Got this little reproducer from one of the HRSA auctions . It is in great working order . I thought its worth a thorough going over. Photos sent today .
I think they did not come up with the name "Speaker" for some time after this. I just find the workings so amazing.

Photos uploaded.

One will tend to find that the Horn type were "sound reproducers" and referred to as speakers, with the introduction of the driven cone, with great fanfare by the likes of Stromberg -Carlson, who in 1926 promoted the fact that a companion to their No 601 receiver was a new "Cone Speaker". That would have been possibly based on the Western Electric one.

I serviced an "All American Mohawk" of 1928. Most interesting set (have photo's) speaker assy 10Kg Chassis around 20+Kg (did weigh it) AC filaments with genuine "Humdingers" on the filaments. Fascinating phase fault on them caused by corrosive rivets. Eight tubes.

Speaker is one of the first "Rice-Kellogg" modern moving coil one's with a field coil, rather than the "Rocking Armature" as Carl has. It has been re-coned with a Foam mount. Fantastic sound multi stage TRF. OP is a now extremely expensive #50. Grid bias for it was a #24 wired as a rectifier (-84V 450V plate) 4.6 Watt OP.

I would greatly like to get some kind of period correct speaker for my 1922 ericcson 4 valve one day. Not much choice up here in Qld as far as I can see. That one looks great Carl

The Peerless looks to be in excellent condition, far better than the "reproducer" of a different make I have.

Same sort of driver, rocking arm ? but mine is in a rather shabby condition. The driver coil and matching transformer measure out ok with a ohmeter however would need a full stripdown and clean.

Only get a faint sound when hooked up to a 3 valve regen set I made even with strong signals.

Will be quite an exercise to pull the driver to pieces and clean it up. Have been rather hesitant to do anything as a pretty complex device and concerned I might damage something.

The balanced armature speaker is somewhat the same as a rocking armature microphone used in Phones. I have a Peter Lankshear article (for one) and their operation is rather simple with few actual moving parts.

As I see it the stiffness of the cone can be an issue and the pivot of the armature another. I have no doubt that the strength of the magnet is another. Some like Carls may use a flexible coupling rod of rubber, that can harden.

I would be tempted to insulation test primary to secondary on the transformer, as I have seen that old lacquer coating fail.

Fascinating device. Now there is a challenge , make one as a project.
I might give it a go.
Fred.

That could be made as an electrodynamic, but with the strength & higher flux density of some of the Magnets of today there is the possibility that it would be a lot more sensitive.

Marc

Well I got the time to finish this baby last weekend and I have sent the photos to Brad. Its good for another 80 odd years now.
There are a few threads hanging out the seam at the back. Nothing a razor blade wont remove.

Photos uploaded to Post 9.