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nomisimon · 23rd Oct 2021, 10:30 pm

Hi everyone

I recently acquired a quite nice Celestion PPM Soundex speaker from around 1932 I think. It still sounds remarkably good. There is a tapped transformer inside which connects to three terminals to provide low, medium and high impedances for the output stages of receivers of the day. I've measured the DC resistances but really need to know what expected 'impedances' were that the tappings provide. I've found adverts that describe the speaker unit and that it has the three choices, but none tell me the actual values.

I wonder if anyone can help, it would be much appreciated?

I've attached some images of the speaker model I have.

Thanks

Simon from Northumberland

23rd Oct 2021, 10:30 pm	#1
nomisimon Triode Join Date: May 2016 Location: Corbridge, Northumberland, UK. Posts: 18	Celestion PPM Soundex Speaker Impedances Hi everyone I recently acquired a quite nice Celestion PPM Soundex speaker from around 1932 I think. It still sounds remarkably good. There is a tapped transformer inside which connects to three terminals to provide low, medium and high impedances for the output stages of receivers of the day. I've measured the DC resistances but really need to know what expected 'impedances' were that the tappings provide. I've found adverts that describe the speaker unit and that it has the three choices, but none tell me the actual values. I wonder if anyone can help, it would be much appreciated? I've attached some images of the speaker model I have. Thanks Simon from Northumberland Attached Thumbnails