Advice on taking some 1968 K-Horns apart

[hornsofplenty]

Greetings all, first post here.

 

Two pairs of K-Horns have come into the care of a small group of hifi party aficionados.

 

The oldest of the two pairs, also unmodded since 1968 and cosmetically well worn, is due some renovation. Given the sanding and possible need for the application of new veneers to its wood panels and edges, we expect it will be practical to disassemble the speakers to remove drivers and electronics that might otherwise be subject to vibrations and shocks while the work is taking place.

Do you agree that disassembly is necessary and what advice do you have for successful disassembly and reassembly?

 

In addition, this particular pair of speakers has the top hat fixed to the bass cabinet (*see speaker pics*), with no 'lid'/top face to the bass cabinet were we to separate them (which we'd like to do so as to raise the top hat with a riser middle extension – *see London Loft pic*). 

 

Any advice on separating top hat and bass cabinet and ensuring the bass cabinet with new lid is engineered so that its bass performance isn't compromised?

 

Big thanks in adv!

[DizRotus]

Welcome.

 

I would remove all components to do extensive woodworking to refinish them.   Not trying to be snide, but my suggestion is, if you need detailed disassembly instructions, then don’t do this.  I’m confident you’ll do fine.

 

While inside the bass bins, I would seal the interior joints with RTV silicone and be sure to reattach the woofers with as many screws as possible, rather than the four Klipsch used in Hope.  You might also consider front mounting the horns to the  baffle boards, or at least radius the openings at the front if rear mounted.  If inserting collars between the top hats and bass bins is important to you, these other details might be also.  All of the foregoing didn’t  “make a dime’s bit of difference” to PWK at the production stage, but, IMO, they’re worth the time, effort, and cost at this point.

 

I would replace the K-77 tweeters with Crites 120s and refresh the capacitors in the networks.  I’d also replace the connection terminals with Neutrik Speakon connectors.  Also, replace the gaskets between the squawker horns  and drivers.  Get to know a Bob Crites at critesspeakers.com.  He’s a knowledgeable resource with the utmost integrity.

 

 

Good luck and please  post photos as you progress.  OBTW, “dime” is Yank-speak for a ten penny coin. 

 

 

[hornsofplenty]

I've no working snide detector so it's all gratitude. Thank you!

Would placing a new 'lid' on top of the bass cabinet (given the one that's seen in the pics would remain with the top hat once separated) be straightforward? Just a birch ply piece cut to the same size and screwed into place using existing fixings?

[hornsofplenty]

Also, you'll see we have side wings that would have previously had grill cloth attached. They're structurally unsound towards the bottom of the bass cabinet assembly, so we'd assume these could simply come off with no detriment to the sound? Alternatively we could restore the grill cloth even if the top horn is likely to remain open. Any recommendations here? 

[glens]

Are you sure that the bottom of the top-hat isn't in fact the top of the bass bin and the top-hat doesn't have a bottom?

[hornsofplenty]

Glens, it looks to us like the flat piece is more fully secured to the top-hat (therefore its bottom) that it is to the bass bin. Are you getting at the idea that it could matter less to replace the bottom of the top-hat than mess with the bass cabinet?

[glens]

I don't know.  Were I to build something like that my inclination would be to put a structural top on the bass bin (it's a complicated assembly) and maybe some simple cleats on that to accept the sides of the top-hat, which doesn't need to be anything special structurally.  But like I said, I don't know.  Just asking.

[DizRotus]

On 12/16/2019 at 6:39 PM, glens said:

Are you sure that the bottom of the top-hat isn't in fact the top of the bass bin and the top-hat doesn't have a bottom?

 

That is what I was thinking.  Leave the top of the bass bin intact,  put on a collar (spacer) if you like, then make a new bottom for the top hat.

[kevinmi]

The bass bins will not come apart, except for the trap door for the woofer. Everything else is glued together. The tops are screwed together, so they can be disassembled easily.

[hornsofplenty]

Thanks Kevin & thanks all. I hope it’s the case that the bass cabinet has a lid already out of the current construction. Will get to  check at the weekend.

[hornsofplenty]

Asking this again:

You'll see we have side wings that would have previously had grill cloth attached. They're structurally unsound towards the bottom of the bass cabinet assembly, so we'd assume these could simply come off with no detriment to the sound? Alternatively we could restore the grill cloth even if the top horn is likely to remain open. Any recommendations here? 

 

Thanks in adv!

[Khornukopia]

8 minutes ago, hornsofplenty said:

You'll see we have side wings that would have previously had grill cloth attached. They're structurally unsound towards the bottom of the bass cabinet assembly, so we'd assume these could simply come off with no detriment to the sound?

 

The side grills are decorative, so it is okay to leave those off until you build new frames and new grill cloth. The important thing is to cut a new panel to attach to the top of the bass bin, covering the space between the cabinet and the wall, if you are lifting up the top section on a pedestal.

[hornsofplenty]

Thank you!