Reel to Reel tape question

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Contact Jim

It definitely sounds like a head problem (worn, misaligned).  That's where I would start.  Nothing in the electronics should affect the sound with a change of direction.

1. Do you find this deficiency on both channels when you play the second side? The outer tracks, which is there the left channel lives, are more likely to show a loss of fidelity since they are at the edge of the tape and will be most prone to less than perfect alignment.

2. Good tape to head contact is essential. Even if azimuth and zenith alignments are correct, there may be a slight deviation from a perfectly vertical front-to back head angle. You might try this experiment: While the tape is playing, using a Q-tip, press the tape gently to the play head and see if the sound improves.
What is puzzling me is why you find that this loss of quality only appears on the reverse tracks.
What the head sees on your tape should be exactly the same from the forward and revers tracks, any alignment would be mirror-image, either both bad or both good. Same with height.

See if that Q-tip diagnostic tell you anything.

You know, I never thought about whether it is both channels that are affected equally. Good question. I will check on that tomorrow. My guess is yes - but only because I do not notice any skewing of the soundstage - I don't need to re-center the soundstage when I flip over the tape. But that may simply be volume, not clarity. Again, thanks, I'll check. 

And all of these are commercial,  pre-recorded tapes, usually from the 60's and 70's. Their age made me wonder if storage for 50-plus years has a greater negative effect on the first side, rather than the flip side. Doesn't sound logical, but just reaching. 

And I might call ReelAudio and talk to Jim, as you suggest, @jnovak.  He also sells calibration tapes, and would know exactly which ones my local bench folks would need.

Thanks again, everybody...

David

I did a lot of professional reel to reel and cassette tape duplication back in the day. Duplication facilities recorded all tracks at once in one pass. That means one side was playing and recording forward and the other backward simultaneously. Most duplication machines used heads with all four tracks in the same head. It was critical that we kept the duplicating equipment carefully aligned with professional alignment tapes like the ones from MRL (surprised they are still around) to prevent the very same problem you are describing. If you are having the same issue with tapes from various vendors and different time periods, I’m pretty sure your problem is head alignment which is easy to adjust with proper alignment tapes.