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KLH Model Six

B

Bad Andy

New Member
Hello, I have been lurking on this site for a while.

Recently bought a cheap pair of KLH model six speakers from Craigslist.

As expected, the tweeters are not working, so I am going to put in new capacitors.

I have read many threads on here, but all of the old ones look different than mine.

Pardon my ignorance, as I am not all too familiar with electronics wiring diagrams.

The capacitors in my old speakers (serial number 39925) have 3 leads coming off of the same end (two red wires and one black wire). The diagrams that I have seen show two 2.0 Uf capacitors connected to the three way switch. I have one capacitor that is connected to that switch.

Also the larger capacitor (mounted to the sound board) has three wires coming from one end and no wires from the other end. I assume this is the 8.2 Uf capacitor, but haven’t taken it out yet.

Also should I change out the three resistors? Or do I re use the original ones. Does the three way switch go bad, and should I replace it?

Thank you, and I apologize for the lack of knowledge.

EDIT - I didn’t mention it but my speakers are the old style epoxied in woofers and tweeters. Original grills are still in place, so not sure how to remove them without damaging them.
 
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The capacitors you have are 2 in one. If you read the old cap, you sill see it is marked 2uf x2 which means it is 2 caps in one. the black lead is probably the common and the reds are the individual caps. The other cap may be a 4uf x2 and they tie the 2 together to make 8 uf. If you could post a pic of the writing on the cap and the whole cap, that would be helpful.
 
Test the resistors. Those are wired in series with the tweeters. Measure the resistance directly at the tweeter to see if the voice coils are open. The pics are of my original caps that were in my KLH 30's which are very similar to the 6's. also is a schematic of the crossover in the 6's. The par# on the bag is what I used to replace the originals with. purchased from https://www.parts-express.com/ (no affiliation).20190216_074704.jpg 20190216_074714.jpg image_27519.jpg
 
Me thinks someone has been inside these Sixes. You mention they have the epoxied drivers and glued on grill. They should have the block of epoxy block behind the back plate. I'm curious how you viewed the existing caps. Did you chip through the epoxy?
 
The dual cap is just two caps in one body- common ground.
Make sure you reuse the insulators for the terminals so you
don't short out the amp.
 
Thank you. That is what I was thinking. It is making a bit more sense now.

The other speaker is slightly older with a serial number of 38002. Both are in pretty good cosmetic shape for their age. I bought them from the original owner. He thought they were from early sixties. Anybody know the years from 5he serial numbers?

Still not sure if I should replace the resistors. I am thinking maybe I should while I have it all apart.

Also, how would I reseal the speakers if the grills are securely fastened? Is there an easy way to remove the grills? They look in great condition, so I would hate to damage them.
 
It is extremely unlikely you can save the grill fabric. I've seen a case or maybe two
where the front baffle was pushed out from the back. Normally it tears up the fabric.
But it's not hard to make grill frames and recover them, or buy grills from the later
version Sixes (which fit fine).

It is also unlikely the resistors need replacement. But they're inexpensive if you really
want to go to the effort. You could also test them while things are apart.

I'm guessing they were made in 1960-61.
 
Update: been busy with other things the last few weeks, so getting back to working on this project.

In the process of desoldering and cleaning up the switch, I think I broke it. It now doesn’t want to move.

Anyone know what type of switch I can get as a replacement? Is it a on-off-on 2 pole switch?

Secondly, I am having trouble understanding the wiring diagram. I understand the center position on the switch goes to the tweeter (and 8uf capacitor). Can somebody help me understand the individual wire paths from switch position, through the resistors and caps. I am having trouble reading the diagram as they seam to all be connected and separate.

Thank you in advance for help.
 
Very happy. Switch works as it should.

Just a quick listen to make sure tweeters and switch work. Now I am going to seal it all back up, and maybe start on the other speaker.
 
Bad Andy said:
Very happy. Switch works as it should.

Just a quick listen to make sure tweeters and switch work. Now I am going to seal it all back up, and maybe start on the other speaker.
Click to expand...
Nice work. These are not the easiest to work on with the small hole to get inside.
Regarding sealing the woofer surrounds. This is a very important part of a proper restoration. AKer "simply nuts" removed the front baffles by loosing them from inside and pushing them forwar with the grill fabric attached. He managed to remove the grill fabric to access the the woofers for resealing. The dust caps also need resealing. He then re used the grill cloth, replaced the baffles and they look great, and he reports they sound great.
Your other option is to cut away the grill cloth, and get later model removable grills. I did this and they look great. The epoxy mounted woofers go a bit deeper than the screw mounted due to a longer excursion. The bass is sublime when sealed properly.
Glenn
 
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