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keenone

KLH Model Seventeen Manufacture Date

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Welcome keenone. Nice speakers. I can't give  you an exact date but the Seventeens were manufactured 1965 - 1974. Considered to be among KLH's best 2-ways.

I'd recommend replacing the crossover capacitors. If you haven't done it before, it's not hard but those old caps are notorious for going bad.

Kent

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klh_17_brochure_p3-2.jpeg

klh_17_brochure_p4-2.jpeg

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Do you know where I could get the parts, and would they be original to the speakers? Also, they sound great, and my motto is if it ain’t broke don’t fix it. Is there a way to tell if the current capacitors have issues?

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Each speaker takes one 8uF cap and two 2uF caps. Partsexpress.com has them: https://www.parts-express.com/dayton-audio-dmpc-20-20uf-250v-polypropylene-capacitor--027-414 and https://www.parts-express.com/dayton-audio-dmpc-82-82uf-250v-polypropylene-capacitor--027-426  (8.2uF is close enough--well within tolerance) or if you want exactly 8.0uF, double up on these: https://www.parts-express.com/dayton-audio-dmpc-40-40uf-250v-polypropylene-capacitor--027-421

These are modern film caps, so not original to the speaker. Film caps last virtually forever but non-polar electrolytics (NPEs) like the originals last a couple of decades. Parts Express does have NPEs but most of us here use film  https://www.parts-express.com/cat/non-polarized-electrolytic-capacitors/1385

I should also mention, because it can be confusing, the 2uF caps in the original crossovers are double--two 2uF capacitors in a single case with one common (black) lead and 2 red leads. Just replace that with two 2uF caps. Also--don't worry about the voltage rating. I think the originals were 50VDC, modern caps will be higher. It's always good to go higher, never lower.

There is a way to check the caps but new ones are so cheap it's not worth it. 

Below is a schematic and a picture of a Model Seventeen crossover with an exploded capacitor.

17_SCHEMATIC copy.jpg

exploded.JPG

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wow, thank you for this info. So it sounds like it’s possible that my speakers could sound even better than they do now if I do this, but it will at least make them last longer, is that right?

I have not worked on anything like this before, but would I need to take the speakers out of the front to do this, or does the back panel come off? Honestly, I don’t even know how to take the front screens off which are in near perfect condition and I’m afraid to mess them up somehow. I assume I will need a soldering iron, is that correct?

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OK. A good introduction to speaker restoration is this: http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/restoring_the_ar-3a/  The AR-3a is bigger and more complex but some principles are common to all speakers of this era. Here's a thread on Seventeen restoration: https://community.classicspeakerpages.net/topic/11067-another-seventeen-restoration/  You can also search through this forum for Model Seventeen (or the essentially identical Model Twenty) restoration.

 

Your grilles are attached with Velcro, so they'll pull right off. Next remove the woofer by removing all the screws. There is putty sealing the woofer to the cabinet and it may have become rock hard so it could be tough to remove. Pull the woofer out and you'll see the 2 wires: red & black. These are connected with wire nuts. Remove the wire nuts.

There is a piece of crinoline-like cloth behind the woofer. This keeps fiberglass out of the woofer. Remove that and set it aside. Next, wearing gloves, pull out the fiberglass and store it in a plastic bag. This will reveal the crossover. 

What you want to remove is the 2 black capacitors with red ends. One, the 8uF is a single and you can just the 2 wires and splice in the new cap. You can solder it or use crimp connectors.

Now look at the double cap. It has a black wire coming out of one end and 2 red wires coming out of the other. Take your two 2uF caps and twist one lead from each together so you now have one lead at one end and two leads at the other. Use this to replace the double cap. Just make sure you locate the caps somewhere so the metal leads don't touch any other metal. 

Then put it all back together in reverse order. Make sure to get that crinoline in there to protect the woofer. And you will need a seal between the woofer and the cabinet (like the old putty). The best stuff is foam gasket from Parts Express. https://www.parts-express.com/parts-express-speaker-gasketing-tape-1-8-x-3-8-x-50-ft-roll--260-540  But you can also use duct seal, available from Lowes or Home Despot https://www.lowes.com/pd/Gardner-Bender-16-oz-Duct-Seal/4595233?cm_mmc=shp-_-c-_-prd-_-elc-_-google-_-lia-_-106-_-electricalaccessories-_-4595233-_-0&placeholder=null&&ds_a_cid=112741100&gclid=CjwKCAjwkoz7BRBPEiwAeKw3qyzqFfPAGbogQPlvT0WG693ZafxEHlZPiQxLfA5aaoc4s_6t4onK_RoC-_oQAvD_BwE&gclsrc=aw.ds  The idea is to make the speaker air-tight. After it's finished you may want to use Roy's sealant on the woofer surround, but that can wait.

Kent

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Thank you for this detailed info, I will order some parts and try this. Do you think a high quality silicon for windows and such, for example GE silicone would work to seal the woofers?

I’ve use this silicone on many things like my home’s sunroom glass panes, and have been blown away at how long it stays soft and leakproof even under direct sunlight, rain and weather...for years.

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I wouldn't. The foam gasket tape creates a good seal but the woofer can be removed easily if needed. The duct seal is less convenient but still lets you remove the woofer. You tear off a chunk and roll it out to make a snake like you may have done with plasticene "modeling clay" as a kid. GE Silicone will hold it tight and make it difficult to remove.

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