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65Buick

KLH Model 6 restoration- no driver access

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I want to restore my KLH model 6 speakers, but cannot remove the grille cloth to remove the drivers (I understand that some of  the production techniques actually installed the drivers onto the board and also added the grille cloth prior to building the rest of the cabinet) Any suggestions on how to get these drivers out without having to cut the grille cloth? It looks like the miter joints on the back of the cabs are compound, so I'm hesitating cutting off the back of the cabinets. Any suggestions would be helpful. Thanks

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On 12/5/2017 at 11:20 AM, 65Buick said:

I want to restore my KLH model 6 speakers, but cannot remove the grille cloth to remove the drivers (I understand that some of  the production techniques actually installed the drivers onto the board and also added the grille cloth prior to building the rest of the cabinet) Any suggestions on how to get these drivers out without having to cut the grille cloth? It looks like the miter joints on the back of the cabs are compound, so I'm hesitating cutting off the back of the cabinets. Any suggestions would be helpful. Thanks

The KLH Six

If the grills are stretched tightly against the front molding edge and can't be removed by Velcro attachment, it's likely that the Sixes you own have the epoxied woofers, early versions.  Until the mid-1960s, KLH (Henry Kloss) developed a method for mounting the speakers by epoxying the magnet assembly to 1-inch electric-pipe conduit and then the pipes epoxied hard to the speaker's baffle board.

KLH_Four_Woofer_(07).thumb.jpg.890d5174ea18e3f9f89c6e2da4995477.jpg

Kloss_Patent_003.thumb.jpg.6a252ed56d459501f56c184ebc4bfe99.jpg

No removal here.  Ostensibly, this obtuse Kloss design method assured consistent quality control, "+/- 1.5 dB!"  In reality, this design nearly bankrupted the company (despite the huge success of the excellent sound quality of the original KLH Six) because of the problem of access for repair.  It simply couldn't be properly done out in the field unless one had extra grill panels, extra woofer cones/voice coil assemblies and so forth.  The speakers invariably had to be returned to the factory, and after the war-surplus, mil-spec crossover capacitor ran out, KLH began using a cheap capacitor "Synchro XP," known to fail after a few years.  Tweeters would go silent because of this failure (happened to the Model Four as well), and repair required the following:

1.  Cut the grill cloth down the middle and rip it out of the way.  The grill was wrapped around the front baffle board and stapled to the back side to keep it straight and taught.

2.  Once exposed, get the knife out again and literally cut out the woofer cone and surround, cut the lead wires and the spider assembly, rip out the cone -- good or bad.

3.  Reach in through the "hole" of the woofer, past the epoxied magnet assembly, and attempt to make repairs inside the cabinet in the "dark."

4.  Once all of this is completed, reverse the process with new cone, voice coil, spider, surround, new grill and black under-ticking, and you're there.

So, that is what you are up against if you have the early version.  Hope this helps.

--Tom Tyson

 

 

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Tom,

Seems that you have done some more Model 6's restorations since the last few and you have some photos. I would like to know if comprehensive repair instructions exist somewhere. If you do, please let me know. If not , I would like to pull all he information together so all of us KLH speaker lovers will have a place to go for needed information. Presently , I own two pairs of Model 6's. One is a 1958 model. The other pair has a removable grill.  They sound fantastic, but i imagine they will fail some day soon.

Thank you

Joe

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65Buick, Welcome to CSP.

Typically during a restore of early Sixes, you will want to refresh the sealant on the surrounds. Assuming that is your plan, you would need to cut the grill cloths to get at the surround. You'd could build grills to cover the front then or alternatively, some buy vintage grills on the big auction site for the later Sixes that were built in a more traditional manner.

Getting at the capacitors is done through the back plate. You'll need small hands, but it can be done. I did a set of early Sixes a couple of years ago. Its worth it. There are a lot of threads here and at AK about restoring such Sixes.

Btw, if you decide to reseal the surround - use only Roy C's goo. That's the only sealant that everyone swears by and I've been using it on all my KLH and AR restores. Anything else is risking permanent damage to the driver by stiffening the surround.

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Larry,

That was an excellent write-up. I've never attempted those but it's nice to know there's a roadmap.

Did you cut off the grille to reseal the woofers or leave them as is?

-Kent

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On 2/7/2018 at 6:20 PM, JKent said:

Did you cut off the grille to reseal the woofers or leave them as is?

This was couple years ago, but I took GD70's advice and found a pair of decent KLH 6 grills and cut the near perfect cloth and resealed with Roy's gue.  It did make the speakers sound better. The thing is I wound up with another pair of 6's  to get the grills. I was going to part them out, but they were way to nice so I restored and sold them with new 18 ct. lambswool grills

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