KLH Model 32 guts etc.

Justgotohm

Super Member
I was in Charleston earlier today and picked up a pair of KLH model 32's. They looked to be in nice shape so why not. I got them home and ran a low volume test tone, noticed some slight distortion in one tweeter at lower frequencies. Upon pulling them apart I tested the 4uF cap and it was all over the place so I'm hoping that was the issue. They have one coil tested at 1.92 mH and the one 4uF cap mentioned above along with a massive amount of fiberglass damping material. Here are some pics of the little fellas. I picked up a pair of RCA (Tandy) bookshelf speakers with the Linaeum tweeters most often seen in Optimus branded speakers. The terminal cups are worth $4 so in the truck they went. I grabbed a pair of JBL Control 1x as well. These are actually in excellent shape and will most likely replace the tired Rock partners in my shop. Nothing spectacular but some fun finds on the cheap. All of the insulation came out of one speaker.
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Well I am just tickled with my modest score. New caps, all connections cleaned amd checked, pulled the braid nails out and attached Velcro on all four corners for the grills, cleaned up and hit them with some Howard's, these look great and sound very nice hooked up to a Fisher 460. These are consecutive serial numbers too which is a plus, fun little speakers. I have a small Monacor integrated amp that may be a nice match for these at a friends cabin, suits the décor if the power at be agrees. We where literally having a conversation about getting some music in their place this morning.
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In the pile,
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Sweet! I still haven't pulled mine apart yet, haven't been in a rush as they still have some high end to them.

That said, did you play them for any length of time without the cloth and wire over the tweeters? I'd be curious as to what sounds are hiding under that cloth.
 
Yes it's a very bright/loud tweeter without the damping material. I have been playing them all night put back together. I'm pretty impressed given I'm using maybe 10 watts playing all kinds of music. The new caps made a huge diffrence, more so than any other speakers I have recaped. The values printed on the caps where 4uF 50v. One was shot out completely and would possibly have resulted in blowing the tweeter if I had just hooked them up and let it rip. The other cap was 4.7, I went back with Dayton 4.0 metal poly's 250v, 5% I'm pretty sure, these where both 4.08 on my meter, it's what I had in my stash O caps. I cleaned any contact points and used the wire nuts that where used originally. The tweeters where 6.3 amd 6.5ohm at the terminals. When you decide to recap the tweeters take a flat head and stick it under the edge of damping cloth under the wire screen next to the small staples. These pull right out very easily, I used my finger under the screwdriver as a pry point as to not scar up the cabinets. The cap is a one piece unit, wire and all from the speaker terminals to the tweeter. I just pulled everything out of both cabinets to make it easier and clean the terminals that had some corrosion. The woofer terminals and wire where soldered in mine but the drivers are all tied together with wire nuts so I pulled it out that way. I highly recommend replacing the cap asap, If you do, post your thoughts on the change. On one speaker I used the very small staples to reattach the material and screen over the tweeter. They are so small it was a huge pain so on the other I just used three staples from a standard staple gun with 10mm stainless staples.
 
I just picked up a pair of 32's and I can't quit listening to them!!! So from what I've deciphered, I should probably get them recapped or I could lose the tweeters??? I'd hate to do that, these things are fantastic!!
 
I suggest redoing the surrounds, it made a very noticeable diffrence in mine. I bought the solution from Vintage AR off eBay.
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If a cap has drifted much higher than its rating, that allows lower frequencies into the tweeter and could possibly damage it. In your case, if they both sound good the caps are probably working somewhere in the correct ballpark. If you keep them within reasonable limits power-wise I don't see how you would be in danger of blowing tweeters. That said, if you like them now, they are likely to sound even better with those ancient caps changed out. I fixed up a pair of these once and pretty much any speaker that age that comes into my place gets some new caps.
 
One of the caps in mine had lost all continuity, the other was off as well. I would absolutely recap your 32's the caps in mine are 4.0uf spend the extra $4 and use some Metal Poly caps.
 
This was the speaker that sat on my repair bench back in the 70s. I cannot tell you how many times these poor speakers were abused with offending amps, turntables and the like that I had on the bench for testing. Those speakers (and the trusty HK 330 receiver) were like Timex watches; "Takes a licking and keeps on ticking".

The only limitation from a performance standpoint is that they will go into compression rather quickly with lots of power poured into them. That is, there's a point where they just will not get louder no matter how much more power you give them. This would only happen in a large room and with lots of power or a lot of background noise they're trying to overcome. This isn't surprising given the size of the cabinet, of course.

Cheers,

David
 
Tried the Velcro on a set of 32's. I couldn't keep the grill centered.

The tweeters are hard to find, so don't blow it.

Nice speakers.

The surrounds should be resealed.

The small woofer has a pretty long throw.

Enjoy.
 
I personally wouldn't go above 40wpc as a recommendation, but having said that you could hook up a 100wpc amp and if you are careful not to crank them - they'd be fine. The 20wpc should be a good match though. Be kind to the tweeters because they are a bit hard to find as replacement parts (unobtainium). I had to search hard to get a pair for a set I gave away to a friend. We had paired a set of 32's with a 40wpc NAD 7000 receiver. They worked well with that combo.

I am told that the Model 31 is the same speaker, but with vinyl covering instead of real wood veneer - just in case you ever need parts.

These are small speakers, but the woofers have good excursion and for what they are - they have decent bass if you use the vintage AR sealer sparingly.... (Don't go heavy with the sealer because it will stiffen the surrounds and hurt the results.)
 
With any pair of speakers, 'how much power they can handle' is a different question from 'what kind of receiver do I need', as can be seen by the above post (40 and 100 wpc would both work). Even a 20 wpc receiver can blow tweeters if it's cranked up too high and begins to distort and clip. The main thing is to listen for that distortion and know when to turn the volume down.

Not that it's a worthless question to ask, but any audio system needs to be taken care of, whether the power ratings are well matched or not.
 
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