Replace magnet with a mono play head?

[Mike Watterson]

Thats odd because I don't think I have seen ANY cassette recorders with a magnet erase head. Maybe I have misinterpreted what type of erase head they all have.
Mike

They often are head shaped. Clue is the lack of a pair of wires.
Other clues is that they only engage the tape when record is selected. If only the play/record head moves forward on play, it's a magnet, even if it looks like a head.

DC erase seems to be rare. Easily spotted with the aid of the cheapest scopes.

Quite a lot of portable reel to reel and cassette from 1959 did have AC bias but magnetic erase, either via a magnet in a holder the full tape width (guides needed) or a head styled holder that either rotated or moved forward.

I'd love to have the vintage German portable reel to reel with battery valves and spring driven transport, also the early Sony transistor portable reel to reel that also used a wind up spring drive for the tape transport. I've no idea how bias and erase worked on them.

I don't remember any DC bias cassette players, but I did have at least one portable reel to reel that probably had DC bias. My first machine was a 2nd hand Grundig Cub for Christmas from my grandparents. Maybe 1965.