Saving old vintage gear is a lot harder than people make it out to be.

@jmncbh 

I wouldn't say that you need to get proper measurements to find a replacement.  I would think the point of replacing the parts is to try and fix the speakers, making them sound as close to orginal as possible? 

And I wouldn't say your are too late in process....In your case, assuming that everything else in the speaker (drivers and crossovers) is ok, changing to polypropylene caps is going to change the sound.  So maybe the thing to do is replace them with electrolytic caps of the same values.  Yes, different manufacturers of caps will still have an effect on the sound, but I would think not as much as a change in cap type.

I have repaired or rebuilt several sets of speakers in my past.  From old Polk Audio Monitors (10's and 5b's), to 2 sets of Definitive Tech 10's, a set of 8's and am now fixing blown tweeters on a set of 6's, replaced panels on Martin Logan electrostatics, repaired the crossovers on Magnepan MG12s, and two different sub-woofers.  Most of the time there was a change to the sound I had gotten used to, because there was something wrong with the speaker.  Thus the reason to repair/rebuild them.   (Except for the MG-12's, which I accidently sat on the remote and turned the volume to max and destroyed the crossover.  It was ugly..sparks and smoke.... )

So don't loose heart.  Give the repairs a chance.  You may find that once you get used to the "fixed" sound, you might like it even more.

- Jeff

Thanks for the encouragement! I replaced electrolytic capacitors on my polk rt55's and loved the sound. I'm sure I'll be able to figure something out with the Eosones. I'm going to buy a number of electrolytic capacitors to find the best replacement for my tricky dipole speakers. 

@jmncbh 

The key is to take your time and be methodical about the process.  Don't make to many changes at once, don't get radical with anything (yet) and don't make any assumptions...test everything.  (Not getting any sound out of a speaker... make sure the cables are connected... and the amp is acutally plugged in...  oops...LOL)

And to the whole group... If anyone happens to have a schematic for the crossovers or know where he can get a copy, it would help.  I believe that Sandy Gross, who founded Definitive Technologies, was still at Polk at this point and may have been involved in the design of these dipoles.  If so, the rear drivers maybe crossed over at different points than the front drivers.  (As he did with some of the early models from Definitive.)

I replaced the new polypropylene capacitors with electrolytics that mimicked the old ones & the speakers sound amazing! 

Excellent.  Glad you are happy with them.  

Enjoy!