I got 2 nice KLH model 17s speakers from my grand parents.
They are in pristine outside condition, but the didn't get any love since they were bought.
I'm not a expert in sound system restoration, but I knew that the capacitor were probably dead, even if the sound was still correct.
I scrapped the web and found this awesome thread on audiokarma. Unfortunately, the pictures disappeared some time ago. But hey, we got the wayback machine for that !
So if you don't want to read the whole thread, here is a little abstact of mine.
You'll want to do 3 things :
I live in France and found those here : Audiophonics - Dayton Audio Caps
The Dayton Audio were recommended on the AudioKarma thread.
The original thread says that you need only 4 2.0uF and 4 4.0uF. The reason is that the original poster in the audioKarma thread could not find 8.0uF caps and wired two 4.0uF in parallel. I did found the 8.2uF, which is close enough !
Concerning the 2.0uF caps, it seems my speaker revision was a bit different. I found a "Temple 2+2uF Black common" cap in both my speakers. I tested both caps, and they consistently read 3.6uF on both exits. So I decided to stay close to those values. You should open one of your speakers first to check the exact value of your caps !
The thread mention that instead of using "foam" around the speakers, KLH and Audio Research used cloth. Being sealed speakers by design, you should ensure that the cabinet stayed sealed! The cloth gets dry and permeable, reducing the sealing. People on the thread recommended this: ACOUSTIC RESEARCH SPEAKER CLOTH SURROUND WOOFER SEALANT KIT, ALSO KLH from vintage-ar seller on eBay.
BTW : To check if your cabinet is still sealed, that's quite simple : gently apply pressure on the woofer cone using both hand (carefully!). If the cabinet is not leaking the cone should take a second to smoothly come back in place. It's probably not very noticeable the first time you try it, but you'll see the difference after applying the sealant.
Use a fabric cleaner you find a your local store. I know brands vary from countries to others, so in the US there seems to be "Woolite Foam Cleaner" while in France you may use "Vanish".
The beast before the intervention :
Gently open remove the grill, using a cloth to protect the cabinet :
There are six Velcro fixation points. One of them detached from the grill. Just glue it back.
Using a permanent marker, mark bottom and top of your speakers. It will be easier to put them back in the right position.
It is impossible to unsolder the cable from the tweeter. So I left both speakers cable untouched at first :
There is an acoustic filler inside the cabinet and a foam protection around the speakers to seal the cabinet.
Remove the foam, and then the filler wearing gloves and put the filler in a bag.
You can now see the wiring. Take pictures, and draw a wiring schematics.
Fortunately, the speakers wire are connected using little "plugs", there are meant to be screwed on the cables, so just unscrew to free the cables.
The cap thats between the cross-over and the tweeter is the 8uF capacitor.
I'm especially bad at soldering and cable management, but here's the final set up :
Apply the sealant on the woofer cloth and let dry for a while. You'll get instructions with the product.
Just keep the woofer safe from dirt, cause the Sealer gets sticky. Next day, it should look like this :
Clean the grill with the fabric cleaner.
Finally, screw back the woofer and tweeter, being very carefull while positionning the foam sealing.
And put the grill back :
That's it ! Your speakers are brand new !
I just added 4 little acoustic isolation pads under the cabinet, to protect the cabinet and my floor.
If you own another set of speakers, the guidethrough will be much the same. Just open the cabinet and check the caps to buy the right ones and don't put this sealer if it's another brand !
