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Classic Story and a Question re KLH Model Six (6)

K

KeithTr

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Nearly 50 years ago, after hanging with a friend in his father's man cave (yes, they existed back then) with McIntosh Tube components and Klipsch Corner Speakers (the big ones) - I decided to build a Dynaco system and bought a pair of KLH Model 6 speakers with the proceeds from a few weeks caddying on the golf course (version 2). Get the Dynaco amp all together - great soldering project for a teen - hook everything up and one channel doesn't work. I'm beside myself, so I did the logical thing and went to the only high school senior that I knew who owned an oscilloscope. Two hours later, having checked almost every connection I did, we discover that one of the fuses *appeared* continuous but wasn't! Unbelievable.

So yesterday I pulled my original Model 6 Speakers out which had been relegated to a storage closet in the age of bluetooth AV receivers and built in speakers and connected them to an old receiver. One of the speakers worked nicely and the other you could barely hear. I figured, okay, let's read up - spent plenty of time reading about people replacing capacitors etc. Finally, with a nagging thought at the back of my head, I switched the speaker wires - one channel of the old receiver was blown. Unbelievable.

Now the question: These speakers are almost 50 years old. All components (woofer/tweeter) work though one of the woofer cones looks like the paper is starting to fray a bit. Should I go through the effort to replace capacitors and reseal everything? I'm confident in my ability to do the repairs, but is it worth really disturbing what exists now?

Thanks in advance...Keith
 
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Welcome to AK.

Yep. I would not hesitate in restoring those Model Six speakers. I am listening to a pair now that I recapped and redoped with the proper stuff from RoyC. They are fine speakers and worth listening to.

I have another pair of Model Six that is the original with the woofer epoxied to the baffle. I am deciding how best to restore this pair. I've also restored KLH Models 20 and 17.
 
Thanks for the quick response. Two further questions - is there a way to contact RoyC - he seems to be the sole supplier of the "acceptable" cloth surround dope? And my physics/electronics memory has long faded, but i seem to remember that resistors are directional. What is the correct polarity of the resistors if I should decide to replace those as well? KLH model 6 wiring diagram doesn't appear to identify polarity of terminals for version2.

Thanks! Keith
 
You can look up RoyC using the member search feature here and then send him a message. That is how I bought my doping compound. Or you can look for vintageAR on ebay. He sells the stuff RoyC makes.

It is the capacitors you need to replace, not the resistors. Since you know the history of the speakers, what is in there will be the original non-polarized electrolytic caps. I suggest using metalized poly caps, like Daytons sold by Parts Express. Search for crossover capacitors. There should be two each of 2 uF caps and one 8 uF cap. I used two 4 uF caps wired in parallel for the 8 uF cap. The voltage rating does not matter as long as it is greater than 50 V.

The resistors are likely fine and do not need replacement unless they look damaged or burned. Resistors are not polarized.
 
An iconic speaker and well worth the effort. TONS of threads here on AK devoted to them, how to recap, repair etc so you should have no problem getting assistance.
 
I just did a pair of 17's. bought the dope on ebay from vintage ar. put 2 thin coats on with a tiny bit left over. recapped with the basic caps from parts express, Daytons.
sound great now.
 
I saw the reference to cloth surround dope.
I don't know anything about this.
What can you tell me about it?
 
Hey Will ☺️ I'm not an expert but basically those cloth surrounds become porous over time and allow air to leak through, thereby defeating the purpose and performance of a sealed enclosure speaker. The doping compound reseals the material so no air can escape. However, I've read that not all compounds are equal and the one recommended in this thread is the right one to use.

If you search for doping or cloth surrounds you'll find a lot of threads about it.

Cheers!

-Steve
 
You can get the sealer directly from @RoyC by sending him a PM. I just received a bottle yesterday. You can also buy from Vintage-ar on ebay but it' a little more expensive there.
John
 
WillMeyer said:
I saw the reference to cloth surround dope.
I don't know anything about this.
What can you tell me about it?
Click to expand...

Hi Will - as a newbie to refinishing/restoring speakers, I can only tell you what I've learned by reading this and other forums. The acoustic suspension speakers (like old KLH, AR etc) required a sealed cabinet as part their design. The speaker surround (linking the cone to the speaker frame) is sometimes cloth, sometimes foam, etc. On the old KLHs etc, it was cloth and the factory applied a sealant to that cloth to prevent easy air passage through the cloth. The sealant was apparently a kind of butyl rubber compound in a solvent. Over a long time, the sealant dries out. You can ruin speakers by applying a sealant that tends to harden - it will change prevent the speaker from working the way it was designed and can change the frequency of the output. Everyone here seems to recommend a sealant based on the original formula which is sold by someone using VintageAR on Ebay as their moniker or member RoyC of this forum. Hope that helps!
 
nerdorama said:
You can get the sealer directly from @RoyC by sending him a PM. I just received a bottle yesterday. You can also buy from Vintage-ar on ebay but it' a little more expensive there.
John
Click to expand...
Also, Roy usually gives you a bit more in the jar. I do recommend if there’s leftover, store the jar in a zip lock baggie. It helps to keep the sealer from drying out over time. If it does, you just need to add a little toluene, mix it up and it’s good to go.
 
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I got to Model Sixes via a chance encounter with AR4x's. I got the AR's at a thrift store for $5, the cabinets were painted and there wasn't any labeling on them. I liked them a great deal and even moreso once I overhauled them. That lead to me reading endlessly about the whole East coast approach which I had sort of dismissed. The Sixes were said to be the epitome of Kloss' work.

I eventually found Sixes in their original boxes and paid $300 for the pair. I recapped and resealed them. I had them properly placed in a room and paired with a little EL84 tube amplifier and a tuner. They were great and occasionally sublime.

Last year I finished renovating a house and moved into it. Somebody dropped a TOTL 50wpc Panasonic solid state amp from the early 70's on me shortly thereafter. After repairing a fault in the power supply I hooked up the Model Sixes to it.

I could solder the speaker wires in place on this rig. It sounds that good. I A/B'd them with JBL L-96's, the Model Sixes won.

In short, the KLH Model Six is worth the time and effort to sort out fully.
 
Thanks, Pete - I know the feeling. I had been using a Sonos system installed over a decade ago in the pre-built speakers all over my house and one day decided to clean out a closet which happened to be the place where my Model 6 speakers had been relegated to storage. I was the original owner, having purchased them for $140 in 1976 (lot of money for a kid then). On a lark I hooked them up to a surplus modern Denon high end AV receiver that came with the house and remembered what I had been missing. Even without recapping or refinishing anything, the sound was so much better than what I had gotten used to that I decided not only to refinish and restore my Model 6's to perfect condition, but to look for another set of speakers for my office.
 
Been using a re-doped and recapped pair of Model 17s in my work room. I have been happy with them.
 
KLH Model 6! I just bought a pair this afternoon from the original owner. Late 60s, they told me. So far they have done very well on the Quadrophenia Test.

I haven’t experimented at all with placement. I have them about ten feet away, six feet apart, angled slightly in. Now I’m feet up, drinking a Bell’s Two-Hearted Ale, and subjecting them to the Wildflowers Test.

I do believe I have scored.
 
GD70 said:
Also, Roy usually gives you a bit more in the jar. I do recommend if there’s leftover, store the jar in a zip lock baggie. It helps to keep the sealer from drying out over time. If it does, you just need to add a little toluene, mix it up and it’s good to go.
Click to expand...
Are there detailed instructions as to how to seal the woofer anywhere?
 
iramegdal said:
Are there detailed instructions as to how to seal the woofer anywhere?
Click to expand...
It’s easy. The surround sealer is just brushed on, lightly, and also the dust cover. Seal it the driver to the cab can be done with multiple materials. As easy and inexpensive way is with air duct sealer. Get it at a home center store, ably
Ut 2 bucks for a block. Roll it to make long worms and push it down on the cab surface where the mounter mounts. Once mounted, surrounds sealed, gently push woofer cone in and let go. If it returns slowly' you’re good to go. If it bounces back immediately, recheck the seal around the woofer basket. Also, the surrounds might need a second light application.

Glenn
 
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