KLH Tweeter ID and Repair

[doctorolds]

I just purchased 2 pair of KLH Model 5 Speakers for a reasonable price, but I have mismatched tweeters and missing the KLH emblems on the grills in one pair though.

The person I bought them from gave me several tweeters that were bad and I decided to see if I could repair any of them. All of them read an open with a DVM so I decided to take the metal grill off of one for a closer inspection. I attached a picture that clearly shows that the wire going to the voice coil is broken. There is a M-12 stamp on the speaker and I would assume indicates that it is from a Model 12 speaker, but I would like an opinion from another member with a bit more KLH knowledge to verify that please. I also would like a recommendation on the best way to make the repair to the wire, I can either pull it closer together and solder it, or I could try to find another piece of similar wire and add it in and solder it for the correct length, any opinions here?

I have been reading about the KLH tweeters here on AK and I have determined that there are basically two groups as listed below (please let me know if this is incorrect)
KLH Model 5, 12, and 23
KLH Model 6, 17, 20, 30, and 33

The question that I have is there a method to determine what model they are by the way they are painted, unpainted, or any stampings?

Thanks for your input!

 

[boreas]

I can verify your grouping except for where the Thirty-Three fits. Given that it's essentially a bass reflex Thirty, I'd be tempted to group it with those. This is ONLY a guess.

As to paint vs. not, the only tweeters I've seen that were painted were in early Seventeens and Twenties. If my experience is any indication, then, painted would be incorrect for the Fives.

I've never known of a way to ID the two types definitively. Your hunch that "M-12" indicates a Model Twelve tweeter's a good one. I think the Model Twelve was the earliest model to use that tweeter so designating it that way would make sense. That being said, I just looked at the tweeters in my Twenty-Threes and they're unmarked.

There's a current thread here about restoring Model Sixes. A poster to that thread has had luck repairing KLH tweeters with that type of failure. I think he used Super Glue?

Anyway, that's what I would try. I'd try gluing both halves of the broken wire directly and securely to the cone, making sure I had a solid connection by attaching an ohm meter to the terminals while making the repair.

It's certainly worth a try. The worst that can happen is that you'd end up with a dead tweeter, just like you have now.

You really have some great speakers there. Congratulations and have fun restoring them!

John

 

[doctorolds]

I appreciate your reply boreas. The 5's that I have seen ALL have a silver grill as well as the flange/basket. The M-12's in my possession have a silver flange/basket and a black painted grill.

It would be nice if any current owners of the referred to models would indicate the colors of their tweeters, IF KNOWN TO BE ORIGINAL, maybe we could better determine a method of identification.

What are the colors on your 23's?

In response to repairing the wire I think that I am going to pull them together and solder them since super gluing them does not seem like a good idea to me. When I was in the USMC one of my MOS's was a Micro-Miniature Soldering Tech so I can handle the little wires.

These are the first KLH's I have purchased any I am looking forward to restoring them and giving them a listen. I need to get some of RoyC's goop from VintageAR and do the woofers as well as order the caps and refinish the cabs, all of the normal things.

 

[boreas]

My Twenty-Three tweeters are silver but, except as noted regarding the black spray paint, I've never found the color to be diagnostic. Some are silver and some are faintly gold in color. (anodized?)

I just did a Google image search for the Model Thirty-Three. There are shots there of Thirty-Threes with both silver and gold tweeters. This bears out my own experience. I've had Model Thirties that I purchased new in '72. The tweeters were the goldish ones. I've also had several pairs of Seventeens, not purchased new, but the earliest pair, first year production, had black tweeters and the other later pair had the silver finish. As you know, the Seventeen and Thirty use the same tweeter.

If your soldering skills are up to repairing that tiny wire, that would be the thing to do. Me, I wouldn't attempt it. My hands are still steady as a rock but my eyes are shot.

John

 

[boreas]

I just noticed that you said your tweeters have a silver finish with the grilles painted black. Do you mean that the circular grille glued over the cone is painted but the rest of the speaker is not? If so, that's a new one on me! I've never seen a KLH tweeter that wasn't either completely unpainted or completely painted.

John

 

[boreas]

I just noticed that you said your tweeters have a silver finish with the grilles painted black. Do you mean that the circular grille glued over the cone is painted but the rest of the speaker is not? If so, that's a new one on me! I've never seen a KLH tweeter that wasn't either completely unpainted or completely painted.

John

Well, I just found one like that. It's a completed listing on eBay for what's described as a Model Twelve tweeter. Never saw that before.

I also just found an image like that with a Google search. Almost all the images show unpainted tweeters but a couple show a tweeter with a black center.

John

 

[doctorolds]

John, I attached a picture of the M-12 I have, Model 12(?) for you. I have seen all silver, all black, or silver with a black grill. Maybe there is some sense we can make of it all. I have seen most of the 6's with all silver also, even though they have a different tweeter supposedly.

Here is a link to a Model 17(?) with the annodized finish you refered to: http://www.ebay.com/itm/1-KLH-Model...=&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

I am wondering if the better tweeter for the 5. 12, and 23 are rated at 5 ohms versus 4 ohms?

 

[boreas]

John, I attached a picture of the M-12 I have, Model 12(?) for you. I have seen all silver, all black, or silver with a black grill. Maybe there is some sense we can make of it all. I have seen most of the 6's with all silver also, even though they have a different tweeter supposedly.

Here is a link to a Model 17(?) with the annodized finish you refered to: http://www.ebay.com/itm/1-KLH-Model...=&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

I am wondering if the better tweeter for the 5. 12, and 23 are rated at 5 ohms versus 4 ohms?

That eBay listing has, as you'll have noticed, bad information regarding its application. I looked at the two current eBay ads for pairs of KLH tweeters. One has no app data and the other has bad data. All are the goldish color.

I emailed both sellers to find out which models these came from. Neither knew, even though one of the listings said the tweeters were working when the seller pulled them.

eBay

All these tweeters, regardless of application, are rated at 4 ohms. On all that I've measured, however, the actual measurements range between 4 and 5 ohms.

John

 

[GD70]

I just purchased 2 pair of KLH Model 5 Speakers for a reasonable price, but I have mismatched tweeters and missing the KLH emblems on the grills in one pair though.

The person I bought them from gave me several tweeters that were bad and I decided to see if I could repair any of them. All of them read an open with a DVM so I decided to take the metal grill off of one for a closer inspection. I attached a picture that clearly shows that the wire going to the voice coil is broken. There is a M-12 stamp on the speaker and I would assume indicates that it is from a Model 12 speaker, but I would like an opinion from another member with a bit more KLH knowledge to verify that please. I also would like a recommendation on the best way to make the repair to the wire, I can either pull it closer together and solder it, or I could try to find another piece of similar wire and add it in and solder it for the correct length, any opinions here?

I have been reading about the KLH tweeters here on AK and I have determined that there are basically two groups as listed below (please let me know if this is incorrect)
KLH Model 5, 12, and 23
KLH Model 6, 17, 20, 30, and 33

The question that I have is there a method to determine what model they are by the way they are painted, unpainted, or any stampings?

Thanks for your input!

I have the Model 6's that John mentioned.
I re-capped them and re-doped the woofers. Neither tweeter works. I hoped they would after the re-cap.
I did not pull off the metal grills, but I think I'll give it a shot after
seeing seeing your close-up pic of the broken wire. I could not see that through the grill. Mine are also the goldish color, no paint.

See the thread, KLH Model 6, any good?

BTW, what did you use to remove the metal grills?

Glenn

 

[doctorolds]

Glenn, I use a pearing knife for almost everything I do but it is always kept as sharp as a razor blade, but you can use a razor blade if you like. I simply position the blade at the proper angle under the sealant and go around the outer potion and then I hold it at a 90 degree angle and go around the outside of the grill itself. That will loosen up most of it for removal, After most of the sealant is removed I use a small flat tip screwdriver and carefully stick it into one of the little holes in the edge of the grill and gently pry it up working around the whole speaker. After I lifted the edge of the grill up a bit I used the same knife and slid it below the grill to separate the rest. Have patience it it not too bad. Try not to bend or distort the edge of the grill much since it is rather soft and you will have to bend it back to the original position prior to assembly. There is actually a 90 degree bend on the very edge of the grill. The picture I attached should give you a pretty good idea on how I did it. Good Luck!

 

[doctorolds]

John, I found a reference to KLH speaker ID's on CSP at the following link: http://www.classicspeakerpages.net/...schematicsservice/klh_service_bulletin_59.pdf

I also attached some pictures of the tweeters I have. The first picture shows all of them, first two are unknown and all black, third one is the M-12, and the fourth is a Model 5 (I think). The second picture shows the M-12 next to the unknown tweeters and the third picture shows the M-12 next to a Model 5(?) I will have to take the tweeters out of my other pair to compare.

The Service Bulletin from KLH indicates that some Model 12's had an M-12 stamped into one corner of the frame. And it also notes that it used a different thickness for the top plate to secure the magnet. I think that it is thinner based upon the pictures that I have attached.

What are your thoughts on this? I also wonder what is on page 2 of that Service Bulletin since only page 1 and 3 are shown.

 

[boreas]

John, I found a reference to KLH speaker ID's on CSP at the following link: http://www.classicspeakerpages.net/...schematicsservice/klh_service_bulletin_59.pdf

I also attached some pictures of the tweeters I have. The first picture shows all of them, first two are unknown and all black, third one is the M-12, and the fourth is a Model 5 (I think). The second picture shows the M-12 next to the unknown tweeters and the third picture shows the M-12 next to a Model 5(?) I will have to take the tweeters out of my other pair to compare.

The Service Bulletin from KLH indicates that some Model 12's had an M-12 stamped into one corner of the frame. And it also notes that it used a different thickness for the top plate to secure the magnet. I think that it is thinner based upon the pictures that I have attached.

What are your thoughts on this? I also wonder what is on page 2 of that Service Bulletin since only page 1 and 3 are shown.

[EDIT] I just realized that the SB was talking about the top plate of the magnet assembly, not, as I was thinking, the flange. They're saying that's the way to tell a Twelve tweeter from the other similar tweeter. That's clear. BUT! Does the Five really take the same tweeter as the Twelve? That's the conventional wisdom here in internet land but the accuracy of that information will determine whether you have one correct and three incorrect tweeters or the other way around.

...........................................

Clearly, page 2 contains the answers to all our questions! That SB is pretty interesting and probably should go in my files somewhere.

Okay, here's what I think you have there. The two black ones are a pair. The only speakers I've seen painted completely black like that have been in Sixes, Seventeens and Twenties, all of which use the same tweeter. That's how I would tentatively identify those.

The pictures you provided don't allow me to see any difference in the thickness (gauge) of the top plates in your 4 tweeters. What I can see, of course, is that one of the tweeters has a substantially thicker magnet than the other three. I'm guessing that's your "M-12" with the black screen, right?

So, now what? As I said in another post, I've seen photos on the web of Fives with those black screened tweeters and I've seen photos of Fives that don't have them. That may mean that screen color is immaterial.

What is almost certainly "material" is that magnet. I'm now thinking that the size of the magnet is diagnostic. Thick magnet means Model Twelve and, if it's true that the Five uses Twelve drivers, also Model Five (and Twenty-Three?). Thinner magnet means everything else?

If what I've written above is correct, which it VERY well may not be, it looks like you have one correct tweeter and three incorrect ones.

How thick is that thick magnet anyway?

John

 

[boreas]

Okay, I just pulled a tweeter out of my Twenty-Threes. It has the thinner top plate. I base this on the photos doctorolds provided that show the top and bottom plates either side of the magnet to be of essentially equal thickness on the M-12 tweeter. My Twenty-Three tweeter's top plate is significantly thinner than the bottom plate, just as are the top plates on doctorolds' other three tweeters.

This brings up the possibility that the Twenty-Three should be grouped for tweeter type along with the Six, Seventeen, Twenty and Thirty. Unfortunately, it offers no insight into the correct tweeter for the Five. I've always read that the Five was basically a Twelve without the contour boxes, in a smaller cabinet but with all the same drivers.

Another possibility is that early Fives used the M-12 tweeter but later ones used the other type tweeter. The Five did undergo some changes over the years with the crossover going from a mares nest point-to-point wired XOver to a PCB type. Maybe the tweeter was changed then too. That could account for why you see photos of Fives with both the painted and unpainted screens.

Wish I knew!

John

 

[doctorolds]

John, I will deal with your statements in the order listed.

Are the 5, 12, and 23 tweeters the same? I wish I knew for sure. That is why I asked if there is a method to identify the different tweeters in my OP. We do know that some of the Model 12's had an "M-12" stamped into corner of the frame and we definitely know what they look like based upon my example and the SB.

I would agree with your statement about the 2 black ones being a 6, 17, or 20.

The top plates? I see you made an edit referring to the top plate and flange so I will address it below.

The color is not a factor in determining the model they belong to? We know that they come in all black, all silver, silver frame with black grill (M-12), and the goldish anodized ones. I am unsure of any except the M-12 as of now.

I also think that the magnet size/structure is possibly the key here. Let me better describe the photos in post #11. All described in order from left to right.

PHOTO ONE:
All black - unknown
All black - unknown
Silver frame, black grill - M-12
All silver - Model 5(?)

PHOTO TWO:
All black - unknown *** LARGER TOP PLATE ***
Silver frame, black grill - M-12 *** SMALLER TOP PLATE ***

PHOTO THREE:
Silver frame, black grill - M-12 *** SMALL TOP PLATE ***
All silver Model 5(?) *** SMALL TOP PLATE ***

**** THE THIN TOP PLATE INDICATES A MODEL 12 FOR SURE AND I AM UNABLE TO SAY THAT FOR A MODEL 5 SINCE I AM ASSUMING THAT IS WHAT I HAVE IN THE PICTURE. I WILL PULL MINE TOMORROW TO COMPARE ****

The overall size of the magnet is 3/4" for the all black unknown speakers and 11/16" for the M-12 and the Model 5(?). The 1/16" less is the difference in the thickness of the top plate.

I hope that another AK member will be able to some photos of there tweeters in known to be ORIGINAL. I am sorry I was not able to reply before your last post.

 

[chrisand4]

I just got a set of KLH sixes a couple of days ago. Neither of my tweets were working, so I checked them with a meter, both read as an open.

The first one was just as stated above, one of the tiny wires was broken. I soldered it together and glued it down, now it's working perfectly.

The second tweeter's wire was broken in a way that was irreparable. Now I have to find a replacement for it. I hope your repairs turn out better than mine.

 

[doctorolds]

Hey chrisand4, at least you saved one of them. Do you know if your speakers and drivers are 100% original? If so take some pictures of the tweeters and post them for a reference. I may have a replacement for you once I pull mine apart and see if they are repairable.

 

[boreas]

PHOTO TWO:
All black - unknown *** LARGER TOP PLATE ***
Silver frame, black grill - M-12 *** SMALLER TOP PLATE ***

**** THE THIN TOP PLATE INDICATES A MODEL 12 FOR SURE AND I AM UNABLE TO SAY THAT FOR A MODEL 5 SINCE I AM ASSUMING THAT IS WHAT I HAVE IN THE PICTURE. I WILL PULL MINE TOMORROW TO COMPARE ****ORIGINAL. I am sorry I was not able to reply before your last post.

So, the one marked M-12 has the thinner top plate, as does the all silver? If, as the SB says, the top plate thickness is determinative of tweeter type and that some[/] Model Twelve tweeters are stamped M-12 and the M-12 tweeters you have are the thin top plate type, then you have two Model Twelve tweeters and two of the other type (the black ones). It also means that my Twenty-Threes do indeed have Model Twelve type tweeters.

The SB says only that the top plates of the two types are of different thicknesses. The pictures are so poor from repeated Xeroxing that the plates aren't identifiable. I made the foolish assumption that the thicker plate was for the M-12 type since the Five, Twelve and Twenty-Three have beefier woofers too.

So, at least you have pairs of the different types. That means you have at least two that are correct.

I'll be interested to learn what's in the cabinets now.

John

 

[GD70]

Hey chrisand4, at least you saved one of them. Do you know if your speakers and drivers are 100% original? If so take some pictures of the tweeters and post them for a reference. I may have a replacement for you once I pull mine apart and see if they are repairable.

I'm also looking for a pair for my 6's.
I bought a multi meter tonight so I hope I have time to se what's going on, and pull the grills to see if my wires are also broken and repairable.
There's pics in my thread of the tweeters which are original as far as I can tell.

Glenn

 

[chrisand4]

Hey chrisand4, at least you saved one of them. Do you know if your speakers and drivers are 100% original? If so take some pictures of the tweeters and post them for a reference. I may have a replacement for you once I pull mine apart and see if they are repairable.

Yes the drivers are original, I'll get some pics up tomorrow. I also bought a pair of KLH 33's at the same time, all of the drivers work in them.

 

[chrisand4]

Got a pic of a 6 and a 33.