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Opinions on KLH Model 5

Search for KLH Service Bulletin #60. It talks about material and where to apply it. That comes from the horses mouth (KLH). Here's a snippet.

Note that less is more as you don't want to overapply and stiffen the surround. That can be as detrimental as not sealing the woofer. Thin coat and check for seal with the push test. Look for alternate air leaks too before applying more.

KLH SB 60.png
 
ra.ra said:
Nope, the dope goes on the cap itself - - sometimes it gets slopped over onto the cone a little bit.
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Ah ha! Thanks- I thought they were paper caps not cloth. Will have to take a closer look. I saw a bit of old dope on the paper cone around the caps and have scratched my head a few times on how doping there would do anything.
 
Well got the KLH 5’s. One woofer has a deteriorating voice coil cylinder, both crossovers are ok, with the exception of these 3 terminal polarized common cathode capacitors that are 4uf. They lost all their capacitance according to my tester. That pretty much made the tweeters inaudible. Anyways, replacing those with film.

For the woofer, I had to unbolt the magnet to get the loose pieces out from the back. Then reinstall the magnet (pain in the ass). Bolt it in, but not torque it down. Then remove the dust cap to see the alignment of the pole piece. It’s a matter of whapping the magnet in the right direction with a mallet until the pole piece is exactly aligned with the coil. After that, glue it all in and torque down the bolts. After the surround sealer comes in later this week, I’ll be able to get these things running! :)
 
At one time (1967-70) I had KLH Sixes, powered with first a Scott LK-72 then in 1968 a Heath AR-15, pretty good I thought for a first real system. Then I went to the 1968 NYC HiFi Show and heard Sixes as compared to Fives. I recall a few things about that.

Fives had lots more detail than the Sixes (some music was obviously just missing). Bass was a bit better/stronger than the Sixes. I liked the Sixes mid-range balance better.
 
Robbie_uC said:
Well got the KLH 5’s. One woofer has a deteriorating voice coil cylinder. For the woofer, I had to unbolt the magnet to get the loose pieces out from the back. Then reinstall the magnet (pain in the ass). Bolt it in, but not torque it down. Then remove the dust cap to see the alignment of the pole piece. It’s a matter of whapping the magnet in the right direction with a mallet until the pole piece is exactly aligned with the coil. After that, glue it all in and torque down the bolts. After the surround sealer comes in later this week, I’ll be able to get these things running! :)
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That sounds like a big job. Where did you get a new voice coil?
 
I reused the same voice coil. Had to remove the bits of the aluminum coil former that were coming apart. I think when the woofer was originally aligned, it was ever so slightly offset, so at one point the edge of the aluminum cylinder must of snagged against the pole piece and messed it all up. We'll see how it all holds together, but I'm going to start looking for a replacement model 5 woofer with the round, bolt-on magnet. Unless you know of anyone that makes an OEM style re-cone kit for this? I'd be really surprised if that actually existed...
 
Tim D said:
Search for KLH Service Bulletin #60. It talks about material and where to apply it. That comes from the horses mouth (KLH). Here's a snippet.

Note that less is more as you don't want to overapply and stiffen the surround. That can be as detrimental as not sealing the woofer. Thin coat and check for seal with the push test. Look for alternate air leaks too before applying more.

View attachment 1564192
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Don't overlook the cork used to block the wiring pass thru between the main cabinet and the midrange enclosure. These often fall out or shrink, allowing back pressure on the mids and less than optimal performance of the subs.
 
Robbie_uC said:
I reused the same voice coil. Had to remove the bits of the aluminum coil former that were coming apart. I think when the woofer was originally aligned, it was ever so slightly offset, so at one point the edge of the aluminum cylinder must of snagged against the pole piece and messed it all up. We'll see how it all holds together, but I'm going to start looking for a replacement model 5 woofer with the round, bolt-on magnet. Unless you know of anyone that makes an OEM style re-cone kit for this? I'd be really surprised if that actually existed...
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I think you will find a woofer at a lower cost than a recone kit (and a heck of a lot less work!).
 
spark1 said:
Don't overlook the cork used to block the wiring pass thru between the main cabinet and the midrange enclosure. These often fall out or shrink, allowing back pressure on the mids and less than optimal performance of the subs.
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These don't have the cork - they use mortite(they switched to cork later?). Same stuff used to seal in the woofers. I have a real rubbery, black glue that sticks well to wood. I used it on the wires to seal them in.
 
Robbie_uC said:
I reused the same voice coil. Had to remove the bits of the aluminum coil former that were coming apart. I think when the woofer was originally aligned, it was ever so slightly offset, so at one point the edge of the aluminum cylinder must of snagged against the pole piece and messed it all up. We'll see how it all holds together, but I'm going to start looking for a replacement model 5 woofer with the round, bolt-on magnet. Unless you know of anyone that makes an OEM style re-cone kit for this? I'd be really surprised if that actually existed...
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Did you take any pics? Would love to see the damage and your repair.
Correct original woofers show up on fleabay all the time if necessary.
 
Unfortunately, it was around midnight when I was doing this, and I wasn't thinking about taking pictures at the moment. Apologies
 
How would sealing the midrange surrounds improve their sound, or the sound of the overall speaker? Makes no sense to me.
 
They have the same cloth surrounds as the woofers and are mounted in their own box within the cabinet. I'd guess the thought is that they need the same spring that the woofers do. Just my swag.
 
spark1 said:
The acoustic suspension effect is focused on lower frequencies.
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Well then, maybe it's to keep them supple/conditioned and prevent them deteriorating. Whatever the case, KLH recommends it and I'll do everything I can to keep these iconic speakers in top shape.
 
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