I'd visually inspect them. I assume that a quality speaker this will have polypropylene capacitors which should be fine, electrolytics would be pretty much at the end of their life by now (if there are any electrolytics they'll be in a metal can and usually have a cross indented in the metal). If you're unsure what you're looking at just google the text written on the component. I did read somewhere that the resistors are located close to the caps on this particular crossover and may have caused heat damage which would be worth checking for, a heat damaged PP cap will be pretty easy to spot.
Sonic effects of 20+ year old crossover capacitors?
I was watching those brief PS Audio YouTube videos and Paul talked about how the capacitors in speaker capacitors dry out over time and after 20 or more years, he suggested spec’ing the same rating of capacitors and replacing them.
Now I have Thiel CS 3.6 speakers being driven by Bryston electronics and man they sound good. Could be better though. How I know this is just by how revealing they are of changes in any part of the system. I’m getting some veiled vocals, and muddying of background vocals. I still get some treble glare which I understand is remedied mostly by better (able to drive lower impedences) amplification, which my 4Bsst2 mostly handles. Bad recordings can still be unlistenable at times but I have found that as I have improved things, even the bad recordings are tolerable.
Anyway, I just sent an email to Coherent Source in Lexington about this exact issue for these exact speakers.
But I am asking, in general: for speakers older than 20 years old, how much freshening up of the sound can be anticipated by swapping in replacement (upgraded?) capacitors of the same specification? I don’t know how pricy this can get. I don’t even know what my crossover looks like inside of my Thiel or even how many capacitors are on the crossover. So if anyone has done this service and can testify to how the post-service audition sounded, I personally would love to hear about it.
Now I have Thiel CS 3.6 speakers being driven by Bryston electronics and man they sound good. Could be better though. How I know this is just by how revealing they are of changes in any part of the system. I’m getting some veiled vocals, and muddying of background vocals. I still get some treble glare which I understand is remedied mostly by better (able to drive lower impedences) amplification, which my 4Bsst2 mostly handles. Bad recordings can still be unlistenable at times but I have found that as I have improved things, even the bad recordings are tolerable.
Anyway, I just sent an email to Coherent Source in Lexington about this exact issue for these exact speakers.
But I am asking, in general: for speakers older than 20 years old, how much freshening up of the sound can be anticipated by swapping in replacement (upgraded?) capacitors of the same specification? I don’t know how pricy this can get. I don’t even know what my crossover looks like inside of my Thiel or even how many capacitors are on the crossover. So if anyone has done this service and can testify to how the post-service audition sounded, I personally would love to hear about it.
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Had a pair of CS3.6 for over ten years. Loved them and wish I never sold them. Here’s a link that has the sales literature with photos. https://www.manualslib.com/manual/328007/Thiel-Cs3-6.html#manual also, join in the Thiel owners thread by jafant for valuable insight and help. |
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I'm recapping a speaker protection circuit on an amplifier right now. They do go bad, heat kills them faster, and very good capacitors (in DIY quantities) are cheap upgrades. Throw in some nice Mills resistors and you're golden. If you don't notice any change/improvement at all you still have the peace of mind from having high quality parts and you aren't out a fortune. |
Looking at the brochure provided by @bryhifi the caps look like polypropylene or similar. If you want to get to them you’ll need to remove the woofer and/or the driver above it which looks like a passive radiator (if it is then it won’t have any wires in the back so simple to handle). Once you’ve taken the screws out you may find the drivers have become attached to the gasket so may need a bit of coaxing out. Probably worth getting a few metres of neoprene gasket before you start in case it doesn’t come away cleanly. If you lay the speaker on its back and place a towel across the baffle you should be able to rest the driver there once it’s out so you can detach the wires... if you remove the passive radiator first that’ll give you space to rest the woofer. The picture on the top right of the brochure page 1 shows the resistors (white ceramic box shaped components) up close against the capacitors, that’s where I’d visually inspect for heat damage. It sounds daunting but it should be fairly straightforward if you plan it and don’t rush. |