Should I replace the crossover capacitors in my vintage AR 3a speakers?

Only as a learning exercise.

Be careful replacing parts that are in parallel to the driver as the old parts may have ESR that is part of the design. That’s actually true for all caps and coils but the one’s in parallel can cause unexpected impedance swings if not kept.

If you go down this path I strongly encourage you to get an impedance test tool like this one from Dayton (as used by some mega brands) or you can build a free one and use Room EQ Wizard. The benefits of this vs. a single cap/coil tester is you use it to test the entire speaker as well as individual components. It will measure uF/mH as well as ESR/DCR. Measure the speakers before hand, and after to make sure all is well.

If things don’t work it’s an incredibly good diagnostic tool. It’s kind of easy to tell what broke, also you can plug the data into a tool like XSim or VituixCAD to do a full electrical simulation.

Erik, I appreciate your thoughtful answer. I wonder how many people have not thought this thru and replaced the old caps in a crossover just because it seemed like a good thing to do while they were refurbishing an old speaker and unknowingly did more harm than good. Definitely food for thought.

I always test new tubes when I receive them, verify matched sets, .... see where the signal strength is for new compared to my existing used tubes ....

often, the newer parts are tighter tolerances than the older parts, i.e. +/- 1%; +/- 2%; +/- 5%, even back to the 1950’s, +/-10% was fairly common

audible difference? I replaced my capacitors in my AR-2ax crossovers as routine, without testing. I bought standard stuff from Parts Express, the originals were never exotic, and the 3 way design is what sounds so good, the crossover simply diviying up the frequencies as needed for the chosen drivers, renewed woofer surrounds.

Now that I remember, a new capacitor was a dud, found out when the speaker didn’t work. Parts Express replaced it without question, pronto. You would have known before starting the work. I have a multi-meter but never learned how to use it.

You have level controls, to inspect, clean/keep or replace, one pair I replaced, one pair I restored

AR-2ax rehab

new level controls

I have some spare oem level controls a member here gave me, if you find the need

Wear gloves, don’t breathe removing the original fiberglas, new polyfill from Walmart.