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

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.

OP:

Honestly the issue I brought up is rare, but when it happens it really messes with people who don't understand why their new fancy caps made the speaker severely change character. 

It's worth doing a full impedance simulation for this reason.  Also helps you understand if your changes are due to changes in ESR or actually better sounding parts. 

Generally, 1990s electrolytics and before were a lot higher in ESR than today's versions, so that's also something to think about when renewing old speakers.

Erik

@erik_squires

Thanks for the info on the ESR differences. Always a good thing to expand my knowledge base on a (very cold) Monday morning. After doing speaker performance upgrades for decades, the typical unexpected sonic difference frrom cap upgrades has been overwhelmingly positive. But, checking the ESR will. now be on our checklist of standard practices.

@beercanshooter

I think there is more to consider here than good vs bad capacitors. Capacitors have gotten much better over the years, and you don’t have to spend $$$$ to get something that sounds MUCH better than the OEM parts. This also applies to resistors, coils -- even input terminals. Our standard practice is to yank all the OEM wire out of the box and replace with "audiophile" grade cabling. Chances are close to 100% that you have good cables from the amp(s) to the speakers. There’s a reason you selected these particular cables. Sound quality? You might see if you can find the same quality cable in bulk to use internally. This could be challenging due to size, availability, difficulty of termination, etc. Just do the best you can. If, the cable is 10 gauge, you might have to reduce the number of strands or conductors to get you at a workable 14 gauge, for example. Yes, even short runs (12") matter.

We’re not trying to paint a mustache on the Mona Lisa here and "mess" with the designer’s intent. Just getting things out of the way, that make them sound worse.

Interesting conversation. Have restored a few sets of vintage speakers. Always replace the XO caps. most of the time, don't even test them, just replace. 

Every time it has been a night and day difference for the better! It always opens the speaker up, more bass, cleaner midrange, highs star to sing. 

If you are worried about ESR, try to get caps that don't have a low ESR. Even a cap that might register correct value might have a super high ESR, telling you it needs to be replaced. My last set of speakers a couple caps were in spec, but ESR was about 1ohm. 

From my experience, new caps always read on the low side, old caps are either on the high side, or just at value. If you have a 100uf old cap reading at 100uf or over, it's most likely about done. 

If you are unsure, just do one speaker, compare to the old. if you don't like it, swap it back.