KLH 23 Recent Purchase - Advise

MFGuy

Active Member
I just picked up a pair of 23's. I was originally looking for the 17 to complete my inventory of previously owned speakers. However, I had a chance to pick up the 23's locally at a reasonable price (by today's standards). I have been told that I should recap the crossovers and redope the woofers. I just sent away for the Dayton caps (as suggested in another thread) to replace the existing ones. The crossover repair looks easy because there is only one per speaker. I hope a DeoxIT treatment will mend the tweeter control. Then I will redope the woofers. I also hear that I should rotate the woofer 180 degrees. The cabinets are in great shape except for the bottoms. I'm not going to address that at this point. Should I replace all the sealant around the woofer? Any other suggestions or recommendations. Thanks.
 

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If you are talking about the foam gasket that originally sealed the woofer to the cabinet, only replace, if damaged. I re-doped my woofers and have regretted doing so, but everyone else thinks it's necessary. I would listen to them for awhile, to see if the bass is lacking. If you do re-dope, use the AR sealant only, and use it sparingly. JMHO
 
These are outstanding vintage 2 ways. Replace the caps. With the woofer surrounds, first do a simple test to see if they are sealed properly. Gently push in the woofer cone and let it go. If it returns slowly, 1-2 seconds, then they are good. If they return immediately, then they need to be resealed. Only use the sealer eBay seller vintage-ar sells, or contact AKer Roy C., directly, as he makes the sealer for vintage-ar. These are designed to have a good seal for the correct bass output, which is great when properly sealed. usually just one application of sealer is all that's needed. Keep in mind, after it dries, it's still very tacky, which is how it should be.
Every pair of KLHs that I've restored, needed the surrounds resealed.
Glenn
 
Thanks BC and Glenn. Do you know if there is a good how to video for resealing the woofers. I'm pretty sure they need to be resealed since they spring back in less than a second...definitely no more than a second. I've replaced surrounds on my Advents but this is totally different...just wondering.
 
Thanks BC and Glenn. Do you know if there is a good how to video for resealing the woofers. I'm pretty sure they need to be resealed since they spring back in less than a second...definitely no more than a second. I've replaced surrounds on my Advents but this is totally different...just wondering.
Hey,
Congrats on your Twenty Threes. When you order the AR goo it comes with small application brush. One light coat is usually enough. It's really up to your ears, Listen to them for a while, if you feel they need some extra LF response, brush on a light coat. The Twenty Three is one KLH speaker that I've had not had the pleasure of owning.
 
The Twenty Three's sound very much like the Six, but can handle more power as the Twenty Three woofer is the same as the Five woofer. Think a Six on steroids!
The sealer is easy to apply, just brush it on to the edges. Also seal the dust cap.
Glenn
 
Thanks Glenn, I was wondering about the dust cap. The only video I saw was pretty lame but did suggest I should do that, One or two thin coats I assume and does it matter if the speakers are out of the cabinets or not?

A Six on steroids...reminds me of my comment on my S2000. A Miata on steroids. I'll keep posting as I have something to share.
 
The woofers do not need to be pulled. Start with one light coat. Let it sit over night, and test to see if the cones return slowly. If they do, that's all that's needed.
KLH had a service bulletin that any speaker sent in for work, have the surrounds and dust caps resealed, regardless of how old they were.
 
The woofers do not need to be pulled. Start with one light coat. Let it sit over night, and test to see if the cones return slowly. If they do, that's all that's needed.
KLH had a service bulletin that any speaker sent in for work, have the surrounds and dust caps resealed, regardless of how old they were.
Yeah listen to Glen..KLH don't need too much to get back in fighting shape, I've had a few pass thru my hands.

The sealant is NOT meant to stiffen the surround - it's a seal that is supposed to block air from escaping the enclosure. As I understand it, that's what the "push test" is showing you - the trapped air inside the box is affecting the movement of the cone. It's called an air suspension or sealed box type of speaker. So don't overdo the sealant or your low freq response will suffer - only enough to get the job done.
 
OK, first cabinet is opened. I attempted to create a schematic of the crossover (I admit, this is the first I've ever done so please accept a novice's attempt). I've added photos to help. Also, I'm somewhat confused, is one or two caps required per speaker or only one (Dayton 4.0 4.0uF, 250)?
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OK, first cabinet is opened. I attempted to create a schematic of the crossover (I admit, this is the first I've ever done so please accept a novice's attempt). I've added photos to help. Also, I'm somewhat confused, is one or two caps required per speaker or only one (Dayton 4.0 4.0uF, 250)?
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Google search the crossover schematic and match it with what you physically find, it will help guide you. Good luck!
 
OK, first cabinet is opened. I attempted to create a schematic of the crossover (I admit, this is the first I've ever done so please accept a novice's attempt). I've added photos to help. Also, I'm somewhat confused, is one or two caps required per speaker or only one (Dayton 4.0 4.0uF, 250)?

Just one cap, a 4uF. The other device in your photos is an inductor. No need to replace that.

Yours have a different brand of original cap than mine did. Mine had the notorious Temple cap. In any case, any NPE this old needs replaced. I used a 3.9uF Clarity Cap PX bypassed with a 0.1uF Vishay Roederstein MKP1837 in mine.

Here's the before:

KLH_23_Crossover_Before.jpg


Here's the after:

KLH_23_Crossover_After.jpg


Easiest recap I've ever done, also the most obvious improvement. Getting that 50-year old Temple cap put of there REALLY opened up the highs.
 
I spent several days looking for a 23 schematic but couldn't find one. I've heard the 17 is the same but doesn't match what I have. MCM, also, my third resistor is an 6 ohm, 5%, 5w; yours is 6 ohm, 10%, 5w. I'm not sure that makes a difference.
 
I spent several days looking for a 23 schematic but couldn't find one. I've heard the 17 is the same but doesn't match what I have. MCM, also, my third resistor is an 6 ohm, 5%, 5w; yours is 6 ohm, 10%, 5w. I'm not sure that makes a difference.

You shouldn't need a schematic to recap your speakers. There is only one cap, the 4uF. Just solder the new one in the same place as the old one, and you're good to go. It's the only thing that needs replaced.

The 5% and 10% values are just the tolerances for the resistors. Yours is 5% and mine is 10%, but the resistance (6 ohm) and power rating (5W) are the same.
 
I know I'm getting a little to anal with this but since this is my first look at these speakers that someone else owned I just wanted to be sure no funny stuff was done to it. Thanks for your help.
 
Thanks BC and Glenn. Do you know if there is a good how to video for resealing the woofers. I'm pretty sure they need to be resealed since they spring back in less than a second...definitely no more than a second. I've replaced surrounds on my Advents but this is totally different...just wondering.

I've had a couple of pair of 23's. Great 2 way's! Sometimes there's a little confusion on what the "re-sealing " of the surrounds actually is. It is quite simple. The sealant solution already spoken of sold by vintage-ar comes in a small jar and he sometimes includes a small brush. You simply brush the sealant on to the surface of the cloth surround. Will take all of a couple of minutes per speaker. Apply a lite second coat 24 hours later. The surrounds become porous over the decades as the original sealant dries up and goes bye bye therefore as already stated air leaks through and can really affect the bass response and muddy's up the sound. Getting that old cap out of there is equally as important. The 6's and 23's among the best of the two ways of that era IMO. Congrats and enjoy!
 
I’ll put a plug in for the:
Parts Express Speaker Gasketing Tape 1/8" x 1/2" x 50 ft. Roll
I recently worked on some acoustic suspension speakers, and replaced the old driver gaskets with this stuff. Easy to apply and the Bass came back big time!
In any case ensure your driver to cabinet is sealed well for the rebound test.

I really like the 23’s, I restored my KLH 23’s and gave them to my sister. Unfortunately I can attest they can be overdriven. I’m in the hunt for new woofers now!
 
Gbroots advice in on the money. Besides sealing the surrounds, seal the dust cap as well. Look closely, and you'll see the original factory brush strokes.
Obviously, someone has already replaced the cap. You can replace it if you want to start fresh, but the cap in there now will most likely be good for many years.
I also agree, that they can be over driven so be careful with the volume knob. You'll know if yo did by the loud "POP" when the woofer VC bottoms out. It will take a lot though as these have the same woofer as the model Five.
 
Go with the surrounds and try them out, the cap is not old.
Glen got me started figuring out how easy these are to rebuild, and you don't have the ominous petrified Toffee slathered all over the crossovers.
My cap was bad and not my tweeter on my model Six thanks again Glen for getting them pumping again, been like five years.
Come to think about it when i bought these i had a pair of beat up model fives that i parted out and put the woofers in my model six cabinets and sold the six woofers.
Could explain why they sound more full bottom end than the new sixes i have.:dunno:
 
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Obviously, someone has already replaced the cap. You can replace it if you want to start fresh, but the cap in there now will most likely be good for many years.

I'd still recommend replacing the cap while he has them opened up. He can do better than that Cosmic NPE. There is no way of knowing how old that NPE is and any modern film cap will offer better performance and with only one cap per crossover, the cost will be minimal. The caps I used for recapping my Model 23s cost just over 5 bucks per speaker, plus shipping. And there are cheaper options available (Dayton 5% from Parts Express or Solen PB from Madisound).

The work is minimal (cut out old cap, solder new cap in its place) and would be a good first DIY recap project for the OP.
 
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