I doubt the problem you hear is azimuth drifting off even though it does
tend to drift off a little from start to end of a cassette side. Mind you,
if you have summed the stereo tracks to mono, azimuth gets a lot more
fussy.

Auto reverse decks were usually a compromise, trading off reliability for
convenience. The rotating head mechanism was a weak point, alignment was
more unreliable, and the auto reverse and repeat feature meant the head,
and the whole deck, could get very heavy wear.

Regardless of whether it's a reversing type head or not, worn heads tend
to collect dirt and tape gunk in the edge crevices caused by tape wear, so
there be more problems losing treble as the tape progresses. The wear can
also mean it is hard or impossible to adjust azimuth without the tape being
forced out of the wear groove and the signal drops. It can especially be a
problem on the Left track which is right next to the worn edge.

Many Nak machines, and the Tascam 122 Mk II and III machines, have less
problems with dirt fouling the head because the head receives less wear in
the first place, and the wear pattern is smooth and even. The pressure pad
no longer creates nasty wear patterns on the critical part of the read head.
Some later Nak models have heads with relief slots cut into them from the
factory which makes them even less susceptible to dirt buildup in crevices
and loss of signal.

Really for serious ingest, tape heads need to be in tip top UNWORN
condition, or problems are more likely. As it used to be said, the tape
head and its condition is the heart of the tape machine.

Tim Gillett

Perth,
Western Australia


----- Original Message -----
From: "CJB" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, October 10, 2018 2:47 AM
Subject: [ARSCLIST] Problems Digitising Cassettes.


> Problems Digitising Cassettes.
>
> I guess this is a project known by thousands maybe millions. However I
> am running up against problems. Remounting a spool of tap into another
> shell is easy enough. So too is reattaching lead in / out tape - 3M
> sticky tape is ideal, using a sharp pair of scissors to trim any
> overlap.
>
> But the real problem is the actual playing of the cassette tapes.
>
> I use iMic and Behringer devices for the actual digitisation,
> capturing with Audacity. I then do a Save As... in WAV, FLAC and MP3
> (320 kbps) formats.
>
> I have a variety of double cassette decks - all relatively brand new.
> They have auto-reverse and switch from the first cassette tape to the
> second automatically.
>
> I always clean the heads manually first, then run a head cleaning
> cassette, before mounting the cassettes. The cassettes are then
> rewound forwards and backwards to even up the tape layers.
>
> I have to assume that the read head azimuth settings are OK. I have no
> way to adjust them.
>
> So far so good.
>
> BUT the digisations are far from perfect.
>
> The first side of cassette one is nice and clear but the sound gets a
> little 'muddy' (loss of clarity and treble) towards the end of that
> side. The cassette then reverses direction and the 'muddiness' becomes
> more pronounced.
>
> This effect is repeated when its the turn of the second cassette.
>
> Sometimes when I'm busy after the second cassette has run its course,
> the first cassette starts up again. This time the recording has lost
> all treble, and the digitised recording s all but unlistenable.
>
> This is driving me mad, and has wasted so much time. But it indicates
> a serious sticky-shed issue, likely exacerbated by the cassette
> pressure pad forcing contact onto the read head.
>
> Now I have bought a second hand Nakamichi DR 10. This has one
> difference to the above decks. It has a cassette pressure pad lift-up
> device, so that the tape passes across the read head passes across
> with very little pressure. Hopefully this will keep the sticky-shed to
> a minimum.
>
> What I do find strange is that others maybe with even simpler tape
> players manage to digitise their cassettes with no reported quality
> issues.
>
> CJB


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