Tape Project Forum
General Category => Prerecorded Tapes => Topic started by: mep on December 18, 2008, 09:37:24 AM
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Every 4 track tape I have heard on at least 6 different reel to reel decks suffer from cross talk. When the music gets quiet during a cut, you can always hear the reverse side of the reel playing across the heads. Is this intrinsic to 4 track playback? Is it possible that every deck I have heard has had the playback head misaligned?
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Is it possible that every deck I have heard has had the playback head misaligned?
It sounds like it. You will have to try adjusting the alignment of the head to find out.
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There is almost always some crosstalk in my experience. It may be right down at the noise floor but you can always hear it if there is nothing going on on the program you are listening to. Print through might be louder on some tapes though. Cross talk is certainly lower than 8 track cartridges. They are horrible in this respect and it is head alignment. Cassettes seem to be immune to it to a greater extent. They are not interlaced track. Perhaps heads had improved by then. Or the levels on tape are lower.
As I understand it the concept of interlaced track was initiated in 1/4 track stereo tapes for increased L/R channel separation, so there must have been an issue with crosstalk at least within the head windings if not track to track in the early days. Perhaps they had trouble building heads with gaps that close together at first?
Later 1/4" four track became a project studio standard as well as for quadraphonic open reel. Heads had 4 gaps.
I have never paid attention to how far down the adjacent track is in those scenarios. Again, I think it is audible in the absence of program material on the track you are listening to.
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I've found that crosstalk as well as print through varies quite a bit from tape to tape. I do have a number of tapes that at normal listening levels, it's inaudible but if you really crank up the volume, there is some. In particular, London's releases seem to have the most while very early releases have almost none. Another factor that has a great deal to do with audible crosstalk is the dynamics recorded on the tape. Barclay-Crocker used to record some of their tapes with unusually high amplitude levels in one direction only (using only half the tape width) to avoid this problem. The Ozawa Rite of Spring is one example of this. Print through is an entirely different problem though and that has more to do with time and usage. I have a number of tapes that were still sealed when I got them and by the very fact that they've never been played (which means that the exact same layering of the tape layers have spent the last 30 years up against each other increases print through) makes this problem more likely and audible. The best case would be if the previous owner had taken the tape out and played it once a year or so, changing which layer was on top of a given layer of tape.
Both of these problems can be worse depending on the tape stock. I believe that's one of the reasons that London's releases have more problems with these. But the very worst are the tapes that they've crammed 2 albums onto one tape. To do this, they used tape with a thinner backing. These tapes are much more prone to the above mentioned problems as well as stretching, breaking and general tapehead madness. I avoid these like the plague that they are!
BTW Welcome to the forum.
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I'm sure it's going to vary from tape to tape. Our experience is pretty much that you could dial in a given prerecorded tape to minimize crosstalk, then throw on another and have to tweak it all over again. It's further complicated when you have both 1/4 and 1/2 track playback heads on one machine, because tweaking the 1/2 track adjustment can throw the tape alignment off on the 1/4 track head. When we align machines here we listen to a couple of different 1/4 track tapes with music on them during the actual alignment process to make sure we are hitting a position that minimizes crosstalk with a range of tapes.
This is the kind of thing that makes me dream about a dedicated playback transport with only a single playback head and a scrape flutter filter in the headblock...
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Yeah, I know what you mean Doc. Richard Hess uses some custom headblocks that John French built for him on his A80's that can move the playback heads up and down in a precise and repeatable manner. He has to deal with transferring tapes that were made on improperly aligned machines not to mention some of the whacko track alignments that were tried by various companies but were never widely adopted by any other makes.
I do find some of these problems to be a little annoying on some of my tapes, but in the long run, most of them aren't that bad. I'd say that out of the hundreds of prerecorded tapes I have, maybe 5-10% have a quiet moment or two that either the cross talk or print through break the flow enough to be distracting. But that nice rich tape mid bass to midrange is worth these little distractions IMHO.
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Another point worth mentioning is that if you run a 4 track tape over a 2 track recording or playback head, the magnetic 'conduction' of the two track heads will spill some of the information of the outer tracks of your 4 track tape into the center tracks and vice versa. This is especially true when the 2 track heads are butterfly heads. So running your 4 track tapes over a machine that has both 2 track and 4 track heads on the same head block will, to a certain extent, permanently increase the cross talk between the forward and the reverse tracks.
Not a major deal, but it is noticeable.
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Thanks for all of the responses. I just wanted to make sure that everyone was "enjoying" the same cross talk phenomena that I was with 4 track tapes and I didn't have a head alignment issue that somehow would miraculously disappear if only I had the heads aligned correctly. I tend to listen to music at "realistic" playback levels vice background music levels and the cross talk from the other side of the tape is always there making noise. Of course you hear it more when things get quiet, but I think it is still mucking up things in the songs you are listening to because it is being amplified and mixed with the music.
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I tend not hear cross talk, but I do hear tape hiss if I got the volume
up. What I find more of a problem is bent tape reels and the tape
rubbing against the rim of the reel. About 1/3 of my tapes have
bent reels.
Doc did you ever find a source for 7" low tourqe plastic reels?
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Ben, it sounds like you tend to listen to tapes at low volume levels. As for tape hiss, that is always a problem too, but I can dial that out much easier than cross talk. My Revox A-77 is a master of noisy repro electronics and it has just been gone through by the Revox guru in Tennessee to the tune of $300. It will be up for sale very soon.
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Umm I like to keep my amp under 1 watt. :)
I have a 2A3 SET and two watts is peak power for me.
I don't have any LP's so I thought I would get into tape this last year.
The digital hype CD's, DVD/A,SCAD all left me disappointed with listener fatigue.
For now I am just going after Mid - Hi-fi in my system for now.
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Doc did you ever find a source for 7" low tourqe plastic reels?
Well, I'm not Doc but I can answer your question. It seems that all the stock of 7" low torque reels has been exhausted, and the manufacturer has destroyed the tooling so there will probably never be any more.
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Umm I like to keep my amp under 1 watt. :)
I have a 2A3 SET and two watts is peak power for me.
I don't have any LP's so I thought I would get into tape this last year.
The digital hype CD's, DVD/A,SCAD all left me disappointed with listener fatigue.
For now I am just going after Mid - Hi-fi in my system for now.
Ben, I'm glad there is at least one other person who has a 2A3 SET amp. I don't have problems with playing pretty loud with my 103+db efficiency speakers. The Avantgarde have an advantage, the woofer is separately powered, so my 2A3's are only driving the midrange and treble horns. I get a whopping 3.5 watts out of my 2A3's. Mostly I am listening in th milliwatt region. As Nelson Pass says, the first watt is the most important and to my ears, the 2A3's are the sweetest. LP's are the heart of my collection. Larry
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I am sad to say I was going the digital route ... so I have no LP's to speak of.
I was hoping to upgrade my amp but I guess it will wait a while with the low canadian dollar. I most likely will building bottle head tape pre-amp after I save up for this years new TP tapes.
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I also found that the tape head itself can have something to do with it. The "original" Revox G36 quarter track heads (in the round metal can) had "objectionable" (to me) crosstalk. Haven't experienced a problem with properly aligned Nortronics or Bogen heads.
Charles
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the manufacturer has destroyed the tooling so there will probably never be any more.
That's what we say about Paul, too - "they broke the mold..."
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The quarter track format offers cross talk, usually in the lower frequecies.
Ampex heads fare better than some others.
If the frequecies in the background are above 200Hz, you may have an alignment issue.