Working on a pair of KLH Model Twenty Three - help me out.

Brett a · Jan 29, 2013

Hi all.

I picked up a pair of KLH Model 23s recently. They are assumed to be all original. They work well, but I want t o recap them so I am getting more of their original performance.

I'm planning on changing the caps, De-Oxit-ing the selector knob and maybe re-doping the cloth surrounds.

Can anyone point me to info on re-doping? I've done some reading on line and it seems like it could take a very long time to get a clear picture of the world of KLH doping. Can anyone point me to a primer?

Any words of wisdom before I pick up the screwdriver and soldering iron?

I'll post pics later.

bluescat · Jan 29, 2013

Hi: Go to ebay and search for "Vintage AR" they sell a compound that worKs very well. It takes about 3 coats of the compound they sell over a period of about 5 days. I did a pair that I have owned since 1972. I can't say that I noticed a great deal of improvemet, but more importantly, they don't sound any worse. I wouldn't cheap out and use caulk or gasket cement which I'm sure someone will reccomend These are nice speakers don't ruin them.JMO

GD70 · Jan 29, 2013

Yup, good stuff. I used it on my 6's. After all these years, more than likely, they are not air tight anymore.

There's several current threads on re-capping KLH's. Do a search.

I did mine with help from several AKr's and specialidiot's restoration thread.

Glenn

89grand · Jan 29, 2013

Most seem to suggest not attempting to redope the surrounds. It's probably extremely difficult to get them exactly back to factory specs and I can't think of a good way of measuring to know if you did, and if you are off enough, you'll change the woofers Fs, and generally the speakers overall sound. If you are off, I doubt there is any way to reverse what's been done.

I guess in a nutshell, I'd leave them be, and I did with the pair I had for a while. I just replaced the one simple cap in each crossover.

gbroot · Jan 29, 2013

Brett a said:
Hi all.

I picked up a pair of KLH Model 23s recently. They are assumed to be all original. They work well, but I want t o recap them so I am getting more of their original performance.

I'm planning on changing the caps, De-Oxit-ing the selector knob and maybe re-doping the cloth surrounds.

Can anyone point me to info on re-doping? I've done some reading on line and it seems like it could take a very long time to get a clear picture of the world of KLH doping. Can anyone point me to a primer?

Any words of wisdom before I pick up the screwdriver and soldering iron?

I'll post pics later.

I have 2 pair of 23'S. Great speakers after recapping and way better after redoping. +1 on compound that Vintage AR sells on Ebay. It is very close to the original. Easy recap. Only 1 4uf per cabinet. Dayton 1% or 5% grade from Parts Express will do the trick.

Brett a · Jan 29, 2013

Thanks everyone I'll check out the AR dope and do more reading.

The 1% Daytons arrived in the mail today. I may start in this tonight.

audiojones · Jan 29, 2013

89grand said:
Most seem to suggest not attempting to redope the surrounds. It's probably extremely difficult to get them exactly back to factory specs and I can't think of a good way of measuring to know if you did, and if you are off enough, you'll change the woofers Fs, and generally the speakers overall sound. If you are off, I doubt there is any way to reverse what's been done.

I guess in a nutshell, I'd leave them be, and I did with the pair I had for a while. I just replaced the one simple cap in each crossover.

Good advice IMO. The flexibility of the woofer surrounds is more pertinent than having an absolute 100% airtight seal around them in regards to bass response. If they sound good I'd recommend just leaving them be, but If you must seal them then do use the correct sealant sparingly as recommended by Roy C (he developed the stuff that Larry sells at vintage AR).

BTW - it's a good idea to rotate the woofer 180 degrees when re-installing it. Also, toss out that old foam sealing ring and use electrical putty or rope caulk to re-seal the woofer to the cabinet. That's where you want to make sure you have a 100% airtight seal.

Brett a · Jan 30, 2013

audiojones said:
BTW - it's a good idea to rotate the woofer 180 degrees when re-installing it. Also, toss out that old foam sealing ring and use electrical putty or rope caulk to re-seal the woofer to the cabinet. That's where you want to make sure you have a 100% airtight seal.

Fantastic! Thanks for the tip.
:thmbsp:

Brett a · Jan 30, 2013

So, I got into one of them this morning and tis is what I found.

The Patient:

Disrobed:

The Patient's ID card:

A suspect organ:

The operation begins:

What's going on here, this patient isn't sick at all!

Brett a · Jan 30, 2013

Looks pretty healthy, no?

Just to not leave any part out:

JohnMac · Jan 30, 2013

Did you install the caps or were the already in there?

They appear to be in exceptional condition inside and out.

John

Brett a · Jan 30, 2013

JohnMac said:
It looks like they've been recapped. You're good to go!

They appear to be in exceptional condition.

John

I see that!

I have to wonder who's work this is. It's got to be someone here.

I know they passed through Markus' hands at some point.

kirk57 · Jan 30, 2013

The surrounds look OK to me. If the butyl had flaked off it would just look like open weaved cloth.
So there are new caps, and the surrounds look good, so a shot of de-oxit on the switch is about all you can do.

How do they sound?

Those are nice looking. IME KLH always used pretty good quality wood for their cabinets.

audiojones · Jan 30, 2013

Yep, looks like someone knew what they were doing there. Everything looks great right down to rotating the woofers 180 degrees and sealing them up with electrical putty. If you were in NJ I'd almost swear that this was a pair I did, but I don't think any of 'em have migrated up to Mass.

Brett a · Jan 30, 2013

They sound quite nice considering they're probably 40 years old and can be bought for a modest sum now-a-days. I'll write more later.

One bummer is that having had more time to listen to them with different types of music, I've detected a very slight wooly rattle in one of the tweets. It's not there all the time (or at least I can't hear it all the time).

Some shots taken a few minutes ago. They are playing Jessica Williams' Live at Yoshi's at the moment.

:thmbsp:

GD70 · Jan 30, 2013

Brett a said:
Thanks everyone I'll check out the AR dope and do more reading.

The 1% Daytons arrived in the mail today. I may start in this tonight.

Cool! Post pics of your progress.

On the dope reseal-I applied 3 coats, and noticed a big improvement in the base response. One woofer was popping at high volume (voice coil bottoming out) and adding the 3rd coat seemed to help this some. BTW-the jar from AR is just enough for 3 coats.

When you push the woofer in, you want the woofer to spring back slowly, 1/2 second or so, not spring back as fast as you remove your fingers.

Glenn

michiganpat · Jan 30, 2013

rattle in the tweet? sounds like it's time for a KLH23 econowave

Brett a · Jan 30, 2013

michiganpat said:
rattle in the tweet? sounds like it's time for a KLH23 econowave

Tell me more!
:scratch2:

motorstereo · Jan 30, 2013

After seeing some of the great gear that you've been through I was thinking they wouldn't last too long with you either.
I've also had the 5's, 23's, 12's, 17's, and 24's. They're all gone now. They may have been great speakers in their time but you really don't have to look too hard to find something a lot better in more modern speakers.

Brett a · Jan 30, 2013

motorstereo said:
After seeing some of the great gear that you've been through I was thinking they wouldn't last too long with you either.
I've also had the 5's, 23's, 12's, 17's, and 24's. They're all gone now. They may have been great speakers in their time but you really don't have to look too hard to find something a lot better in more modern speakers.

I kinda' figured. I just wanted to see for myself. And have a pair of classics on hand should the need arise.

Working on a pair of KLH Model Twenty Three - help me out.

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