Hi, my deck has a Right and Left bias setting and a Right and Left level setting during recording. I calibrate these for each tape I use on recording.
However if I calibrate these settings at the beginning of a tape, they are not calibrated ad the middle of the tape and they need recalibration. This does not happen in all tapes. Some tapes only need minor calibration in the beginning and in the middle, but some others need recalibration in the middle.
Have you come across this issue before? Is it a tape problem (old metals)?
Is there any way to correct this other than recalibrating before each track recorded?
A second question from this one, is that the bias and level Right and Left channel knobs need to be set at much different levels for each channel, so that the bias is calibrated acording to the deck calibration procedure. Is it a fault that the L and R channels bias and levels are much different in the respective knobs?
However if I calibrate these settings at the beginning of a tape, they are not calibrated ad the middle of the tape and they need recalibration. This does not happen in all tapes. Some tapes only need minor calibration in the beginning and in the middle, but some others need recalibration in the middle.
Have you come across this issue before? Is it a tape problem (old metals)?
Is there any way to correct this other than recalibrating before each track recorded?
A second question from this one, is that the bias and level Right and Left channel knobs need to be set at much different levels for each channel, so that the bias is calibrated acording to the deck calibration procedure. Is it a fault that the L and R channels bias and levels are much different in the respective knobs?
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Bias requirements can vary along the length of the tape due to variance in the tape formulation.
I would expect the channels to be very close to each other in a properly functioning recorder.
I suspect it is not the recorder problem because in some tapes the bias settings are close whereas in some others the level settings are close. But there are some tapes which require quite different left and right settings.
Saying so, all of the tapes are 90s, played in inferior quality (but not dead cheap) deck.
Yes, I have come into this conclusion myself as well, based on what discussed in this forum.
However, I struggle to understand what has been done wrong in my cassettes storage from 90s to date.
I mean, this happens also at some metal cassettes (eg. maxell metal capsule 90), that show no visual signs of tape wear. These have been placed vertically in a container and in their own plastic holders. There is no dust inside these holders and there was no direct sunlight onto them. I cannot say about humidity and temperature differences though.
And these tapes have the same wax stink as they had when bought new on 90s.
It could have been stored better but I do not think this was such a bad storage. Are tapes so sensitive?
Yes, they are. Remember that radio stations store their audio heritage in air conditioned rooms of constant temperature and humidity just to avoid early degeneration.
Best regards!
Best regards!
If you are continuously recording on a tape, from the beginning, the bias oscillator circuit may heat-up to a point where it may change the amplitude....
Easily confirmed with a tone generator, an oscilloscope with 2-channels input and a can of freeze spray (I assume it's a 3 head tape-deck??)
I'd check the heads for build-up of material - a sub-microscopic scratch can wreak havoc and magnetic crud building up on the head will change the performance. Worn heads could also be a culprit, and its worth checking the tape tensioning mechanism is in good nick, as that is responsible for the tape making intimate contact with the head. Pinch roller pulls, source pulley drag provides tension (which varies with spool occupancy), and the sprung pressure pad inside the casette helps keep tape consistently flat across the head and damp any vibrations. Old pinch rollers harden up and even crack with age - must replace if so.
On a cassette all of this mechanical set-up is hard to check and investigate, a test tape is worth considering (if available any more?), as is making a test-tone recording on a different deck to cross-check.
On a cassette all of this mechanical set-up is hard to check and investigate, a test tape is worth considering (if available any more?), as is making a test-tone recording on a different deck to cross-check.
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