[k0nxm]

Hi all, 
    Time again to consult the 'gargantubrain'... I have a nice 51-530 'Transitone' that was a gift to my dad when he left home for college. I've got it all ready, except it's missing the speaker. I have a good speaker that's a physical match, and I can mount it easily, but it's 16 ohms and there is a little clipping going on at moderate volume levels. What is the impedance of the factory speaker? Rider's has all the other info needed, just not that. Thanks,

[MrFixr55]

Hi k0nxm,
I have checked the Philco Library, and though I can find Part Numbers for the speaker and output transformer I can't find impedances either.

Below is a link to the official Philco documentation.

https://philcoradio.com/library/download...-final.pdf

Common speaker impedances post war were 3.2 Ohms, 4 Ohms, 8 Ohms and 16 Ohms. I am going to hazard a guess that this set, like most AA5 sets of the era used a 3.2 or 4 Ohm speaker. It is possible that the set used an 8 Ohm speaker. If you have other speakers that don't fit but you know the impedance, hook them into the circuit and see what happens. Car radio speakers can either be 8 Ohms or 4 Ohms, and the impedance is usually listed on the magnet. Moderately priced surround sound systems that came with the speakers usually use 3.2 Ohm or 4 Ohm speakers. If you have one, try that. Don't expect a lot of bass, but judge the amount of volume before distortion is noted.