Smokey wrote:
Does anyone have a small PM speaker...no more than 1.59-inches in diameter
and 3/8-inch deep that would fit inside a vintage Brush headphone? Ideally I
would like to find a high impedance (30K ohms on up) earphone cartridge but
can probably make a small speaker work for the purpose I need it.

Go to the dollar store and get a pair of disposable Walkman headphones.

If you want high-Z, have you considered using a crystal microphone in reverse?
Digi-Key should have some cheap crystal mike elements. They won't sound as
good as a disposable Walkman headphone, though. But they won't sound any
worse than the originals.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."