• Check out the Annual AK Secret Santa exchange Program, signup before November 23rd in the AK Charities & Christmas forum!

KLH Model 6 Restore

cosme said:
I just procured a pair of Model 6's as well...The tweeters aren't working but I also suspect that it might be a cap issue. ...I didn't apply to much force when trying to remove my grill covers, thinking they might be one of the early runs that were epoxied in..... Serial number begins with 0032XXXX.
Click to expand...

@cosme

I concur with @GD70 in his post above about permanent grills, however no need to take them off as you'll have to go in the back of the speaker in order to access and replace the caps.

This recent tutorial (see the link to his detailed pics) is spot on and what you can look forward to

https://www.audiokarma.org/forums/index.php?threads/klh-model-six-recap-tutorial.936285/

Another way to verify if yours are indeed early model is by looking at the back

These are early 6's

tolXH3s.jpg

These are later model 6's

375036652.jpg

If you need assistance, have questions etc be sure to create a new thread
 
The Model Six (and others) were listed for sale as late as the 1977
HiFi Stereo Review Buyers Guide, p. 142. Whether they were actually
sold in that period, I don't know, but it doesn't make much sense to list
something not for sale.

I rebuilt some Model Fours with the epoxy potted crossover. It saves
a lot of mess to mount them with crossover side down, on saw horses.
Then all the chips fall out of the box, not in it.

Watch the terminal insulators on the crossover plate...

mounted3.jpg
 
87B04C20-9930-4784-A9C4-D722A13012CF.jpeg 13651BDB-B475-4235-9C91-D9A709923560.jpeg 7B8286C7-7DDC-46C4-945D-72A8A9533AA2.jpeg My 6s have serial nos 0611xx. Had to go through the back to recap. Here’s a pic of the 8 uF cap. I cut that cap out and then spliced extension wires so that I could install the new caps (2 4uF Dayton polypropylenes in parallel) outside the cabinet. I then hot glued them back in the cabinet. I soldered the connections and then slid some shrink tube over it but the tubing didn’t shrink enough! Thus I added some electrical tape. Looks horrible but nobody is going back inside these cabinets for a long time.

I mounted a square piece of Masonite to the back plate so that it fit snugly into the hole in the cabinet. The mess of resistors and tweeter increase/decrease capacitors was glued to this. I drilled holes in order to thread through the tweeter switch and binding posts. This whole thing was then glued in place with silicone and the nails reinstalled. The back plate is pretty solid.

The 6s sound fantastic. A true classic. Plus they really look really good.
 
Damn you're getting me all worked up now. Those look awesome; nice job. I bought 2 sets of 6's late last winter for 50.00 each set and they're just sitting looking at me crying as I haven't touched them.

1 set the Cabinets are in really good shape, but the other has much swollen area of the MDF from more than just moisture...had to be water. The enclosures to me are beyond repair. I'm thinking of using a pair of Sansui SP-2000 enclosures which are darn close to the same dimensions as a 6. Good idea or not?
 
Last edited:
Briarhill said:
Damn you're getting me all worked up now. Those look awesome; nice job. I bought 2 sets of 6's late last winter for 50.00 each set and they're just sitting looking at me crying as I haven't touched them.

1 set the Cabinets are in really good shape, but the other has much swollen area of the MDF from more than just moisture...had to be water. The enclosures to me are beyond repair. I'm thinking of using a pair of Sansui SP-2000 enclosures with are darn close to the same dimensions as a 6. Good idea or not?
Click to expand...
I’d say give it a go! Got nothing to loose, and you’ll have another set of great sounding speakers!
 
RxDx said:
The Model Six (and others) were listed for sale as late as the 1977
HiFi Stereo Review Buyers Guide, p. 142. Whether they were actually
sold in that period, I don't know, but it doesn't make much sense to list
something not for sale.

I rebuilt some Model Fours with the epoxy potted crossover. It saves
a lot of mess to mount them with crossover side down, on saw horses.
Then all the chips fall out of the box, not in it.

Watch the terminal insulators on the crossover plate...

mounted3.jpg
Click to expand...
Saw horses! Brilliant!
 
Awesome thread and very timely; I'm looking at a pair of early 6's with bare birch cabs. Why would they sell bare cabs? Were they intended to be mounted in larger custom enclosures?

Confused on the front panels: By "knocking out the panels" from the back with the crossover-cover off, I assume you are knocking out just the grille panels? If they are bonded in, don't you do some damage by knocking them out?
 
Forgot to ask: If the early versions had non-removeable grilles, how was the re-doping of the surrounds supposed to be accomplished? Was this NOT intended to be a maintenance item by KLH?

For us 50 yrs later, what is the method of re-doping? Does this kinda force you to open up the back?
 
My Sixes came with their original boxes. The finish on mine is flawless, but yours look as good or better. I put in new caps and redoped the surrounds. I plan to keep these.
 
b-rider said:
Awesome thread and very timely; I'm looking at a pair of early 6's with bare birch cabs. Why would they sell bare cabs? Were they intended to be mounted in larger custom enclosures?

Confused on the front panels: By "knocking out the panels" from the back with the crossover-cover off, I assume you are knocking out just the grille panels? If they are bonded in, don't you do some damage by knocking them out?
Click to expand...
There is a thread about this somewhere here, but the entire baffle was knocked out by hammering on a board placed through the rear opening. It sounded crazy to me but it's a thing. And it worked. If I can find it I'll post a link.
 
b-rider said:
Awesome thread and very timely; I'm looking at a pair of early 6's with bare birch cabs. Why would they sell bare cabs? Were they intended to be mounted in larger custom enclosures?
Click to expand...

Lots of good speakers back in the day were offered in an unfinished option. KLH 6s were one such speaker. Also Most of the vintage Acoustic Research speakers could be purchased finished in bare pine. People would paint them so that they could be placed in a bookshelf or mounted on a wall such they they'd blend into the decor. Different times for sure.
 
b-rider said:
WOW is right, so the grille panel IS the panel that the drivers are mounted to. From an engineering and manufacturing perspective, all I can think of when I think of a smart man like Henry Kloss is "What the heck was he thinking?".
Click to expand...
Yes, that’s the general consensus! But I’ve said many times, the epoxy mounted woofers go a tad deeper than the screw mounted because the excursion is longer. I’ve had both.
 
He originally thought, apparently, that cast aluminum was the way to go,
on the first four models. Then the epoxy-mounted versions, then the
stamped frames. Sixes never got the cast woofer, AFAIK.

This is a woofer from a Model One, serial # 002.

front.jpg

side1.jpg

side2.jpg
 
Don't know about costs, but AR used cast for a number of years, way longer
than KLH. My memory is it was until AR was sold in '67, but I haven't verified it.

As far as ol' 002, maybe someone will want it bad enough for historical reasons :-)
It's not in rotation now. I don't have room for it in my office, so it sits in the test bench
in the basement. I'd also like to get the Janszen 1-30s restored.
 
Guess I'm still a newbie to this hobby, but I've never heard of a cast speaker housing. I guess a steel stamping requires a tool just like a casting, but in my line of work a cast aluminum part costs waaaaaay more to produce than a formed steel part.
 
Castings have to cost more. Pouring molten aluminum into molds requires lots of time, energy, labor, and expensive raw materials. Stamping a bunch of thin, flat, cheap steel blanks into baskets must cost pennies by comparison. Every step is cheaper and faster. IMO.

But that 002 woofer that RxDx has is real neat.
 
Last edited:
How have people removed the toggle switch screw from the back panel?

I have a spanner wrench exactly like this one but it refuses to budge.
 
You must log in or register to reply here.
Back
Top Bottom