Good cassette player?

My less expensive Nakamichi decks (250/350/550/600) did not always sound right with tapes recorded on other decks (Aiwa, Akai to name a few).

The exception was my 700ZXE, but it retailed for around $2.5K in the early 80's.

This is why I suggested trying the deck that they were recorded on, though a T/F service would probably make more sense (unless the OP is going to get back into cassette tape on a regular basis).

DeKay

Try to find the same model deck you recorded them on (in good operating condition) and use single ended IC's as already mentioned.

Otherwise just send them to a transfer service (T/F to CD and/or a memory stick).

DeKay