Questions about Tascam 44-OB 4 track reel to reel

[Arjan P]

@SkywaveTDR I hope you realize you are stretching the friendliness of this forum by talking about vaccines, big pharma, Bill Gates and so on. Please keep that stuff out of here. It is simply not the place - no matter how anyone feels about what is true or not.

 

[SkywaveTDR]

Taken care of.

 

[Mark Richards]

...I've gotten a new 10.5 Ampex 456 which sounds good and doesn't seem to be shedding.

Caveat emptor. When was the 456 tape manufactured?

Ampex 456 tape manufactured during the late '70s into the late '80s suffered from moisture buildup between the tape layers during storage, causing the layers to stick together. The problems have been reported also on 406/407, 457, and 20:20/373 tape

Within 7 years of the manufacture date, even if stored in a controlled environment, Ampex tape from that time period became unusable (Sticky Shed Syndrome - SSS) and could, potentially, ruin tape heads, as well as tape fidelity, if played.

In response to this problem, experiments by Ampex resulted in a 1989 patented process (now held by Quantegy) to restore the tape temporarily by baking it. The dry heat of baking removes the moisture and reconditions the tape. Ampex found that baked tape would remain playable for up to four months, after which it will revert to SSS.

Although Ampex also found that an SSS tape could be baked multiple times without further degradation, baking should only be used to restore the tape so the contents can be transferred to other media.

Perhaps in the long run the more prudent thing would be to not use such tape in the first place unless you're sure the manufacture date is post 1980s; or the recorded material is of only a temporary nature.

 

[SkywaveTDR]

At Teac we had no occasions of sticky tape either in shop or by customers even up to 1987 and the wrong binder that came from an Indian guy was used in the manufacture after 1990. Tapes earlier than that were never heard of being sticky. Tape can never ruin tape heads- you are reading wives tales again. I have never seen a tape ever ruin a head except for wear that is normal.

 

[Mark Richards]

I wrote"potentially ruin". Ahhhh.

I should have been more precise (and more precise still - edited for clarity):

"Following a period of storage over a number of years, the magnetic coating becomes physically stuck to the back-coating of the tape layer above it. The magnetic oxide on the layer below becomes so sticky from the bonding agent that, when played, it sheds a thick layer of magnetic oxide and gunk in the entire tape path to the point that the take-up reel can't pull the tape onto it and the deck freezes. It takes a diligent effort to clean the gunk off the heads and tape path; and if you're lucky enough, with even more effort, you'll get all the gunk out of the head gap too".​

That was my personal horror story with Ampex 456 tape manufactured in the '80s and played back 10 years and more later.

But I opted not to be so wordy since the Ampex patent I made a link to describes the issue in detail. My bad.

SSS (Sticky Shed Syndrome) was of sufficient concern by the late '80s that Ampex started looking for a fix in '88 and made a priority patent application with the "fix" in March 1989. The patent states in part:

"Some magnetic tapes deteriorate slowly over a number of years, and eventually exhibit the undesirable properties of stickiness and excessive shed of the magnetic oxide coating layer. These properties usually prevent the use of the tapes in equipment for recording or playback. Magnetic tapes currently in use have exhibited these undesirable properties within 7 years of their manufacture."
(see my link to the patent in post #43).​

SSS has been an issue with professional grade back-coated tape manufactured between the late '70s and late '80s (primarily Ampex and 3M/Scotch - Japanese and European brands didn't have the problem, as I recall. Thus apparently the qualification "some" in the patent language).

In my commercial recording studio, we used only Ampex 456 Grand Master in the '80s and stored the reels in a controlled environment.

In the '90s, when we started transferring those masters to digital, every one of them had contracted SSS, failed, and required baking using Ampex's patented process to recover the music.

Maybe we alone were just very unlucky with the 456 pancakes we purchased over the course of time back in the '80s, but I doubt it.

 

[-mjk-]

My 1981 mix master tape broke in 1987. It stuck to the heads and that was that.

 

[SkywaveTDR]

OK, Different experiences I guess. Sony was the only company of the Japan origin to also go with the Indian guys cheaper binder. The idea that the problem is due to back coating is always assumed simply because the bad binder was used only with better tape that had back coating. This does not mean that the back coating was the cause and there was some guy charging money to take the back coat off as if that was going to solve the problem but it must be understood that the binder failure is on the oxide side as the tape would not be stopped at the heads if the back coating was the only fault- again people jumping to conclusions without knowing what is really going on.
I had some Scotch 807 that was never before played- it was new tape- it would not play for 5 minutes. A guy posted on a Forum to use Nu Finish to treat the tape and so I said I will see if he is full of crap which a lot of Forum information is. So I treated the tape and the tape at the end of the cleaning and with a clean tape path played all the way through the tape without an issue. This was all the proof I needed. Now I had a roll of Ampex 478 that was oily and could not be resolved but that was a different issue I am thinking. I am not a tape baker and I think that is a waste of energy as I have seen tapes at Moody Radio revert back inside of a few hours. The people baking the tape did not understand what they were doing with it and let it sit in a cooler for too long and I would tell them but do they listen- no.

 

[-mjk-]

I used Ampex, Scotch and AGFA 2" over the years. They all would soak up humidity from the air and get sticky.

Check out this video at 0:29:

Brian May talks about baking the 2" for Bohemian Rhapsody and he even showed the sticker "Baked at Harrisons" so they could run it on the 2" one last time and dub to digital. Baking is kind of an art and yes, the tape goes back to the way it was as it absorbs moisture from the air (but I wonder whether a sealed container with desiccant would prevent that). Each time you would want to play an old master tape, it would require inspection to determine if it needed re-baking prior to playback.

Once (in the Boston area) there was a bad batch of AGFA that shed like a dog. AGFA tended to shred more than the others anyway, but it sure did sound great.

In that video, the 2" is Scotch. In the movie, they show a re-creation of the recording session using a 3M M-79 2" multitrack. I have personally done something like 200 sessions on an M-79 and a high number of those sessions were using Scotch tape. That is probably the fastest punch-in machine ever made.

 

[Mark Richards]

...The idea that the problem is due to back coating is always assumed simply because the bad binder was used only with better tape that had back coating. This does not mean that the back coating was the cause... it must be understood that the binder failure is on the oxide side as the tape...

The Ampex patent confirms SkywaveTDR's observation that the problem is in the magnetic oxide binder of tapes that have a back-coating.

Synopsis:

" Magnetic recording tape comprises a metal oxide, on a base film that usually also has a back coat on the opposite side of the base film"

"The [resin binders and other] materials contained in the magnetic coating of current tape are susceptible to exudation over time"

"The [magnetic coating] binder can exude from the coating causing the tape to be sticky and to shed the magnetic oxide coating from the base film during recording or playback"

"When the magnetic coating is released from the base film while in use, it collects on the recording and playback heads in the equipment as well as other components along the tape path, and can clog the heads and also impede the transport of the tape"​

While this may be getting into super geeky stuff, I edited my Post #45 to clarify this.

All that really matters is that back-coated Ampex 406/407 and 456/457 (and similar 3M/Scotch tapes) manufactured between the late '70s and late '80s very likely already have the SSS problem or will develop it in due course.

SSS applies to all sizes and mils - 1/4" through 2" tape.

 

[SkywaveTDR]

Well I do not bake tapes. I do not use 2" tape either. I did have a deck come in that had $800 of motors replaced but it did not fix the problem which was sticky tape. Some technicians they have that don't even know about sticky tape.
Anyway I had an Ampex 1" tape sitting around that was sticky- I processed it with Nu Finish and this tape then played again. The idea of baking is the chasing out of the moisture of the oxide layer but also chemical processes can do this as well if not better and faster such as alcohol. The black residue that I have seen on heads and lifters does not match the color of the oxide at all so it is a material that is used and is now surfacing to the top layer of the oxide to be deposited on the lifter. I have never analyzed it but it has been called a combination of binder and water from the air which makes better sense than it being oxide itself. In the tapes I have seen the oxide always remained on the base layer as oxide coming off the base would be total binder failure and there is no hope to repair that. The Nu Finish product is one that not only chases off the moisture and I looked into what it had in it that could do this- there is a substance that is called Stoddard Solvent and to me I have never heard of that but I assume it has a way to chase off moisture. Name not being important as function the solvent chases off water and then the Surfactant in the polish seals the tape from further moisture exposure. The sealing is the important part as baking does not do that. So for proof and I am always one to make mention of stuff that is either snake oil or other outright lies, I processed a old Alignment tape that was still good but there were areas of it that would squeal. I can only assume it was Ampex 406 as it was 1.5 mil tape and not likely 456 or GP9. Well alignment tapes are easy to process as they are usually short- I did measure output from the tape previous to doing this so I had found that the resultant treatment did work and the levels did not change. In fact I still have that tape on a bench and it has most likely gone through 100 passes again that most home tapes will never see.
Further- my use of Nu Finish was also used in polishing heads that had some surface marks- or oxidation. This Surfactant in the mix also has the characteristic to provide better tape to head contact in that on a Tascam 42 that has 1 dB variation on it went down to 1/2dB variation after the head was polished with Nu Finish. I use it all the time now to ready a cassette decks head for alignment and it helps with frequency response and tape travel across the head. My only connection to the Nu Finish product is that when I worked at ESPN in the Hancock building on the 15th floor the Reed Union company was located on the 14th floor which I never discovered until many years after I did not work there. They were the makers of Nu Finish Polish- you must use the polish in the orange bottle not a vinyl product.

 

[bobyoung53]

Lima, Peru where I now live tends to be very humid in the winter with average temperatures at night in the high 50's, low 60's, most places here don't have heat as you really don't need it. It dries up in summer, we're in early spring now (seasons are opposite) and it is getting drier now, the Ampeg 456 tape I was given seems to be functioning much better. He also gave me another one which sounded good right out of the box (it was NOS), I'm not sure if the lessening humidity here has anything to do with the tapes playing better or if it's just because I tried to clean the heads thoroughly. I also have no idea how old the tapes are.
The remaining problem I have with the bad 456 is that channel 1 has a little less volume and exhibits an occasional dropout. To be on the safe side though I just bought three pancakes of ATR and will stick with new tape.
One more question, I bought 1.5 mil tape 2500 ft, I assume that's better than the 1 mil 3600 ft tape?

 

[Mark Richards]

Bob, tape should be recorded, played and stored tails-out to minimize print-through during storage (scroll down to Quality Aspects, 3rd para).

The thicker 1.5 mil tape will help minimize print-through too; and help also to better minimize the possibility of tape stretch.

But the primary reason for using 1.0 mil tape is longer recording time.

 

[bsigman]

The relays have been a problem in all Tascam decks and they said it was a nicked coil in manufacturing but there have been a lot of nicked coils out there from Omron. The way you test them is with an ohm meter measuring the coil which is pin 2 and 6. I seem to remember they measure like 1500 ohms. If 2 and 6 measure infinite then the coil is open. There were some cheaper Hamlin relays but to date I have used Coto relays. Yes each card is a separate channel and so 4 relays in 44 and 8 relays in 48, The RCA are also muted by a relay but it is a single pole relay. The coil is in the same pins. I cut leads off a AMP type IC socket so there are two at each end then these sockets go into the board and can then take the relay. The relay number is 8L02-24-00 and they are from either Mouser or Digikey. https://www.mouser.com/ProductDetail/Coto-Technology/8L02-24-00?qs=/ha2pyFaduik2xApWQvfrnLDuxkyhrApJ%2BZFj%2Blc3I8=

The double pole relay can be used in single pole (RCA) position but a single pole can not be used for the XLR which requires two poles. If you see Markon 100uFd or 220uFd caps it would be good to change those for the same value in Nichicon, Wurth or Panasonic FM 105*C caps. The Marcons have not been aging well and a bunch have shorted in 48 and Z6000 where used,

SkyWave. Would you remember the AMP Type IC socket part number from Mouser by any chance? I have a 44 OB that someone wire across the mute relays on all 4 boards. I have ordered the Coto reed relays and want to put them in the IC sockets but I don't know enough about the AMP sockets to get the right ones. I suppose the pins you are talking about cutting off the socket are the ones that aren't used (no holes there) . I have 3 other tascam/teck 4 chanel units to work on after I bring back the 44 OB to life. Thanks so much for all your posts. They are amazingly helpful to US! bsigman@cfl.rr.com

 

[SkywaveTDR]

Well most the AMP 14 pin IC socket will work. It would appear that AMP does not sell sockets at Mouser anymore or maybe they stopped making them. This is a socket I have used-
https://www.allelectronics.com/item/ics-14/14-pin-ic-socket/1.html

The best sockets are machine pin sockets as they really hold the IC in but I have never had a IC or relay come out of any socket I put in. Unicorn electronics has the good price on Machine pin sockets. They cost more but are the high grade stuff- I have these in stock too and I think they are gold plated as well.
https://www.unicornelectronics.com/icsockets/MT8.html