Tape Project Forum
Tape Project Albums => Tape Project Albums - general => Topic started by: Spirit84 on August 23, 2008, 03:37:48 PM
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I am a subscriber to the Tape Project, and I must admit that I am not a technical expert when it comes to R2R. I have received 5 TP tapes but have not been able to use my newly restored Studer A810 because on an ongoing problem with other parts of my system. You can only imagine how frustrating this is! Having the tapes staring me in the face, but not being able to play them.
Anyways - a friend of mine who owns a high-end audio store, asked me to bring over the Studer to his shop to listen, so I did this today.
We set the the EQ to CCIR and played the Robert Cray tape. There were 3 of us listening and I have to admit that we were all surprised because the tapes sounded quite awful which really surprised and upset me. We switched the EQ to NAB and it actually sounded better, but certainly not great.
Comments from the 3 of us were words like: Phase problem, lifeless, dull, etc...
What am I doing wrong. I expected to be blown away but now I am very down and depressed.
Am I missing something here? My Studer is in superb condition having been completely refurbished by a Studer expert tech.
BTW for the record - we rewound the tape onto the tak-up reel (the empty one) and then played the tape back onto the TP reel. I assume that is correct.
I really would appreciate some help - PLEASE
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Hi Sam,.. that certainly is strange since the R. Cray tape is really outstanding. Well, since you said that a tech had refurbished the unit, there are 4 possible problems.
1. The tech did something wrong
2. It was damaged or knocked out of adjustment since the reconditioning
3. There's something that you're doing wrong with either hook up or operation
4. There's something wrong with the particular tape you tried playing
To address the first 2, was the refurbishment performed for you or the previous owner? Is the tech close by or did it have to be shipped? I understand that these machines don't travel very well and often need some re-adjustment after shipping.
As far as #3 goes,.. do you have an operations manual? Revox/Studer usually has excellent owners manuals. You might try looking for similar problems on this forum;
http://translate.google.com/translate?hl=en&u=http://www.studerundrevox.de/sitemap_en.htm Take a look at the pictures and be sure you're threading the tape correctly.
Regarding #4, did you try any other tapes? Is the tape on the reel you tried wound with the dark gray side out and the shinny brown side in? If not, it got twisted backwards somehow.
You might also try and contact one of the members here, heideana. He has an 810 that had some problems from shipping so he may be able to keep it from having to go into the shop.
As far as demos go, always do a dry run at home or a friends house. Even if you have to hook it up to a boombox, have your act pretty polished before you take it out for a night on the town. If anything can go wrong, it will during a demo. If you have anything you can hook it up to with headphones (or does it have a headphone jack?), use that to test things and don't use a $200 tape when your fooling with your deck.
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it might help you locate nearby assistance.
Gary
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Just shooting from the hip. From the words used to describe the problem, sounds like a playback head misalignment problem.
I would try a record / play cycle with known good material on a new good blank tape and see if it can make a tape that sounds pretty much exactly like it's input source. If so, perhaps the tech didn't align it to a "real world" standard but it is only aligned to itself. I would try another 2 track stereo tape like an older pre-recorded one if you or your friends have one. Although not to the standards of the TP tapes, it should exhibit proper channel balance and not sound dull or like there is a phase issue. Mono parts should be clean and centered in the image. You could consider playing part of your TP tape on another 2 track stereo machine. If it only has NAB EQ it will not sound quite like the right frequency balance but still not dull or phasey.
It is hard to tell subjectively whether the problem was subtle - on the order of a different phono cartridge, or gross - as in no highs at all and/or channels wandering in and out. Improper threading might cause improper tape to head contact, or as was suggested, the machine might have been jarred from proper alignment when in transit. Did you get the Tape Project alignment tape? Could a local tech help you use that to check the alignment?
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I had a similar problem when I received my RS1500 back from Doc. Sounded terrible, through a BH-built Tape Seduction, yet. I was also disappointed that the top panel of the machine was bably bent in transit. (Thank you UPS). Since there was no apparent damage to the shipping box I can only guess, based on the pattern of bends and dents on the top panel, that the box was dropped and landed flat on one side with the top of the machine pointing down. Two of the styrofoam packing panels were broken. Doc had me play a 2 track tape and switch between 2 and 4 track heads. The 2 track position sounded much better, although not good, than the 4 track position, which seemed to have a frequency response range from about 100 hz to 1000 hz. Doc diagnosed the problem as mis-aligned heads and had me ship the machine back. It's probably somewhere around Nebraska right now.
Given the near certainty that this will happen again, I'm wondering if it is possible to ship the head block separately once the heads are re-aligned. The head block can be packed much more securely and shipped cheaply by air. Doc - what do you think?
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I want to clarify that it is strictly my SWAG is that Jim's machine was knocked out of alignment in shipping after we went through checking several other possibilities in our correspondence. It's not here yet, so I can't say what the problem is with any certainty.
The alignment procedure is all about the relationship of the heads to the rest of the components in the tape path. Once it has been removed there is no guarantee that it will sit in exactly the same position when reinstalled.
We have seen several times now when someone is having problems with their machine the machine was threaded improperly or the tape has been run with the black back coating facing the heads rather than the oxide side. It's always worth checking to see if either of these things have happened and whether the heads are clean or dirty before assuming there is something wrong with tape or tape recorder.
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I had the same type of issue on my Studer A-80RC MKII. John at JRF sent me a four track head set that on four track tapes was a mind blower. Yes the tp sounded good, but on some it was just not all there. I was dumbfounded as well. About two weeks ago Evan Mater from Vork audio came over and aligned my deck with his proffesional alignment tape. I cannot begin to tell you how big a difference it made. Like oh my god kind of difference. At one point before Evan saved me (no kidding) I called and talked to Dan about what could be wrong... I don't know what I am doing I admit. I am a Vinyl guy.... and this is my "New Vinyl" if you know what I mean. One thing Evan did find out was that the Phase of the TP alignment tape was far different than the phase of his alignment tape. I called Bottlehead, and was reffered to SF where I called and had not heard back from. Has anyone else found the alignment tapes to be correct or incorrect in phase? Again, I am a rookie, so don't shoot me if I am incorrect in how I am explaining what has transpired.
"you don't know what your missing until you have heard it" cannot be more true.
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I want to clarify that it is strictly my SWAG is that Jim's machine was knocked out of alignment in shipping after we went through checking several other possibilities in our correspondence. It's not here yet, so I can't say what the problem is with any certainty.
Sorry to have misquoted you , Doc. You did say it was your suspicion and not your diagnosis that head misalignment might be the problem. I wouldn't be surprised if it is other things as well. For that much damage to have happened to the top panel it seems quite possible that any number of things could have been knocked out of whack. Your determination to get everything right is greatly appreciated. Now I can focus on losing sleep over things that really matter.
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Please excuse the tanget, but soundlabspeakers aka ? brings up a good point.
While many of you folks are dyed in the wool ( Marie where are you?) rtrers, there are a few of us that have more money/credit than brains and the learning curve can be a bit daunting.
Just as we have consolidated the TP tape comments in one easy to find and follow thread, is there merit in a novice section with fundamental information and or links to other sources of information which would help us new comers avoid the obvious pitfalls and have some basic training material.
I know there are several threads in the Forum which already have addressed some basic issues, but once again they are spread out in different topics all over the place.
I recently bought a book from Ebay published in the 60's on how to make a better recording just to get some of the lingo down, and figure out how to add leader, store tails out and stuff like that which are otherwise Greek to me. Some of book's contents hit the bullseye, others are interesting factoids.
When some of the threads start to rattle off nomenclature like it was common English, I begin to hyperventilate.
This stuff is not intuitive; at least not to me.
Much of the exchange of information has been graciously picked up by Steve K, but he has to work and sleep sometime; don't you Steve?
The TP 'suits' also jump in, but they too have commerce to conduct.
Remember when you rtr veterans first got the bug, these machines and the information was current. Now it is for the most part niche legacy material and not as readily available as going to the dealer you bought your machine from and getting the lowdown.
I am done whining.
Please continue.
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Fantastic points CV. In the early stages of this forum, I think that most of us had some experience with reel to reel. But as the ranks of subscribers increased (and will continue to do so hopefully) the more complete novices to open reel tape will populate this forum. I realized that a good guide for the complete novice was need including a glossary and what has changed since most online info was written. The sticky at the top of this forum was as far as I got (and promptly forgot about it). That was supposed to supplement a pretty detailed guide to help choose a machine and how to use it.
Just like any technical subject, it's hard to remember all the little things that you pick up along the way that makes using these machines a pleasure to use instead of a chore. So that's where you guys could help out. CV, if you could start a new thread here in the General forum and give the info about that book that you found and title it something like Beginners Guide Suggestion Box, anyone with questions about operation and care of tapes and tape machines can ask questions there, other members can answer them and after a while, we can compile them into a sticky or a forum. When new posts start slowing down, I'll be sure to post some whacky tape story or something before it moves too far down the page.
How's that sound?
BTW Soundlabspeakers, was it a Studer 1/4 track head that John sent you or something else?
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I am on it my captain, but perhaps not tonight; but soon as I can.
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I sent him my 2 track 1/4 inch to have the heads relapped, but he sent me a 4 track 1/4 so that I could play those tapes as well. BTW a superb guy and a superb operation up there.
Soundlabspeakers is... Harry Hasbun
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One thing Evan did find out was that the Phase of the TP alignment tape was far different than the phase of his alignment tape. I called Bottlehead, and was reffered to SF where I called and had not heard back from. Has anyone else found the alignment tapes to be correct or incorrect in phase?
Assuming that you mean the phase relationship between left and right channels, especially at high frequencies. This is related to azimuth; in fact the azimuth adjustment procedure usually refers to this phase relationship, as displayed on a scope.
Azimuth is supposed to be standardized on test tapes...that's part of what we pay for in a standard test tape. I have many different test tapes, from Magnetic Reference Laboratory, Standard Tape Laboratory, and even some old ones from the Ampex test tape lab. None of them agree 100% in azimuth. They agree within a relatively small range, but not 100%. We have chosen one of our most recent MRL tapes as the standard we are maintaining. We make our test tone reels to duplicate that azimuth, and I have checked that process enough to have high confidence that we are keeping very close indeed to that standard.
One other factor can throw those readings off however. If the tape is tending to skew, it shows up with a different azimuth. Many decks show more skew when there are small reels on them, or when one reel has much less tape than the other reel. (This is actually the biggest advantage of a constant-tension transport design. Keeping the skew minimized is probably more significant than the end-to-end speed consistency, relative to a design that doesn't have constant tension.) Although most test tapes are supplied on small reels (even though they use low-torque hubs) around the studio we routinely spool them off onto 10-1/2" reels with blank tape before and after the test tones, so that the tones are in the middle of the pack. That's just to be on the safe side, since all the machines we use are constant-tension designs.
Your tech's experience comparing the tone reel to his test tape reminds me of the old saying, "The man with one watch knows what time it is, The man with two watches is never sure."
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I am sure your right, being a rookie has some very big disadvantages. I know there was a lot of work, testing and retesting. The difference was absolutely amazing. I will be the guy with no watches as long as it can tell time like it is now!
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Welcome to the wonderful world of analog tape!
In all of these conversations, it would be most helpful to have some information about the test tapes being used. There are a least two distinct flavors of CCIR EQ that have been used over the years, so I would expect to see some variations depending on the calibration tapes. In this realm, I have generally found the MRL and AGFA/BASF tapes to be the most consistent, even if they don't match exactly in either azimuth or frequency response. I am making the assumption that a good quality external voltmeter is being used for the reproduce alignment as well. Do not trust the meters on the machine to have flat response! (Although some are fairly decent)
I have compared various test tapes from MRL, BASF, STL, Norton and Ampex from over the years, and have seen significant variations between all of them. Also, as Paul points out, many decks (even those with constant tension), will exhibit significant variations in the actual dynamic "skew" of the tape as it passes across the heads. I remember tearing my hair out over this issue early in my career when working with Ampex 351 and 440 decks (as well as the Scully 280's). You could align the reproduce perfectly on a machine with one tape formulation, but the minute you changed to a different stock, the dynamic skew (and hence the HF response) would change. It doesn't matter if the tape is the same thickness-it has to do with factors related to the oxide and back-coating friction, the actual tape width (with Ampex tapes being slit slightly narrower than 3M, AGFA/BASF, Maxell and others), as well as the base formulation. On many decks (even those with constant tension), you can actually measure the difference in where the tape rides through the head stack and pinch roller. In decks without constant tension control, you could see very significant differences. All of these factors will have a profound effect on the HF response and inter-channel phase relationship of the reproducer.
It is because of these factors that at one point our studio spent a huge sum of money to have Jay McKnight of MRL make a run of tapes on something like 4-5 different stocks, so that we could use the same oxide for the repro alignment that was being used as raw stock for recording.
Although most Studer machines and the Ampex ATR's (as well as the 3M series 79 and Technics RS-1500 series) generally have fewer problems in this regard, I have still encountered issues relating to the difference in dynamic skewing on all of these machines (I use a modified RS-1520 in my home system, mainly because I don't have room in the rack for a larger deck. I still have to tweak the PB azimuth for different oxide formulations, though).
A major factor to keep in mind here is that different tape formulations will establish different head wear patterns as well, so once you run in a headblock with one oxide, and then change it, you will frequently encounter issues with spacing loss across the heads due to the fact that the tape is not contacting the head curvature in the same manner. To make matters worse, if the head tilt or rotation was wrong when the heads were first aligned, you now have an asymmetrical wear pattern to contend with. (We used to encounter this a lot when switching between Ampex formulations and others, due to the slightly stiffer base formulation used by Ampex in the seventies and eighties). If you have a different base material (acetate or polyester), the issue is even more profound.
In addition, I have seen variations in the handling of the tape on machines where the pinch roller formulation has been changed, which is often overlooked as a factor. (Even the Otari MTR-90 machines will exhibit differences in tracking with different rollers).
So, what is novice R-T-R fan supposed to do in the face of all this? The best suggestion I can make is to find somebody in your area that has experience in R-T-R machine alignment. The second would me to make an investment in a MRL IEC curve calibration tape (catalog #21J203 is the one you need). If you are spending $2500+ for a music library, spending $70.00 for a calibration tape well worth it.
For those who are somewhat technically inclined, a good quality (preferably analog) VTVM is also a good investment. You can pick up a working Hewlett-Packard voltmeter on eBay for under $100. The calibration on it will run you maybe $100 to $175. Still a good investment. A basic 'scope is also a must for head alignment. Again, a decent Tektronix or B&K 'scope can be had for anywhere from $150 to $400, depending on condition (I just picked up a good quality 4 channel Tek scope for $175). If you want something that looks cool as well, and have the $$ to spend, you could opt a McIntosh MI-2 or MI-3 Maximum Performance Indicator instead. It will allow you to make the proper phase alignment, and is fun to watch in the dark!
However, if all this is just Greek to you, start checking around your area for a good tech. Expect to pay him (or her) anywhere from $75.00 to $120.00 per hour for their time, depending on their level of expertise, and the equipment they have available.
Perhaps a section could be devoted to what resources are available in various areas of the country in this regard. Also, remember that not all techs will have the experience (and tooling) to work on all machines.
Apologies for the long post...
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Great post Scott! The info regarding different head wear patterns was new to me but it makes perfect sense. I've always advised others that even after we feel pretty confident about doing our own adjustments (with the proper equipment), that it's a good idea to take it to an experienced tech every once and a while. Considering how difficult it is to obtain parts for many of these machines, a good tech could find impending problems in other areas of the machine.
I'm not sure what test tape that the OP's tech had, but the ones that the Tape Project supplies are made on the same tape stock, and the same ATR100's that the music tapes are made on.
The bottom forum here is devoted to Service resources. I would've hoped that there would have been much more posting there by now. Of course you don't see a lot of facilities boasting about their experience working on open reel. If you have any first hand experience with techs in the areas that you've lived and/or worked, I'm sure that other members would be very grateful.
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Hi Steve,
I think the head wear pattern problems caused by different stock formulations is one that hasn't received the attention it deserves. I have to admit it took me a while to figure it out as well. It really became apparent, though, when working with magnetic film, which has a base thickness that varies between 3 and 5.5 mils thick, and a very different head wrap depending on the base thickness and base type (with the triacetate base being stiffer than polyester).
John French and I spent quite a bit of time trying to sort this out around 10 years ago, and the only solution we could come up with was to have two sets of headblocks, one for 5 mil acetate base film, and a second for 3 mil polyester. It cost a 'friggin fortune! (And then there was 5 mil polyester as well, just to complicate matters further).
As good as 35mm full coat magnetic film could be, I have to admit that I'm more than happy to not have to deal with it much any longer (except for archival work). On the other hand, I recall hearing some 6 track score masters for various pictures over the years that would just blow away most multi-track tapes. Part of this had to to with the thickness of the oxide, and part of was due to the track width, which is wider than that of a 24 track tape. I know more than a couple of scoring mixers who really lamented the move away from film. (Of course, many of the recordings that Bob Fine and Bob Eberenz did for the Mercury and Everest labels were recorded in 3 track 35mm, which, with an equivalent track width of 200 mils, could (at least theoretically) produce a recording that would only be equaled by at least 1/2" 2 track tape).
--Scott
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Interesting stuff Scott. Thanks, I always wondered about 35mm recordings (I have lots of Mercuries on record and tape). They sure can sound great. Setting azimuth and getting a good tape wrap must be a nightmare though.