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Restored Model 17 Speakers


Norman Nicolai

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I just finished restoring my second set of KLH Model 17 speakers.

I refinished the cabinets, replaced the capacitors and speaker wiring, sealed the woofers with Roy’s Goo,  and replaced the binding posts using rubber grommets to isolate the posts from the metal back of the cabinet (Hat tip to JKent).

I did not replace the fabric on the grills. They were in pretty good shape and keeping them seemed to augment the vintage look.

Some before and after photos:

951A3FE1-2CCD-47BB-ABFD-6B1FA46CF268.thumb.jpeg.4af7439156cba7eb7af05c517c5fde63.jpegimage.thumb.jpg.0829aaae93d043c94c6566b06683b4d8.jpgEB96E267-11DC-4DC9-B3C9-072DA9A5A548.thumb.jpeg.0070afda8a8c49a35e00bd6dda96549d.jpegD6495E84-DEBA-4B73-87C3-6D4B9F1E2AAB.thumb.jpeg.e2669f0f24ed4159df658a35ce64b50d.jpegimage.thumb.jpg.89869ae2a4e3d02de6776c9ef6a33a1d.jpg

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  • 4 months later...

I am not an expert, more a newbie, and there are far more qualified people to answer this question on this forum, but since you responded to my post I will give it a shot.

From what I know, if you are blowing tweeters it's probably not the crossover in your speaker. It's more likely that your amp is clipping when driving the speakers at high volume. If it is always the left channel blowing the speakers, I think it is more likely that you have a problem in the left channel of your Sherwood tube amp.

Which Sherwood tube amp are you using, and have you had it checked out recently by a repair tech? I have a Sherwood tube receiver (S8000IV) which regularly drives a set of my KLH Model 17 speakers and have never had a problem, although to be honest, I don't drive them at particularly high volume levels.

Anyone else have a take on this?

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Yes I have the same model Sherwood and no, it hasn't been serviced in quite some time due to the pandemic. I do have a replacement crossover plate and awaiting a new original tweeter. I think the best route for me right now is to keep the volumes low and replace the old capacitor. I also see some cheaper newer tweeters to install into this classic cabinet  ( Replacement Speakers 4.25" Cone Phenolic Ring Tweeter T-135 (simplyspeakers.com) but im sure they don't sound nearly as good.

 

 

File_000.jpeg

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Norman may be right about the amp but regardless you’ll need new caps. Replace them all. IIRC it’s one 8uF and two 2uF per xo. 
Brand of caps doesn’t really matter. Many of us use the 5% Dayton film caps from Parts Express. They also have the phenolic ring tweeters and some nice foam gasket tape to seal the drivers to the cabinet.

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Both of those have to go. The one on the left is a double 2uF. Just treat it like two 2uF caps with a common connection at one end. The 2.2uF pictured is close enough. 50V is a minimum but you can use 100, 250, 400, whatever.

Also replace the 8uF on the right 

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I am having a little trouble doing this on my phone but if you check the parts express site, they have the 1% Dayton capacitor 2.0uF and the 5% Dayton 8.2uF

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JKent is absolutely correct, the caps in your Model 17 have to go. KLH made great speakers, but they were notorious for using inexpensive capacitors in their speakers that had a limited life span.

I was just concerned that you were going to recap the speakers and blow another tweeter somewhere down the road, and original replacements are becoming harder to come by as vintage equipment continues to be popular. BTW, if you replace the KLH tweeters with something else you will almost certainly degrade the quality of sound. JKent can confirm this because I think I learned this from him originally, but I believe that KLH used the same tweeters in their Model 6, 17, and 20 speakers.

Here are links to the correct capacitors to use at Parts Express:

https://www.parts-express.com/Dayton-Audio-DMPC-2.0-2.0uF-250V-Polypropylene-Capacitor-027-414?quantity=1&custcol_ava_item=027-414&custcol_ava_incomeaccount=General&custcol_ava_upccode=844632013737&custcol_ava_pickup=F&custcol_disableshopping=F

https://www.parts-express.com/Dayton-Audio-DMPC-8.2-8.2uF-250V-Polypropylene-Capacitor-027-426?quantity=1&custcol_ava_item=027-426&custcol_ava_incomeaccount=General&custcol_ava_upccode=844632013799&custcol_ava_pickup=F&custcol_disableshopping=F

You will need 2.0 uF caps and 1 8.2 uF cap for each speaker.

Here is a link to the Model 17 crossover schematic:

https://www.google.com/imgres?imgurl=https%3A%2F%2Fcontent.invisioncic.com%2Fq297684%2Fmonthly_2018_03%2F5aba012f97e2f_KLH17.jpg.4b79a7c3a0bb31057c01a1bc187162c1.jpg&imgrefurl=https%3A%2F%2Fcommunity.classicspeakerpages.net%2Ftopic%2F10716-klh-17-schematic%2F&tbnid=aoaQvTcdFT7ZGM&vet=12ahUKEwjqgP_o7vbuAhWTcTABHct0CNgQMygAegUIARCUAQ..i&docid=xTHYt_j3-V0dLM&w=640&h=335&q=klh model 17 crossover schematic&ved=2ahUKEwjqgP_o7vbuAhWTcTABHct0CNgQMygAegUIARCUAQ

Good luck, and let us know how you make out!

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