I know they are not walkman's, I know they are not very valuable, but I always had a fascination for portable voice cassette recorders. I recently got two Sony's, one old TCM-6DX and one more "recent" TCM-S68V. They both work and that is nice, but while fixing them I noticed that the head azimuth is way off from correct position. They are mono machine, but correct azimuth ensure tape exchangeability otherwise each recorder will play decently only self-recorded cassettes. It is not that the azimuth changed over time, I have the last tape recorded with both and they play fine only with the original azimuth, if I set the azimuth correctly, the tapes play muffled. To me it looks like azimuth has not been adjusted in the factory at all, they visually just set the head more or less aligned and that is all. I was not expecting that from Sony ....
they never thought you were changing cassettes from unit to unit and for plain speech (dictaphone-function) sound doesn‘t matter as long as you can understand the recorded words... sony wasn‘t better there than all the other ones, funny i made same experianca with all my tiny (voice-corder) reel-to-reels, except the nagra sn‘s (...as they were made more at broadcast-standard).
Actually it was not uncommon back then to use such recorder to record a university lesson for a friend and then give her/him just the recorded tape. If the two recorders have different azimuth, it is hard to understand what the teacher said: when recording voice from a distance, high frequencies are quite important to understand. Once the azimuth is corrected, music does not sound so bad, not worse than music played through a modern cellphone Also they both have a decently sized flywheel that provide good W&F, better than some of my walkman's with full plastic flywheels. Frequency response is also better than specified.
i know what you mean, many of those units have a better quality than their „stereo-derivates“, as they are pro- or at least semi-pro units (...and i‘m the last one you‘ll have to explain that) ;-)
I wonder if the wider head on a Mono recorder make tracking errors more pronounced. If the head is twice the width as two tracks on a stereo head then presumably a skew on the head would cause twice the difference between the two edges of the track. One of the effects o playing a mono recording with a skewed stereo head would be to cause a delay between the left and right channels. With mono device the same delay would just cause cancellation of the sound before it even reaches the amplifier.
I guess it was just a way to save on manufacturing costs: the TCM-S68V has a specified frequency response up to 6.2 kHz, but to properly align the head I used a 10 kHz tone which, with the correct azimuth, is clearly audible (I basically set it by ear...). So both the head and the amplifier are capable of a wider frequency response, but Sony is under-specifying the unit so that it passes without azimuth adjustment. As said above 99% of users of such devices would use them to record and playback their own tapes, so azimuth is not a big concern in a similar scenario. What I noticed adjusting the azimuth is that with a wider mono head the sweet spot is much narrower, half turn of the screw and high frequencies are gone. Stereo head are more forgiving (again by ear) because the tracks are much thinner.
