Hello Jordan,
Thanks for the reply. I know this part of the question
isn't linux specific, but presumably the AD converters in something like that
aren't "as good" as those in a more expensive device though?
The Behringer UCA202 has a decent quality TI Burr-Brown DA converter
inside, nothing wrong with that. The cassette player and cassette itself
are probably more important. Most cassette players have a frequency
range up to like 12kHz or even less, not sure about the frequency rates
of cassettes themselves. But you're referring to metal cassettes which
have the highest maximum frequency rate. These rates are nothing the
UCA202 can't deal with as they're way within the rates the device can
capture.
Best,
Jeremy