TSR-8 signal decreasing over time

[soul]

Hey all,

I'm back with a new issue on my TSR-8.

I am transferring 3-minute songs from Pro Tools. After about 90 seconds, one of the tracks (7) decreases in level a few dB. It's happening at around the same time (after recording 90 seconds or so).

What could cause this from happening?

Thanks,
Steve

 

[soul]

Here's a screenshot of the waveform when I bring it back into pro tools from the TSR8

https://drive.google.com/file/d/1FYprEmsebX7J5uz8bQanuQfCYyou-HT9/view?usp=sharing

 

[soul]

Ok little more investigation today.... I thoroughly cleaned all of the guides and that may have been contributing to the decreasing level over time. There was a considerable amount of buildup on them.

On a new pass, I don't notice it nearly as much

 

[BRDTS]

Yeah, whenever I use my two synchronized tsr8s for any length of time (not so much the 1" and 2" machines), I'll stop every three hours or so, power off, remove the reels, clean and demag the heads/path, take a break, restart.

It's just always seemed to me that the smaller quarter-inch & half-inch machines around here get gunked up sooner than the bigger machines (ambient temps can play a part) and for sure, the moment I detect fuzziness or decreased high end/ level, it's time for the cleaning break.

 

[SkywaveTDR]

It is something of a observation thing. Does oxide pile up on the single track or does it spread across several? Tape that is being shaved will go on several tracks- pull some 1/2 inch sandpaper through the stationary guides to remove edges that are sharp enough to shave tape- usually the worse edges are at the outer edges. This is a maintenance issue but if you do not have it worked on by a professional then you need to do the same thing. The other issue is pole pieces sticking up shaving oxide. This is harder to fight with- I sent a head to JRF to have lapped and it did the same when it came back. Pole pieces wear slower than the surrounding material and if they stick up they will for only that track pile oxide up on only that track and cause it to decay in response and I have sen it happen. It seems like maybe NU Finish Car polish might help with the lubrication surfactant it has in it- make the tape slide across heads better. Otherwise new head is in line. It is more economical to see if stationary guides have edges or sharp spots before changing a head.
OH, The sandpaper I cut to larger than 1/2 inch so that it wraps up and takes care of the side cuts is 400 or 600 grit not 100. The TSR8 is a low cost machine and why it does not have ceramic guides on it like the higher up Otari decks have. If you have machinist ability or know someone you can have them made- ceramic is harder than glass and is only bettered by Zirconium and Diamond.

 

[soul]

Yeah, whenever I use my two synchronized tsr8s for any length of time (not so much the 1" and 2" machines), I'll stop every three hours or so, power off, remove the reels, clean and demag the heads/path, take a break, restart.

It's just always seemed to me that the smaller quarter-inch & half-inch machines around here get gunked up sooner than the bigger machines (ambient temps can play a part) and for sure, the moment I detect fuzziness or decreased high end/ level, it's time for the cleaning break.

Thanks, BRDTS! I'm now cleaning heads and guides between each pass back and forth between Pro Tools and the TSR8. Any concern over cleaning them too often? Like does iso alcohol do any damage to the heads?

 

[soul]

It is something of a observation thing. Does oxide pile up on the single track or does it spread across several? Tape that is being shaved will go on several tracks- pull some 1/2 inch sandpaper through the stationary guides to remove edges that are sharp enough to shave tape- usually the worse edges are at the outer edges. This is a maintenance issue but if you do not have it worked on by a professional then you need to do the same thing. The other issue is pole pieces sticking up shaving oxide. This is harder to fight with- I sent a head to JRF to have lapped and it did the same when it came back. Pole pieces wear slower than the surrounding material and if they stick up they will for only that track pile oxide up on only that track and cause it to decay in response and I have sen it happen. It seems like maybe NU Finish Car polish might help with the lubrication surfactant it has in it- make the tape slide across heads better. Otherwise new head is in line. It is more economical to see if stationary guides have edges or sharp spots before changing a head.
OH, The sandpaper I cut to larger than 1/2 inch so that it wraps up and takes care of the side cuts is 400 or 600 grit not 100. The TSR8 is a low cost machine and why it does not have ceramic guides on it like the higher up Otari decks have. If you have machinist ability or know someone you can have them made- ceramic is harder than glass and is only bettered by Zirconium and Diamond.

Thanks for your super informative replies as always SkywaveTDR! When you say oxide, do you mean the tape residue? the brown stuff that comes off with alcohol?

I read about the Nu Finish polish somewhere else. Does that help reduce the amount of tape residue that sticks to the heads? I think the heads were relapped right before I bought it. I've only recorded around 10 hours or so on it since. I can take a photo this week and post it here.

One thing that is likely contributing to the issue: I am using a tape that was already recorded on, I bought it used (they said it was recorded once) but most of seemed blank. I am going to buy brand new tape today and see if that makes any difference.

 

[SkywaveTDR]

I only use Denatured alcohol in my shop. The Iso is for cuts and PCB cleaning. The stuff I have is Anhydrous lab grade not the water stuff from drug store. Denatured is found in a paint store or at home depot or other big stores. Oxide is the brown stuff the same color as what is holding your sound. It is not good to see it coming off all the time. New tape due to it new edges will shed more than used tape initially. This has been true ever since I have worked with tape but most noted at Teac in 1982. This is normal.
The Nu Finish is amazing stuff and why I polish heads with it as it cuts down the tape to head contact friction and I have seen it reduce level variations from 1 dB to 1/2 dB. I think it may even make the heads last longer as any lubricant will. I would round off or reduce any wear edges on a lifter with sandpaper and make sure there are no cuts on the stationary guides- this may be where these oxide residues are coming from as each pass it is shaving oxide off your tape

 

[soul]

Hey all! Your fav noob is back with more problems...

In October, I had the machine running fine (with your help) with a slightly used reel of Ampex 456. I was able to bounce a song from Pro Tools to the TSR and back with no problem. I bought a tentelometer and checked the tension on that reel. Everything was running smoothly. The Signal was strong with lots of cleaning.

Now I'm ready to bounce an album worth of songs. I bought some reels of NOS 456 on eBay. I put the first reel on, and it's speeding up and down (and some signal loss but I think that's resolved by thorough cleaning each pass). In FF, the tension arm on the supply side isn't moving up unless I help it by pushing it up with my finger. Rewind too, but not as much.

I've decided to FF the whole tape, then rewind it back to start. Not sure this will help. FWIW: I can see a little bit of tape shredding as I do this

Q: Is it standard practice to run a new reel through, then rewind to "loosen" it up? Nothing else has changed since October when the TSR was running fine.

Always appreciate your advice here. Happy holidays everyone, Steve

 

[BRDTS]

Not sure I'd call nos tape "new", but yeah, when I historically bought new tape....and occasionally buy new ATR tape now, I would/do play (not ff) the new reel beginning to end. Granted, I'm also striping smpte. I then use spool mode to rewind.

Even before I used smpte (back in the 80-8, 25-2, 90-16 days, I'd play brand new tapes from beginning to end, then rew if no spool mode.

No science for it. I just did it. smpte gave me another reason. In theory, it's one more thing wearing on heads....but I never really worried about that.

If I drag out a 1968 multitrack to transfer, I bake it, play it all the way through to judge if it's gonna be problematical, maybe bake it again (or not) and do the transfer with fingers crossed.

My advice, at some point, buy some actual fresh new tape as a comparison.

 

[soul]

Thanks, BDRS. I will buy a new reel in the future. For now, I took advice from SkywaveTDR (above) and bought some nu finish, coated the whole tape with it as I saw posted in another thread. Then polished the heads and guides and cleaned them afterward with 90 iso alcohol.

The signal is better now. Tape speed is consistent after the first 3 minutes or so.

Track 7 is the one that loses signal still.

Does anyone know the track config on the record head? Is 7 on the outside by any chance? I don't see any oxide on the head, wondering if something with the alignment or something happening at the edge is causing 7 to lose signal?

My next move is to use the sandpaper Skywave suggested to smooth the edges of the guides.

 

[soul]

Welp, I dunno what happened. But now after a few hours, all tracks are losing signal, and playback speed is erratic. I think I've done everything but degauss. Could degaussing help with these issues?

 

[soul]

Ok, I think the tape is F'd! I put on the newer reel of Quantegy 456 which I got with the deck back in 2015. Way stronger signal! There was one drop-out after a minute or so, but I can work with that (I'm at the end of the reel, maybe some buildup). I suppose it's time to buy some new tape! I thought I found a deal with these Ampex 456 sealed tapes, bbought four of them for $50 each. Lesson (maybe) learned.

 

[-mjk-]

Years ago, I had a Tascam 8 track with 1 track that seemed like it was getting clogged up with tape oxide. It acted exactly like tape shedding but there was no visible evidence of it on the machine, anywhere (no flakes and nothing visible on the heads). Nevertheless, that 1 track was not working properly and I was unable to record a session, so I decided to get the head re-lapped. The re-lapped head did the same thing! Because I had been trying to record a new session and ran into this trouble, I had not dared to play back any previously recorded tapes, thinking that the head must have an issue since nothing else was visible wrong. After the re-lap, that same track kept acting exactly like it was clogging up and I was stumped. Finally, I cleaned the heads and put on a session tape and the session played back perfectly, no issues. After verifying that a number of times with other session tapes, I concluded that the new tape I had bought was defective. That being 1981, I couldn't look it up on the internet. It was some time later that I heard other studios were having the same issue with that particular batch of tape. So, it's possible to have a tape issue that is not verifiable by normal visual inspection.

 

[SkywaveTDR]

Even good tape can leave a shed like oxide on the heads. I have new SM911 tape here and I had some decks that would gather up oxide on certain tracks consistently. I think the pole pieces are harder that the surrounding material and when a head wear down like this then the lapping will not work as it did the same thing after the lapping. I don't know the answer in this as head wear in different ways and some of the ways might yet be discovered. The buying of sealed 456 may only be a deal if at $20 where the reel could be what you are buying when the tape turns out to be sticky. Otherwise I suspect the SM911 will be the best tape to use, Tape like ATR Master is a thick tape having a thickness in excess of 2 mils and thus then does not help with tape compliance to the head for older machines. There is nothing wrong with the tape just that it does not like to bend around a head the same as a thinner tape will do. Some go in and play with setting on machines where they do not know what they are doing. The last 48 I had in has real low back tension but both setting seemed to be wrong but the purple LEDs in the meters told me what I was dealing with.

 

[soul]

Thanks for sharing those stories. I assumed unused, sealed tape would be good to go. Another lesson learned. I'm asking for a refund on three reels I didn't open, fingers crossed.

Man, there are so many variables and pitfalls with analog recording. But I'm committed to bouncing this album from Pro Tools through the TSR8. So, I'm not giving up yet. Maybe I'll even get the hang of it along the way as it's costing a bit more time and money than I planned.

Really appreciate you guys helping me through!

 

[SkywaveTDR]

You know a lot of money could be saved and also what correct machine to use for bouncing audio would be answered if only given to the proper people to answer them. Presently I would use either SM911 or ATR Master on a 1/2 track deck to get tape sound after the audio is mixed down to two tracks. Bouncing audio to a 8 track deck with real questionable track with especially at the edge tracks is going to make a mess of the audio. Now I have no problem with a 1/2" half track but usually at 15 IPS the 1/4" tape will do. The way to get good opinions is to find your experts and stay with them- maybe more than one opinion will help.

 

[SkywaveTDR]

Welp, I dunno what happened. But now after a few hours, all tracks are losing signal, and playback speed is erratic. I think I've done everything but degauss. Could degaussing help with these issues?

Demagnetizing these tape paths will be a big waste of time and also a possible way to wreck circuits. Some people do the demag with the machine on and you are applying million of times the level that the tape produces and so many people mostly on cassette deck have blown out the head preamp IC's. Since there is nothing in a tape path to retain magnetization then there is no reason to demagnetize the tape path. On test I did at Teac when it was slow the same readings were there before and after the demagnetization process with the Handy Mag which is the best one to get and further tests done with a new roll of Maxell XL I tape with 50 passes of a recorded 10KHz signal indicated no affect to the signal even after 50 plays. So the measured residual you so on a meter doe snot affect the tape signal and 50 play is more that a tape is likely to see which is why I selected it. Yes I have two courses of Electromagnetics in Engineering school.

 

[soul]

Thanks as always for the insight and patience Skywave! While I understand that sending the machine to an expert would be the ideal path, there is something in the process of discovery that I'm interested in as much as recording itself. As long as I don't do any permanent or costly damage, I'm learning and enjoying the process. I'm grateful for all the guidance along the way.

FWIW: the whole purpose of this project is to add some tape quality, analog character to an indie rock album I'm about to release. I want to character to the album even though it may reduce the fidelity of the digital tracks. I'm bouncing 4 stereo stems from PT to the 8 track (drums, bass, vocal, instruments) then back into Pro Tools for final mastering. Would you advise just bouncing the stereo master to two of the tracks on the TSR? If so, which two tracks on the machine would you use? I don't have a two-track tape machine (other than a cassette deck) Thx!

 

[-mjk-]

If you hurry, there may still be time to grab a free Izotope plugin called Trash. I was pleasantly surprised at how realistic their tape distortion was.