about 2/3 of the total amount of shedding as I cleaned away the early accumulation.  I've run the tape about 20 times an re recorded over the 1st half of the 1st side about 10 times.  Recording on the heavily used section is getting poor but the lightly used sections sound fine.  The second side is un recorded on having just wiped the first side I'm planning to record on the second side.  In any event the amount of shed I feel is excessive but its been years since I've seriously worked with tape.  Any opinions?  Thanks!

Title: Re: Shedding RMG. Is this excessive?
Post by: docb on July 30, 2009, 04:19:39 PM
It can be tough to say whether this is due to the machine or the tape itself. From the photo it looks like maybe the residue on the paper is falling down from the take up side swing arm guide. Are you seeing buildup on other areas too? Can you see any wear on the tape surface itself? If the shedding is all falling off the machine from one specific location in the tape path and not accumulating on the heads or guides much it might be that something at that point in the tape path is scraping it.

Also, have you tried other reels of 468? I have yet to come across a reel that leaves anything on my Nagra after a single pass. The duping machines at the studio are cleaned after each and every pass, and they show little or no buildup at all. On the other hand we have heard from a couple of subscribers that they are seeing some buildup on their machines. I don't know whether it has been established in those cases whether it was the individual tape or the machine or if perhaps humidity is a factor.
Title: Re: Shedding RMG. Is this excessive?
Post by: Lance Lawson on July 30, 2009, 05:07:16 PM
Most of the shed is at the swing arm but I did concentrate the shed into that local area.  But there has been a general deposit below the entire length of the working area of the tape.  That is to say from  feed reel swing arm through the heads and take up swing arm.  Some of the shed consists of long strand like material as opposed to random dust although there is random dust like shed particles also.  Virtuall alll of the tape used on this machine during the time I frequently used it from new to early 1980's was Ampex and BASF.  I'm thinking that perhaps the RMG is a bit wider than those early tapes I used.  Other than this I'm pleased with the RMG.
Title: Re: Shedding RMG. Is this excessive?
Post by: docb on July 30, 2009, 05:29:20 PM
Hmmm, that long strand sounds like the tape is being shaved. We see that sometimes on RS1500s when the top set of fixed guides is off center with the tape path. From your photo it doesn't looks like the rounded edges of the swing arm guide would cause it. I'm feeling a little dumb as I don't recognize what machine this is. At least I can blame the heat - only 91 today, after 101 yesterday - are there maybe fixed guides with sharper edges near the heads?
Title: Re: Shedding RMG. Is this excessive?
Post by: steveidosound on July 30, 2009, 05:38:45 PM
It is a top down shot of a Teac/Tascam of some vintage, and I would say yes, you have something that is scraping or there is an issue with this reel. 10 times past the heads, or even 20 for record /playback should not make the quality go down in any real or gross way. The first thing that could degrade quality would be oxide buildup on the heads (restored by cleaning) - not the tape wearing out. And if there is an issue with the tape itself across the width, it will be there when you flip the tape and record the other side, unless the issue is with the gaps or something inline with the just the tracks themselves scraping off oxide, which should not happen.
Title: Re: Shedding RMG. Is this excessive?
Post by: astrotoy on July 30, 2009, 06:15:39 PM
In addition to the 10 TP tapes, I have purchased 40 of the RMGI SM468 pancakes from TP (made from the excess tape of the TP issues). I have recorded vinyl to tape on all of them. I have used my Bottlehead modified Technics RS1506 to play tapes, and my Otari MX5050 B3 and Ampex (made by Teac) ATR-700 to record them. I haven't had any problem with the shedding issues that you have. I have treated all my TP tapes and some of the pancake tapes with LAST tape preservative. What I do get on the applicator after treating a reel with LAST is a little brown coloration - from some of the oxide coming from the tape. Given that somewhere on the order of 2000 feet is passing through the applicator (a spongy material on a plastic stick which holds the LAST fluid) it certainly is not much material coming off. I also get a little coloration on my cotton swab after playing a tape, the swab is slightly darkened but no particles of any kind show up on the swab. There are no sticky sheds or droppings that you can see on the picture taken by Lance. I put the applicator right next to the right hand reel while rewinding - so no part of the tape path comes in contact with the tape before it hits the applicator. I don't hear any degradation in the sound - even with some of the TP tapes that I have played a dozen times. Larry
Title: Re: Shedding RMG. Is this excessive?
Post by: ironbut on July 30, 2009, 06:43:44 PM
If you're getting tape curls than something is definitely off on the tape path adjustments. Until you find whatever the tape is being trimmed by, you'll really have a hard time telling if the shed is related (which I'd figure it is) or is a different problem like with the tape itself.
Like Doc said, it's almost always a guide that is either out of adjustment or sometimes the inner corner will get a bit of something stuck in it forcing the tape toward the other side. These bits will snowball into larger bits sometimes. A severely worn head can do this too and if your machine has glass heads, those can chip instead of wear causing sharp spots.
But most likely, it's something out of adjustment. One reason it could seem like it's the tape is the other tapes that you've played regularly have already had their edges trimmed off. If the adjustment is off due to normal wear, this would've happened gradually to your tapes and until you played a tape that was "full width" you wouldn't notice.
I'd start by "getting in there" with a good light and a magnifier to look in those corners first, than any rolling part that might have slop in the bearing, and also tiny shinny lines polished by the edge of the tape.

Of course, there is the possibility that a batch of tapes got out of the factory with poor slitting but that's pretty unlikely. The Europeans used to point out their superior slitting to US tapes. The lack of outer flanges on even very large reels is pointed out some evidence of this.
Title: Re: Shedding RMG. Is this excessive?
Post by: Lance Lawson on July 30, 2009, 06:55:59 PM
Hmmm, that long strand sounds like the tape is being shaved. We see that sometimes on RS1500s when the top set of fixed guides is off center with the tape path. From your photo it doesn't looks like the rounded edges of the swing arm guide would cause it. I'm feeling a little dumb as I don't recognize what machine this is. At least I can blame the heat - only 91 today, after 101 yesterday - are there maybe fixed guides with sharper edges near the heads?

The machine is my TEAC A-2300 SD.  While there is a "moderate" amount of time on this machine the heads and general transport are in excellent condition.  BTW when I began using the deck again I was running a BASF tape and there were no shedding issues at all just normal oxide residue.  My prerecorded in 1979 Memorex Blonde On Blonde tape runs through perfectly.  I suspect I have a "wide" tape with this batch of RMG.  I'm about to run the second side so we'll see what happens then.
Title: Re: Shedding RMG. Is this excessive?
Post by: Lance Lawson on July 30, 2009, 08:51:06 PM
Before starting the second side of the tape I cleaned the heads, tape guides and capstan of all deposits.  The recording time on the second side consists of 4 takes of a 3 minute song and I estimate the tape ran nonstop for 15 minutes.  Recording quality was fine.  After listening to the playbacks I cleaned the heads and guides again and while cleaning the swing arm on the take up side I did remove this rather large piece of debris.  Also the rest of the Qtip is fairly brown.  I took these photos of the Qtip and the pile of shedding from the recordings just made.  The previous shedding was removed so what is visible is from the recording time stated above.  I'm debating sending the two unused tapes back and trying ATR.  IMO I seem to have gotten a bad batch, or worse.
Title: Re: Shedding RMG. Is this excessive?
Post by: docb on July 30, 2009, 09:17:08 PM
I'm not sure if this is some of our scrap tape that you purchased or if you have purchased new tape from a jobber. If it's scrap from us send it back and we will be happy to refund your money. If it's not scrap from us I guess the next thing to do would be to take the issue up with RMGI or the distributor you bought it from. There's not much we can do in that case beyond sharing our own experience, which has been quite positive.
Title: Re: Shedding RMG. Is this excessive?
Post by: Lance Lawson on July 30, 2009, 09:40:04 PM
I'm not sure if this is some of our scrap tape that you purchased or if you have purchased new tape from a jobber. If it's scrap from us send it back and we will be happy to refund your money. If it's not scrap from us I guess the next thing to do would be to take the issue up with RMGI or the distributor you bought it from. There's not much we can do in that case beyond sharing our own experience, which has been quite positive.

I purchased the tape from Full Compass Systems.  I've dealt with them many times for many things and they are a first rate outfit.  I haven't approached them about it yet but I'm confident that they'll refund or exchange the unused tape. 

I wonder is baking the tape would help?
Title: Re: Shedding RMG. Is this excessive?
Post by: docb on July 30, 2009, 09:57:07 PM
At this point I suppose it couldn't hurt. But my impression is that baking is intended more for trying to get one clean pass out of a tape for transfer than it is assumed to be a long term solution. I haven't found a correlation between tape shaving and shedding myself, so I can't offer any insight into whether or not it would also help with the shaving issue. Maybe the guys at Full Compass will have some feedback from other customers about  the batch that your tape came from.
Title: Re: Shedding RMG. Is this excessive?
Post by: ironbut on July 30, 2009, 10:13:28 PM
Baking tapes only helps in the case of hydrolysis often called Sticky Shed Syndrome. I believe you experienced this with those old Ampex tapes that you said were unplayable. Sticky shed was an unfortunate result of a change of the binder of many tape formulas. I'll spare you the technical mumbo jumbo although if you wish to learn more there's a section on it in the "Beginners Guide" at the top of the General forum. Having read your accounts of the unfortunate end of some of your old tapes and having some first hand experience with it led me to suggest "checking the corners"  in my post above.
What happens with SSS is over the years (often decades) water combines with the glue (the binder) that attaches the oxide to the backing of the tape. It changes it into an almost tarry substance and usually the first sign of this contamination on the tape path is squealing. The squealing is caused by vibrations of the tape as it crosses the sticky contaminant that's now securely stuck to your tape path, just like the rosin on a violin bow. Sometimes this doesn't happen and without prior warning, the contaminant can stop the machine dead in it's tracks.
This contaminant is really tough to remove. Usually just alcohol will take forever to remove even a pin point bit of this stuff. I use Lazormedia head cleaner which I believe contains Naptha so you can just use the real stuff. Unfortunately instead of the few minutes that it takes to normally clean the tape path, this usually takes closer to 30 minutes because you need to get into the corners of everything that the tape came in contact with (with some guides, dental floss is one of the only ways to get in there).
One of the reasons that this stuff only rears it's ugly head when playing the tape is it's loosened by the the heat created by friction. It also tends to collect in the inside corners of guides. Usually it collects in tiny clumps that are hard to see with the naked eye but it can also spread out and cover an entire surface.

I have a tape that has SSS that I keep in a plastic bag with silica gel all the time. It was still sealed when I bought it a few years ago and developed SSS after about a year. I keep it in that bag because I love the music and sonics and about once a year I can take it out and get a few plays out of it before it starts squealing. But when it does, I know I have a pains taking chore ahead of me. The first time I had to clean SSS contaminant off my machine it took about 5 times before I got it all.

I'm not sure if this is what the problem is, but since you tried several of your old Grand Master tapes that you said had "breakdown" since you've revived your Teac, the odds are pretty good that it may be a contributor.

Hope this helps.
Title: Re: Shedding RMG. Is this excessive?
Post by: Lance Lawson on July 30, 2009, 11:24:12 PM
Thanks everyone.  Interesting about sticky shed stopping a machine dead.  It did this on my TEAC and the mess on the heads and guides was a task to remove. 

I took all the shedding particles and dropped them into an alcohol bath and they didn't dissolve.  More than anything else they look like shavings.  Some of the larger ones have a sheen not unlike the working surface of the tape itself.  I watched the take up reel swing arm carefully as the tape played through and every now and then it "judders" and pulses.  It'll run that way for maybe 20 seconds then it steadies again.  So it seems that the take up swing arm has a tight edged groove. 
Title: Re: Shedding RMG. Is this excessive?
Post by: steveidosound on July 31, 2009, 12:49:23 AM
This comes under the heading of rumor more than fact, but I have been told that there was an issue with the guide machining on some earlier Teac machines. I suppose it could just be a case of absolute minimum width tolerance limit on your guide and the tape slit to the absolute maximum width tolerable. Anyone got the spec on nominal 1/4" tape? You should be able to measure both tape width and guide width.
Perhaps the guide is narrow in one spot where the tape wraps around and could be physically turned to a different contact surface that has a slightly wider gap.
Title: Re: Shedding RMG. Is this excessive?
Post by: Tim 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. 
Title: Re: Shedding RMG. Is this excessive?
Post by: dwilawyer 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
Title: Re: Shedding RMG. Is this excessive?
Post by: dwilawyer 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