On Oct 6, 8:22*am, frank wrote:
Hello all,

I've been given an old Hammarlund SPR-210. It needs a good amount of
restoration but appears complete inside and outside. I've seen on the
manual that it has 600 ohm speaker output and I was wondering where to
find such a spekear with this impedance. Probably there's need for an
external audio transformer to use any low impedance (I have many
in the 16-4 ohm range) speaker?
Any hint is welcome.
Best regards

Frank IZ8DWF

The usual fix is to use a 10-watt, 70-volt line to voice coil
transformer. The 10-watt tap on a 70-volt line to voice coil
transformer will provide a decent match to a 500/600 ohm output. In a
pinch, an ordinary filament transformer will do. Get a transformer
with a 120-volt primary and 12.6-volt secondary and connect the 120-
volt winding to the receiver and the 12.6-volt winding to the speaker
and you are done! --Ed