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1967 KLH model 5 refurbish (1967?)

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Last week I picked up a set of these highly regarded classics. I have never owned a set before but had a good deal of exposure in the 70's. As a matter of fact, my preferences for East coast sound speakers was that I was never too thrilled with Advent offerings even though they were hugely popular, I liked the KLH 5s well enough, but thought they weren't as smooth as the AR offerings which were easily my favorites.

With that being said I have been watching for a set of KLH somethings for a while and this set is what I finally pulled the trigger on.

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As you can see they are in decent shape for being almost 50 years old. Grilles are solid, fabric not ripped, badges in place, terminal nuts intact, dial pointers as well! There are some flaws to the cabs with some moderate edge separation likely form some moisture and a couple dings and slight veneer peeling on random edges. Not terrible, but certainly not perfect. For the price I paid it seemed like a reasonable concession.

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I am intrigued by a variety of things already with this set. The first being that the serials 005999 and 006006 being pretty close in progression, and would seem like low numbers in the grand scheme of things.

The first being the interior of the grilles. There is a layer of fairly thick, tightly woven fabric under the dress cloth. Here is a pic where you can barely see through it. If you look closely you can sort of see the rails of the chair these are propped up against.

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and curiously when I pulled the first woofer, this same cloth was used as a buffer between stuffing (fiberglass) and driver. I have scanned any number of other's rebuild and seems most have referenced the use of cheesecloth for this. My immediate concern is that this fabric on the grille will muffle the sound to a fairly significant degree.....thoughts?

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Upon taking apart the first I was surprised/disappointed? by the lack of the use of retainers for securing the woofers in place. Also, the sealant used by the factory, some mortite variation, seemed very thin. My impression over the years is that some manufacturers make cabinets and some make boxes. The use of wood screws instead of retainers makes me feel the KLH factory was not as focused on the "cabinets" as was AR. At least for this set.

Here is a not so good pic that shows some mdf compromise from this approach.

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and then there is this..

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Not too concerned by this, but I am already toying with the idea of re-orienting woofer mount and using some retainers. If you are interested in the actual screws that were used, here they are.

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I have to head out to work for now, hopefully will add to this post later this evening.

I will be looking for thoughts on these topics that I have raised, and of course will likely need some guidance as I dig in deeper.

Geoff

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Geoff, you never have mentioned how they sounded? Did you give em a spin?

Also, I grabbed JKents Cap list from the other thread. He helped me on mine as well.

Caps:
3uF
3) 4uF
16uF
25uF
Resistors:
5
6
10
2) 15

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Geoff, you never have mentioned how they sounded? Did you give em a spin?

Also, I grabbed JKents Cap list from the other thread. He helped me on mine as well.

Caps:
3uF
3) 4uF
16uF
25uF
Resistors:
5
6
10
2) 15

Hi David et al,

Funny thing is I have not hooked them up yet. I fully expect them to sound like 50 year old speakers that need attention. This evening I will hook up the one I have yet to crack and will add my impressions after a quick demo.

As for the shopping list above, it would appear as my shopping list will be a little different. At least if I duplicate what is in there for OEM values! More on this later.

Geoff

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As for the shopping list above, it would appear as my shopping list will be a little different. At least if I duplicate what is in there for OEM values! More on this later.

Please check the caps carefully. As I said, the originals can be confusing because KLH used double caps in these--2 capacitors wrapped into one package, An in some cases a dual 4uF is wired like 2 separate caps while in others a dual 4uF may be wired in parallel to make a single 8uF. It threw me off at first but I'm quite certain the shopping list above is correct.

-Kent

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Please check the caps carefully. As I said, the originals can be confusing because KLH used double caps in these--2 capacitors wrapped into one package, An in some cases a dual 4uF is wired like 2 separate caps while in others a dual 4uF may be wired in parallel to make a single 8uF. It threw me off at first but I'm quite certain the shopping list above is correct.

-Kent

Hey Kent,

While I appreciate and respect your opinion greatly, I stand firm on my observation. I have seen the 2x4 red cap and that is not part of why I say this. In mine there is a 2uf piggy backing the 3uf and it is wired independently. Here at work I do not have pics of this, but I have checked and checked and checked. This does appear to be an anomaly.

Haven't done a complete resistor inventory yet but I will post some pics of this later this evening.

How about the extra fabric under the grille cloths? Is this to be found on other specimens?

Geoff

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Hey Geoff

Sorry. KLH and others made minor changes to things during production runs, so although the 4 or 5 Fives I worked on used the caps listed, I believe yours are different.

There may be a logic for going with the later xo. Presumably this was an improvement.

Virtually all classic KLH speakers had the sheer black scrim under the grille cloth.

-Kent

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Scrim you say. Was it commonly used as the buffer under the woofer as well? I wonder how much damping this material on the grille does to the sound?

So I am home and wanted to get a few more pics and observations posted. There are a couple of things worthy of noting. I have seen info about these speakers stating 1968 being the start of the run of the Model 5, but the dates on the drivers are from Nov. of 67' and the serial number is 6006! ?

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and then there is this

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which has a slightly different configuration. I am going to guess I should put a 4 where the 3 is and put a 3 where the 2 is. :unsure: The resistor shopping list seems to match up just fine.

Geoff

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things always look so much better after a little spiffing up

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Hi Geoff,

Looks like you have a great pair of speakers and a very nice project here. Your documentation is excellent and enjoyable to follow. I am no expert on KLH or AR speakers, but with regards to your dates, I have had a similar observation with a pair of early AR-6's. The AR-6 is purported to have been debuted in '72 or maybe late '71, but I have a pair (serial numbers close to 04000) which have driver date stamps from Jan 1971.

So, give or take a calendar year, it makes little difference. It seems you have obtained a very fine set of speakers.

Totally agree with you about the wood screws - - - that type of particleboard is particularly crumbly and certainly would be improved with a better machine screw attachment. Keep up the good work and great posts.

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I am going to guess I should put a 4 where the 3 is and put a 3 where the 2 is.

Nope.

That layout is exactly like mine. The 3uF is right. The 2x2uF is paralleled to make a 4. The 2x4uF is two 4uF caps. So you need to but three 4uF, one 3uF, one 16uF and one 25uF per speaker, See before & after below. They're from 2 different speaker sets but they're virtually identical. You can see the three 4uF and one 3uF clearly on the after shot (ignore the unnecessary blue "bypass" cap).

The cloth behind the woofer is like Kimpac in AR speakers--it keeps fiberglass out of the woofer.

I suspect the black scrim "may" muffle the HF somewhat. If I re-do KLH grilles I only use 1 layer but I would not recommend tearing apart good grilles.

btw--I don't see the rubber insulators on your speaker terminal posts. Did you take them off?

-Kent

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Hi Geoff,

Looks like you have a great pair of speakers and a very nice project here. Your documentation is excellent and enjoyable to follow. I am no expert on KLH or AR speakers, but with regards to your dates, I have had a similar observation with a pair of early AR-6's. The AR-6 is purported to have been debuted in '72 or maybe late '71, but I have a pair (serial numbers close to 04000) which have driver date stamps from Jan 1971.

So, give or take a calendar year, it makes little difference. It seems you have obtained a very fine set of speakers.

Totally agree with you about the wood screws - - - that type of particleboard is particularly crumbly and certainly would be improved with a better machine screw attachment. Keep up the good work and great posts.

Thanx Robert for chiming in. I very much enjoy this hobby and this community and thanx for the kind words. I am going to Woodcraft tomorrow with Diane and will look at fastener options.

Nope.

That layout is exactly like mine. The 3uF is right. The 2x2uF is paralleled to make a 4. The 2x4uF is two 4uF caps. So you need to but three 4uF, one 3uF, one 16uF and one 25uF per speaker, See before & after below. They're from 2 different speaker sets but they're virtually identical. You can see the three 4uF and one 3uF clearly on the after shot (ignore the unnecessary blue "bypass" cap).

The cloth behind the woofer is like Kimpac in AR speakers--it keeps fiberglass out of the woofer.

I suspect the black scrim "may" muffle the HF somewhat. If I re-do KLH grilles I only use 1 layer but I would not recommend tearing apart good grilles.

btw--I don't see the rubber insulators on your speaker terminal posts. Did you take them off?

-Kent

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Hi Kent,

I have the rubber insulators, they were removed during my eval of dis-assembly of speaker guts and I just haven't re-installed them.

I do understand the need for the Kimpac/scrim/cheesecloth behind the woofer. I have seen other model 5 rehab pics which show the cheesecloth looking product (Kimpac) for this purpose, not the dark colored scrim. I will do some eval once all back together and make some observations.

As for the caps, I am confused by your response. I sort of understand the red cylinder housing two separate 4uf caps, and the 2 x 4uf imprint helps me see that but the 2uf cap has no 2x2uf imprint and your reference to that is not sinking in.

Geoff

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Ha! I TOLD you they're confusing! ;) So it's not just me. I think I posted an incorrect parts list the first time I worked on these.

Look at the black "2uF" cap. It's just like the larger red one. There is one black wire (common) and two red wires. If it were being used as two 2uF caps the reds would be soldered to different points. But the 2 red leads go to the same point, so the two 2uF caps in that tube have been wired in parallel.

FWIW I have never seen black in a KLH either, Usually it's a white crinoline-type fabric. Maybe they changed the material they used or maybe someone has been in there before (the Mortite caulk looked pretty fresh in your photo. Usually it turns to cement after half a century). Kimpac btw is paper and kind of crumbly so I usually replace it with cloth such as crinoline. Allison speakers used fiberglass window screen (at least that's what it looked like).

Kent

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Re: woofer attachement, it'll be hard to improve on one of the very best details found in vintage AR cabinets - - - T-nuts. This pic is from that excellent AK thread on the restoration of rare KLH-28's.

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I will see what I can find tomorrow for some t nuts. Gonna be in Portsmouth and will likely have some clams too! yum :)

thought I would post more dating evidence before addressing the crossover

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M5 test?

267?

OK Kent, now I see it.....I think. I arranged the caps in such a way as to see more clearly the connections paths. What threw me is the red one being labeled 2x4 mfd and the 2 only being "labeled" 2 uf (not 2x2 uf/mfd). Then trying to understand the purpose? I can now see that the 2x4 red leads go to different points but the 2x2 red leads go to the same point. In both cases the black single goes elsewhere. Why would KLH do this? One red and a 4uf achieve that right? Which is the third 4 Kent, I get it.

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So the shopping list is certain. I have yet to do a listening test, and of course must test the drivers.

by the way, the Mortite was 50 years stiff. I don't think anyone has been in here.

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I can now see that the 2x4 red leads go to different points but the 2x2 red leads go to the same point. In both cases the black single goes elsewhere. Why would KLH do this?

I think they looked for the best buys. Rumor has it HK used to buy surplus parts on Canal Street in NYC. If they could save a few cents on caps they did. Makes it confusing for us though.

-Kent

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I think they looked for the best buys. Rumor has it HK used to buy surplus parts on Canal Street in NYC. If they could save a few cents on caps they did. Makes it confusing for us though.

-Kent

Probably no different than today's computer parts supply chain. Ever changing as suppliers come up with a deal for the manufacturers.

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Helpful note from Roy:

"I've found those KLH 5 (and 23) switches to be troublesome. . . . They need thorough cleaning when they are not damaged beyond repair."

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So while I wait for caps and resistors, a couple things.

Geoff, you never have mentioned how they sounded? Did you give em a spin?

I hooked up the one I have yet to open. Before doing so I checked the woofer's response to manually pushing in and releasing and it was fairly quick return. These will be redoped for sure, as well as the mids. Once hooked up and listening to Mama Tried from "Live Dead" I am reminded why I liked these better than the Advents of the day. The tweeter would not give any sound and manipulating the switch had no effect. I had Diane involved in the experimenting and she confirmed no sound using the open bottomed plastic cup method. I am very lucky to have her and her humoring me and actual interest in this stuff.

We listened for a while at various volumes and I am thoroughly encouraged. I use a Marantz 2230 that has been completely refurbished by Pat Font from AK in my work shop for those interested. Source is a cheesy mid 90's Yamaha disc player with no DAC in line. Sound is pretty damn good.

I have also checked the drivers in the cab I have opened and all drivers produce sound! I will guess that the "dead" one is probably OK and will confirm that once I crack that cab.

Hi Geoff,

Looks like you have a great pair of speakers and a very nice project here.

Totally agree with you about the wood screws - - - that type of particleboard is particularly crumbly and certainly would be improved with a better machine screw attachment. Keep up the good work and great posts.

Robert, thanx again for the kind words. We did go to Woodcraft on Thursday and I was disappointed in their offerings for t nuts or similar and ended up going to Fastenal and found appropriate offerings there. I did find an alternate Tung Oil that I will try on something down the road and Diane found what she was looking for. More on that later.

Yes I did have clams while we were on the coast, always a treat!

I have seen the thread on the KLH 28 refurb, wow that is fabulous. Thanx for the tip.

Helpful note from Roy:

"I've found those KLH 5 (and 23) switches to be troublesome. . . . They need thorough cleaning when they are not damaged beyond repair."

Kent et al, I will be sure to dose the switches.

Geoff

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Geoff

From pics it seems that crossover inductors are placed quite closely to mounting plate made most likely from aluminium. Whe I redid Kef Cantatas with similar construction few years ago, considerable improvement in sound quality materialized when aluminium mounting plate was replaced with one made from masonite. I suppose aluminium mounting plate introduced some kind of crostalk between cored inductrors.

Kimmo

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So I received my parts and had time to rework the first board. The replacement resistors were bigger than OEM but still able to fit without any trouble. I dollop a stripe of goop on the backside to affix to the board before soldering. It seemed prudent to inspect all wiring considering so many exposed and crossing wires. I will stuff gaps on board with fiberglass to try to assure no shorting. 

 

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The caps were also larger than OEM but with a little stacking and gooping was able to find a comfortable fit and rewiring was no trouble.

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I also dosed the switches with deoxit a few times, spun the dials many many times to work it in and re-installed the terminal gaskets and retainers and cleaned up the pointers. 

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working out my options for t nuts and that will be next and then we can close these up and fir 'em up! not exactly sure how much time I will give these cabinets for now, likely their sound will dictate how much effort I give them.

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Lookin' good!

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So I have installed the t nuts, drilling new pilots and rotating driver orientation 30 degrees effectively splitting the difference from original screw holes. Not so sure of that math. :unsure:

Dab a little JB Weld on the shoulder

 

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and draw it into place

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I did run into a little snag though. The rotation of the driver position landed a new pilot hole basically at 12:00. When drilling pilot which was something like 5/16" I encountered a staple from the mid box which was a surprise. Didn't know that was in there!

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which has a brace epoxied and stapled to the backside of the baffle. Just my luck to run into that. I chased the staple with a 1/8" bit a few times around it and was able to push it in to reveal the head that was embedded below surface! Also the box was very close to the pilot so I had to buzz off a tab from the shoulder of the t nut so it could be inserted. At least on the second one I will know what to expect.

I re-stuffed the box and re-installed the woofer and fired it up. Sounds real nice and the switches are working properly and nicely. 

I have already cracked the second one and have already started working the board. By the way, the tweeter in this one is fine once the crossover is eliminated.

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Great pics and nice work with the new T-nuts, and yep, 30-degree rotation sounds right to me. While it's nice to bite into fresh "wood", am just wondering if maybe you could have simply enlarged the original screw holes (for the new nuts) and avoided the dimensional clash with that mid box. 

 

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thanx Robert, I thought 30 degrees made sense. As for using original holes, I suppose I could have but for a variety of reasons went into virgin wood. The originals had compromised some of the fall aparticle board from original install, and the lack of pilots created some bulging of the areas. Also I observed during extraction of driver that some of the screws were less than perfectly plum when installed. All these things added up to choosing the 30 degree rotation.

Besides which, I enjoy a challenge.

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Hey Geoff!

You're doing a great job with these and great documentation! You will be quite impressed at how good these sound when you're done. 

The black liner grill cloth was used so you would not be able to see the drivers through the linen fabric, and the cloth shielding  the woofer basket is the same as the Six's and Twenty Threes. I prefer this over the thin tissue type paper used in AR's, which is always shredding and falling apart when I open up a pair.

Looking forward to your listening impressions. If you have a space where you can spread them out, do it and be prepared to stage like sound!

Glenn

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