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While copying a 28 year old cassette recording to the hard drive
(using an Echo Mia card and Ardour) from a Teac A-660, I've suddenly run into
a problem with fluctuation in high-frequency response; sometimes, the
high frequencies sound muted every other second or so, sometiems for
far longer periods, etc. I don't think it's the tape, since when I stop
and play parts of it again, the problems either go away momentarily or
come back---sections that sounded bad before sound better, and
vice versa. There appears to be some tape shedding, since the tape
head gets sligntly dirty, so I don't want to play these tapes any
more than I have to. I don't have a precise temperature controlled
oven to bake the tapes in to stabilize the binder.My other cassette deck, a Kenwood KX-1030, which I believe is a higher
quality deck than the Teac A-660, needs a belt replaced, so I can't
try the tape on that yet. I was planning on copying the tape to both
another cassette tape and on reel to reel tapes (from the KX-1030
to a Tascam 34B at 15 IPS) as well as onto a hard disk (then
to CDs (bletch!) and at 96KHz, 24-bits, onto an audio DVD.It's only been about a year or two since I've replaced the belts in
the A-660 (what fun that was, sarcasm intended... is the Kenwood any
easier?) so I'm not so certain that the belts are bad already. The
A-660 has always been reliable and I've never noticed fluctuations
like that before. Once, I swtiched the Dolby, EQ and bias to
different positions, the HF returned for a longer period of time,
but perhaps that was just a coincidence, since I couldn't replicate
that happening (note: the increase in HF occured when switching
from no dolby to dolby along with going from normal to CRO2, which
was the opposite of what I'd expect; I suspect this is a type I (?),
non-CR02, non-metal tape and recorded without any dolby since I
can't hear the s'es at the ends of words clearly with dolby on or
when selecting CRO2. Does this sound like a coupling capacitor
going bad? I've always found such caps to either work or fail, not
produce intermittent symptoms, but, perhaps they can fail
intermittently, or caps in the dolby, bias or eq circuitry are
failing?I haven't given a good look at the PCB, but I know that my 34B had
quite a few cold solder joints, and I think the A-660 is from the
same era, and wonder if its known to have similar manufacturing
defects requiring a soldering iron to be fired up to repair.The tape has no brand name on it; its a copy of a recording of a
live performance that recorded and duplicated (and mastered?) by a
recording company in 1979, named Ster Art, in Resisterstown, MD.
Does anyone know if Ster Art is still in business wiht another
name and possibly retains copies of master tapes from recordings
made in the somewhat distant past (1979 doesn't seem all that far
back! ...I must be getting old).Thanks for any help that anyone can provide!
--Thrifty
Follow Ups:
This sounds like the tape isn't maintaining good close contact against the head. The tape could be curling or other tape damage over time, or a deck transport issue...but maybe something isn't right with the pressure pad on the cassette itself. You know, except for a few high end machines, the transport (guides, pressure pad, etc) are in the cassette shell itself, not the deck. Its possible that the pressure pad in the cassette shell--right where the head makes contact--isn't providing good contact with the head. Sometimes the pad can get misaligned, the springiness goes away, or I've even seen the pads fall off all together. You can have a look and see if its in place, gently poke it to test springiness. If things look bad, if the shell can be gently opened, you can transplant the tape into a better shell that has screws to open/close. I've done this, its not hard and can help.
Thanks! The pressure pad was the problem; I should have noticed
that. This afternoon I popped into Walgreens and bought a pair of
cheap Maxell tapes with screws in the cases. Upon disassembling the
old and new tapes, I didn't see any noticable differences in materials, etc.used in the cases other than the following:1. Color of the shells
2. Plastic in the old shells seems stronger/sturdier
3. The new liners are clear rather than the same color as the tape
in the old shells; the liners in the old shells show a little
wear, but the tapes have only been played a few times over the
last, nearly 30, years.
4. The the large rectangular piece of metal behind the pressure pad
and spring is much thicker, and doesn't flex, in the old cases.What I did was just replace the presure pads and springs in those
two old tapes. Should I have replaced the liners a well? The old
tapes have no brand name on them; the new tapes are from Maxell
and have "energy efficient and anti-reonance cassette mechanism"
printed on the shells. Is that just marketing hype from Maxell or
is there likely to be anything better about the new shells than
the old ones? Are the new shells likely to be safer for the old
tape?Anyway, the high-freqencies are once again consistent. Thanks
again for the help!
It's an excellent idea for an old tape, that maybe was build with poor cassette shell manufracturing, whether it sounds good or not.It's easy (remember to first rewind it completely) and improves the reliability of old recordings (and maybe its sound if pressure pad is bad).
I would say that the tape is dirty, and it makes the head get dirty that eventually is cleaned by the passing tape again.I would play the tape two or three times, while cleaning the head often. So you would pull out much of the dirty it has.
Sometimes I've used a small cotton with alcohol to clean the tape while rewinding or playing to achieve the same.
Another possibility is that the pinch roller are a bit worn out and presses the tape up and down slightly, missaligning it with the heads. This would also cause a lot of wow and flutter that you probably would hear.
My experience would suggest some sort of transport problem. Any noise, high pitch, rattle etc.? Are the belts OEM or general replacement? Too tight can cause motor bearing problems. Pinch roller? What you describe appears to be caused by un-even tension on the tape as it's being pulled through. Intermittent take-up tension. Just a few ideas. Good luck
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