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Author Topic: Lawson's Show No Mercy RMGI LPR-35 Test  (Read 7645 times)

Offline Lance Lawson

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Lawson's Show No Mercy RMGI LPR-35 Test
« on: July 19, 2011, 08:12:55 PM »
At last I saw clear to run some tests on RMGI?s LPR-35.  The recent threads concerning some issues with it did indeed prompt me to run this test.  Now before I go into the test itself I will say that I have had an uneasy relationship with RMGI tape since my first purchases of it in 2009.  But that is water under the bridge at this point.

For the test I used a 5? reel with just under 300? feet spooled onto it.  This gives an actual test length of 600? for recording but as the tape is always being run through the transport all the tracks receive wear whether the tape is in record mode or not.  Leader was attached to both ends and for the most part the tape was recorded from side A to side B without rewinding but the recordings were monitored off of the heads as the recordings were made.  I used a variety of CD?s of various genres as a means to determine the character of the tape.  Sometimes the tape was stopped and playback was carefully listened to for quality and flaws.   I found that running the tape through three cycles of recording both sides was about the limit of my concentration to actually listen critically to the results.  So when I felt ear fatigue was setting in I took a break.  Whenever I went back and listened to the last playback the tape always sounded better than when I broke for rest but this is expected.

For the test I used my TEAC A-2300SD.  The machine was cleaned and demagnetized before starting the test.  Speed was set at 7.5ips and Dolby was engaged.  Both bias and EQ switches were set in the #1 positions.  A white piece of paper was placed below the transport to show up any shed or shaving particles.  Listening was done through Sennheiser HD 280 headphones.

The tape itself is a typical back coated type that is a deep rusty brown in color on the head side and a matt black on the backside.  Noticeable to me was the thinness of the LPR-35 as its 1 mil thick.  I?ve been working with 1.5 mil thick Ampex and RMGI for two years now.  When handling 1 mil tape it pays to be mindful that it?s much easier to damage it than its thicker counterparts.

The testing schedule went as follows.

Friday 7/1/11:  Five full passes of recording were achieved and one dedicated listening pass at the end of the fifth pass.  This totaled 3000? of tape travel.  Recorded music was Dion?s Son of Skip James.  All five recording passes were perfect.  Peak db was allowed to go as high as +4db without distortion of any type.  Upon dedicated listen pass the tape was confirmed to have recorded perfectly.  At session?s end the heads and transport were cleaned and showed what was minor and typical tape deposits.  There was no particle shedding and no edge shaving observed at all.

Saturday 7/2/11:  Taping began with Goo Goo Dolls Dizzy Up The Girl.  Specifically the tracks Slide, Broadway and Black Balloon.  This was followed by Marshall Crenshaw?s  Marshall Crenshaw CD and the tracks Cynical Girl, There She Goes and Rockin Around In NYC.  Next was Gin Blossoms New Miserable Experience and the tracks Lost Horizons, Hey Jealousy and Allison Road.  These selections were chosen for the bright jangley nature of the music. The recordings were and monitored directly off the heads in real time.  This amounted to 5,400? of tape travel through the transport for a total of 8,400? of tape travel.   The response and performance of the tape was perfect throughout and captured all of the intended  brightness of the selected tracks.  The heads and transport were swabbed with denatured alcohol using the same swab as I used in the beginning of the test.  Oxide and tape particulates were nil.  Overall impression was very positive in all respects.

Saturday 7/2/11 Second Session:  Anita Baker?s Rapture CD was chosen and was run without specifically selecting tracks due to the very ?signature? sound of this CD.   Next came Bruce Hornsby?s Hot House and the tracks Spider Fingers, Tango King and Hot House were chosen.  From there I  went to Patty Griffins Flaming Red and the tracks Mary, Tony and Peter Pan..  All selections were run through 3 recording passes.   These selections have a smooth rich texture with abundant little sonic details.  By sessions end the tape had acquired another 5,400? of travel for a total of 13,800 of travel and still no discernible drop off in sound quality and still no dropouts or physical signs of tape wear/failure.  I had the distinct impression that I could have continued the tests further with continued success but I sensed that it would be pointless at this stage.  So I prepared to conclude the test.

Sunday 7/3/11:  I used for the final session 3 selections of my own original music.  These tracks are mixed very brightly and feature lots of acoustic guitar.  I Degaussed the heads again and cleaned the transport.  Then I rolled tape.  The LPR-35 performed flawlessly and was still able to capture the intended brightness of  these tracks.  These recordings were taken directly off of the 96/24 SONAR digital master tracks and represent the most detailed and brightest recordings of the test which is why I saved them for last.  If anything the transfer to tape achieved the desirable effects of tape compression and analog warmth  while retaining the detail of the digital masters.   I was impressed, very impressed..

Now I had intended to make a lot more passes over this reel of tape and I may yet.  However I realized mid way through that I was running my TEAC harder than I?d ever run it before.    More importantly though I had run the RMGI LPR-35 harder than any tape I?d ever run.  While my intent was to run this reel to death it became clear as the test went on that I perhaps would have run my TEAC to death before making the tape quit.  The tape didn?t quit nor did it exhibit any weaknesses.

If I am to compare RMGI LPR-35 to the tapes I used when my TEAC was new I can say that it exceeds them all, some by a very wide margin too.  Granted that this is only a short section of a large pancake of tape but the potential is outstanding and I?ve reason to believe that the rest of the tape is as perfect as this section.  There for me only remains now the question of longevity.  But my LPR-35 seems to run clean, in fact cleaner than Ampex Grand Master that I used regularly when it was current.  So at last I think I?ve come home and will have my venerable A-2300SD  biased to accept LPR-35.  I have a pancake of ATR on the way but somehow I don?t think I?ll require it except as a the option of having choice.  But I firmly believe that at least on my TEAC the LPR-35 is going to be a tough act to follow.




Offline ironbut

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Re: Lawson's Show No Mercy RMGI LPR-35 Test
« Reply #1 on: July 19, 2011, 11:14:33 PM »
Nice post Lance.

Maybe it's just me, but if time allows, I like to make "real world" tests like this with a tape I'm not experienced with.
You should be aware that there are some drawbacks to LPR-35 that may not be so obvious (you may already know this but others reading this thread may not).

I would like to say that I use this tape myself for some things given it's longer play time at a given speed. In fact, I was jazzed that RMGI chose to make a 1 mil tape.

The issues involved with this tape are associated with it's thinner backing (as mentioned, it's on 1 mil as opposed to 1.5 mil like all the other currently manufactured tape is backed with).

The first is the lower tensile strength of the thinner backing. If your machine is gentle with tapes, just a little more care can make this a moot point.
Doing things like jogging from fast wind to the opposite direction fast wind to slow the reel speed before engaging stop (and the braking) helps a great deal.
Also, using plenty of leader will keep the part of the tape with the program material on the reel during starts and stops.

The second concern I would have is the increased print through.
 Magnetic forces decrease quickly with distance. This can be easily demonstrated by adding pieces of paper between a fridge magnet and the fridge. Depending on the strength of the magnet, you'll get to the point where another piece of paper will make the magnet slide down the fridge. Of course this is a combination of the weight of the paper but if you now cut the papers to 1/4 of the their original size, you'll find that it doesn't take many more pieces to make the magnet slide again.
It's the same with the backing of the tape. Even that 0.5 mil makes a big difference when you're talking about the level of magnetic force the particles of oxide on the tape have after recording.

Once again, you can minimize print through. The main thing is to "exercise" the tape within the first couple of hours of recording. These first hours are a period where the charges and the barriers that isolate these charges haven't stabilized.
So if you wind the tape during this period you shift the layers and the energy is distributed rather than focused on one spot. This doesn't actually "stop" the transfer of energy from one layer to another, but it keeps it's results from being as audible.
Periodic playing also helps. Even though the forces are much more stable, the layers are in the same places for long periods of time. Playing shifts their orientation.
Also, reducing these energy levels helps but you probably don't want to suffer the increase in the noise floor.

There's more info on print through in the Beginners Guide but it gets pretty technical (I had to read the AES papers a gazillion times to get a handle on what's going on with this stuff!).

So, like I said at the beginning, these may be issues you're aware of but I wanted to point out the "cons" to those who are unaware of them.
« Last Edit: July 20, 2011, 09:54:32 AM by ironbut »
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Offline Lance Lawson

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Re: Lawson's Show No Mercy RMGI LPR-35 Test
« Reply #2 on: July 20, 2011, 05:46:43 AM »
Ironbut very interesting concerning the exercising of the tape and the effects it has on the signal early on.  Nearly all of the tape I've used since the mid 70's has been 1.5 mil thick.    Handling the 1mil LPR-35 required being mindful of it's thinness.  Print through I've found is no worse than any other backcoated tape and at least on my machine is on par with the RMGI 468 I have. 

Not long ago I experienced major coating failure on some older 1mil  tape.  Its true that the thicker tapes are more robust across the board.  But I too am glad RMGI came out with LPR-35 as it seems to track perfectly in my TEAC which is something the 468 wouldn't due due to due to the slitting width.

Offline billt75

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Re: Lawson's Show No Mercy RMGI LPR-35 Test
« Reply #3 on: April 03, 2012, 12:32:38 PM »
Lance:

I enjoyed your comments about the RMGI LPR35.  Have you ever done any recording with ATR Magnetics offering?  I just had my deck (Tandberg 10XD) gone over and I'm looking into getting some new tape.  It seems that RMGI & ATR are the only options.  Any information is appreciated.

Best Regards,

Bill