My wife recently brought home a mid-1950s RCA "New Orthophonic" record player, model 7-HF-5.

The player has three speakers-- a centrally mounted 6.5-inch main speaker, and two auxiliary 3.5-inch speakers pointed away from the main speaker's projection at 45-degree angles.

I am attempting to restore this record player to good working condition. I have replaced the tubes and the needle (not the easiest things to find) and now need speakers (which seem impossible to find) because the originals are busted. In fact, the main speaker is nothing but a metal frame-- the original either rotted away or was broken by abuse. The auxiliary 3.5s have a couple of small torn places in the cones and generally sound pretty cruddy.

I was informed by a home and car audio tech today that I certainly wouldn't be able to replace them with simple car audio speakers, even though the original units are the same size as some fairly common car audio speakers. He said the impedance would probably be all wrong and thus I'd run the danger of ruining the record player's vintage amplifier unit.

The tech attempted to check the impedance of my old speakers, but was only able to get a good reading off of one of the 3.5-inch units, which measured at 3 ohms. He said we could assume the other 3.5-inch unit would have measured the same reading, but he couldn't say for sure what the 6.5-inch unit would measure. He said if he had to hazard a guess, he'd guess it would come in at around 10 ohms because the two 3.5-inch units were chained off of the 6.5-incher. But he said that's just a guesstimate, and he wouldn't buy any replacement speaker based on that.

Does anybody know the ohms of the 6.5-inch speaker in these old record players? Or where I can buy replacement speakers for it?

I'm fairly adept at minor audio repairs-- I've replaced speakers for much larger enclosures used in live music performance in the past-- but when it comes to home audio stuff this old, I'm a newbie and need a little help finding good sources for repair parts, user manuals, etc. (FYI, I'm going to try to contact RCA about it, but I don't necessarily expect much help there since this thing is more than 50 years old.)