DaveD Posted December 11, 2008 Report Share Posted December 11, 2008 I have seen many photos on eBay of KLH woofers. Most of the photos show the tan cloth dust cap coated with the same black sealer that is on the cloth surrounds. My original pair if 17s was purchesed new in 1974. The woofer dust caps are the same material, but are not coated. The black sealer on the surrounds was unevenly applied and became leaky. I re-coated the surrounds with the modern latex based surround sealer and the bass came back.A second pair of 17s that I bought does have the black sealer on the dust caps. Should I put the latex sealer on my unsealed dust caps? Should this improve bass response even more? Link to comment Share on other sites More sharing options...
DaveD Posted January 6, 2009 Author Report Share Posted January 6, 2009 Over 60 views to my post but no replies. Hmmm. Alright, let's take a poll to determine if I have an oddball pair of woofers.If you have one or more pair of KLH speakers with woofers, do the tan colored cloth dust caps on the woofers have the original black sealer applied to them? Link to comment Share on other sites More sharing options...
JKent Posted January 6, 2009 Report Share Posted January 6, 2009 Over 60 views to my post but no replies. Hmmm. Alright, let's take a poll to determine if I have an oddball pair of woofers.If you have one or more pair of KLH speakers with woofers, do the tan colored cloth dust caps on the woofers have the original black sealer applied to them?Hi DaveMaybe no answers because we don't know I have 2 pair of 17s (1 restored, 1 waiting). Here are some photos. It seems KLH made some changes. The earlier 17s had black rear plates with paper SN labels. My SN 34835 has a smear of black goop on the dust cap.Later 17s had aluminum back plates with foil SN labels. My SN 084756 has a good coating of black sealant on the dustcap (the left speker in the pair shot) BUT the other one does not. Go figure. Maybe someone else knows what the answer is.Good luckKent Link to comment Share on other sites More sharing options...
Carlspeak Posted January 7, 2009 Report Share Posted January 7, 2009 I'm only speculating here a bit, but my experience with AR woofers is the early models had vented voice coils and thus didn't need to cool the VC with a porous dust cap. Perhaps a sealed DC helps with the bass response. What I don't know is whether the KLH woofers with sealed caps also have vented VC's. Kent's brown DC also looks sealed - just with a different colored sealer. Something is brushed on there from what I can see in the pictures. Link to comment Share on other sites More sharing options...
boreas Posted February 17, 2009 Report Share Posted February 17, 2009 The earlier 17s had black rear plates with paper SN labels. My SN 34835 has a smear of black goop on the dust cap.Later 17s had aluminum back plates with foil SN labels.That's what I thought too but the Seventeens I just picked up have black rear plates with foil S/N labels. Plus the S/N's are higher numerically than either of the ones in the photos you provided of yours: #119140 & #119254. You'd think they'd have to be lower than the one on yours with the silver plate.The woofers are both dated August 25, 1969 but there's no date on the tweeters. Not conclusive but an indication that these are fairly early examples.My brain hurts, Mr. Gumby! By the way, both dust caps on my Seventeens are doped, as with my 2 pair of Thirties, but not the pair of Twenty-Twos or Twenty-Fours.JohnPS: Speaking of S/N's, the ones on my Twenty-Fours are consecutive, #066747 & 066748. Sorta cool, I think, but I doubt it makes them more valuable. It's probably fairly common with speakers sold as part of a system, though I know that at least one pair of my Thirties was part of a system because I bought that system new in 1972 and they're not consecutively numbered. (Wish I still had it complete. I have no idea what I did with the TT/Rcvr console.) Link to comment Share on other sites More sharing options...
Carlspeak Posted February 17, 2009 Report Share Posted February 17, 2009 I have a KLH5 woofer I'm repairing now dated 1967 with a brown DC. It's not sealed. The VC is toasted and am replacing it along with a new spider. The VC was perforated, but the perfs were located just about were it's glued to the cone and thus not effective. Perhaps that is why the DC is porous. It's the only way to cool the VC. Yet it wasn't enough to save this one. Link to comment Share on other sites More sharing options...
boreas Posted February 17, 2009 Report Share Posted February 17, 2009 Perhaps that is why the DC is porous. It's the only way to cool the VC. Yet it wasn't enough to save this one. The dust caps that are sealed on the speakers in my possession aren't really doped up the way the one in Kent's photo appears to be. Rather, it's just sort of lightly swabbed with the black (butyl?) sealant. There's just the faintest indication of brush marks on them. Perhaps the one in Kent's photo was at some time redoped or perhaps KLH couldn't decide on the best approach to the subject. John Link to comment Share on other sites More sharing options...
DaveD Posted March 27, 2009 Author Report Share Posted March 27, 2009 Hi DaveMaybe no answers because we don't know I have 2 pair of 17s (1 restored, 1 waiting). Here are some photos. It seems KLH made some changes. The earlier 17s had black rear plates with paper SN labels. My SN 34835 has a smear of black goop on the dust cap.Later 17s had aluminum back plates with foil SN labels. My SN 084756 has a good coating of black sealant on the dustcap (the left speker in the pair shot) BUT the other one does not. Go figure. Maybe someone else knows what the answer is.Good luckKentI was under the impression that the aluminum terminal plates with black lettering were the early ones. This is because the pair of 17s that I bought new in 1974 from a high volume discount retailer (Illinois Audio) have the black terminal plates with reverse lettering. I think that 1974 should be considered late since they were introduced in 1964 or 65. I could be wrong (again) of course. Link to comment Share on other sites More sharing options...
JKent Posted May 6, 2011 Report Share Posted May 6, 2011 I have seen many photos on eBay of KLH woofers. Most of the photos show the tan cloth dust cap coated with the same black sealer that is on the cloth surrounds. My original pair if 17s was purchesed new in 1974. The woofer dust caps are the same material, but are not coated. The black sealer on the surrounds was unevenly applied and became leaky. I re-coated the surrounds with the modern latex based surround sealer and the bass came back.A second pair of 17s that I bought does have the black sealer on the dust caps. Should I put the latex sealer on my unsealed dust caps? Should this improve bass response even more?2 1/2 years later, here's the answer: Yes.KLH Service Bulletin #60, in our Library, tells service centers to apply butyl to the "skiver" (cloth surround) AND the dust cap:http://www.classicsp...bulletin_60.pdfBetter late than never? Kent Link to comment Share on other sites More sharing options...
Pbass4life Posted February 4, 2015 Report Share Posted February 4, 2015 Thanks Kent! Link to comment Share on other sites More sharing options...
RoyC Posted February 4, 2015 Report Share Posted February 4, 2015 Those of you using my sealant (also sold by Vinatge AR) need not waste it sealing dust caps. It is too expensive for that. The dust cap is not a moving part, so anything can be used to re-seal it...tacky gue, rubber cement, etc.Roy Link to comment Share on other sites More sharing options...
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