KLH Model Five Restoration

[FWBlack]

Hi
I just wanted to say thank you to the information on this site.  I just finished restoring and recapping a pair of KLH Model 5s.  My uncle had given them to me several years ago and they have sat in storage since then, he got them from a house he was cleaning out - I assume the original owner.  A few months ago I moved something and saw them and took a picture of the label and was going to sell them... that is until I searched and found this site and realized what I had!  The drivers were in great shape (needed re-sealing which I did with sealer from vintage-ar on eBay).  I refinished the cabinets with Watco walnut Danish Oil.  I replaced the caps with Dayton Audio audio grade caps and replaced the resistors with Jaztzen Audio Superres and Mills resistors.  I also, after reading about ground issues, ran 14ga wire between all the ground tabs.  I replaced the lead wires from the xovers to the drivers and ditched the wire nuts and soldered the connections.  I also used DeoxIT D5 on the rotary switches.

They sound absolutely amazing!

One thing I came across is that one of the crossovers was wired wrong - one of the caps was connected wrong.  I drew out the connections and was having a time matching it up to the factory schematic provided on this site... so I picked up the other xover and it was wired correctly!  I guess it had been wrong since 1970!

[JKent]

Welcome FWB!

Nice work on those speakers. The Model Five crossovers can be a bit confusing with all those dual capacitors so glad your detective work paid off. Enjoy the music!

Kent

[FWBlack]

Kent - looking at the other recapped images and info, I assumed I was supposed to replace the dual caps with 2 caps.  Seems to work well.

Fred

[JKent]

9 minutes ago, FWBlack said:

Kent - looking at the other recapped images and info, I assumed I was supposed to replace the dual caps with 2 caps.  Seems to work well.

Fred

Absolutely right, although sometimes the 2 sections of a double cap would be wired in parallel. IIRC some crossovers had a dual 8uF wired with both red leads in parallel, making it a 16uF so in that case a single 16uF replacement would be fine. In other spots there were dual 4uF caps where the red leads went to 2 different points, so those had to be replaced with two 4uF caps. Like I said, a bit confusing compared with other crossovers such as the Model Seventeen.

[JKent]

Working on yet another pair of Fives. These have the pcb crossover, which is nice because the wiring is less confusing but less nice because there's not much room for bigger caps and resistors. Have to get creative with mounting (and no Clarity Caps!)

One thing I hadn't seen before: In addition to the crinoline sheet behind the woofer there was also one over the xo. Probably a good idea because of the open rotary switches.

Speaking of those switches--these are particularly cruddy, which probably accounts for the "dead" tweeter (tweeter is actually fine). Hoping some de-ox-it will fix them up.

I'll post photos when the xo's are complete.

 

 

 

Edited April 5, 2023 by JKent
removed photos

[JKent]

So I removed all the resistors and caps. Tested them all and of course the resistors were all well within spec but I replace 5w resistors with 10w because I've seen burned ones in Fives and Twelves.

The caps were also within spec (except one) but the tolerance on capacitors is really pretty high. One 25uF measured 30.2 but that's only about +20% which isn't terrible. Of course modern film caps are virtually spot on.

The one problem was one of the double 4uF caps. Both legs measured 0.0uF and there was a chunk missing. A little hard to see in this pic but on the right side there are 2 leads coming out--it's 2 capacitors in 1 body and both of them are bad. Damn Callins caps! I guess this is why the tweeter didn't work.

[RoyC]

On 12/31/2020 at 7:45 PM, JKent said:

So I removed all the resistors and caps. Tested them all and of course the resistors were all well within spec but I replace 5w resistors with 10w because I've seen burned ones in Fives and Twelves.

The caps were also within spec (except one) but the tolerance on capacitors is really pretty high. One 25uF measured 30.2 but that's technically within spec. Of course modern film caps are virtually spot on.

The one problem was one of the double 4uF caps. Both legs measured 0.0uF and there was a chunk missing. A little hard to see in this pic but on the right side there are 2 leads coming out--it's 2 capacitors in 1 body and both of them are bad. Damn Callins caps! I guess this is why the tweeter didn't work.

In my experience that "double" cap is the most common point of failure in the KLH 5. Corroded switches is another common problem, but they are usually able to be cleaned.

Roy

[JKent]

Got my cap order and finished them up. Those switches Roy mentioned were very cruddy but De-Ox-It and canned air seems to have fixed them up. I used inexpensive mylar caps from Carli and Erse, new 10w basic resistors. All the parts came to about $30. A real bargain! Madisound is closing out Carli caps so I bought a bunch of 15s and used them with my previously-purchased 10uF "surplus" caps from Madisound for the 25s. Sorted through the 15s to find 2 that measured about 15.5uF to replace the 16s. 3 and 4uF caps are Erse PeX.

Speaking of Roy, Using his goo on the Model Five makes a significant improvement. I didn't realize this when I had my own Fives--it was only after I'd sold them. The improvement is NOT subtle. Following Service Bulletin 60 Here: http://www.classicspeakerpages.net/library/klh/other/klh_schematicsservice/klh_service_bulletin_60.pdf  I applied the butyl sealant to the cloth woofer surrounds, dust cap AND the midrange speaker surrounds. The bass is now deep and tight. Really excellent.

You could coat the dustcaps with diluted white glue--they dont need to be flexible, but I was eager to get these done and have a listen. I didn't do anything with the cabinets--the owner will take care of that himself.

Edited January 5, 2021 by JKent

[FWBlack]

Wow - I just realized that I didn't coat the dust caps on the model 5's I rebuilt.. thanks for the reminder!  I had to order another small jar of the stuff from Vintage AR on eBay: https://www.ebay.com/itm/ACOUSTIC-RESEARCH-SPEAKER-CLOTH-SURROUND-WOOFER-SEALANT-KIT-ALSO-KLH/193701935734

[RoyC]

3 hours ago, JKent said:

Got my cap order and finished them up. Those switches Roy mentioned were very cruddy but De-Ox-It and canned air seems to have fixed them up. I used inexpensive mylar caps from Carli and Erse, new 10w basic resistors.

Nice and neat as usual, Kent!

Roy

[Cjj2d]

My Model 5 crossovers are in the middle of a recap job, it was found that the potentiometers have failed and need replacing. Anyone know where to find some?

 

This thread is great and detailed! Once the recap job is complete I will be refinishing the cabinets! They are in pretty good condition, but a little TLC will be nice. Hopefully we can find some potentiometers to replace the broken ones. 

[Scout]

I have a pair of KLH 5's that I haven't used in 30 years. I always loved the sound. (have Harbeth's now)

The tweeter is out in one and the mid in another.

Are they worth repairing?

I have a local speaker repair guy, but he's not sure where to get replacments speakers and parts.

Does anyone know?

Thanks! 

[FWBlack]

On 1/16/2021 at 8:11 AM, Cjj2d said:

My Model 5 crossovers are in the middle of a recap job, it was found that the potentiometers have failed and need replacing. Anyone know where to find some?

 

This thread is great and detailed! Once the recap job is complete I will be refinishing the cabinets! They are in pretty good condition, but a little TLC will be nice. Hopefully we can find some potentiometers to replace the broken ones. 

Do you mean the switches?  There are on potentiometers.  I don't know where you'd get those.  Try cleaning them up with this stuff: https://www.amazon.com/gp/product/B00006LVEU

[FWBlack]

42 minutes ago, Scout said:

I have a pair of KLH 5's that I haven't used in 30 years. I always loved the sound. (have Harbeth's now)

The tweeter is out in one and the mid in another.

Are they worth repairing?

I have a local speaker repair guy, but he's not sure where to get replacments speakers and parts.

Does anyone know?

Thanks! 

Have you tested them directly and not through the crossover?  A bad crossover component or rotary switch could make it seem like they're bad when the drivers are actually good.  The crossovers probably need rebuilding anyway.

[FWBlack]

44 minutes ago, Scout said:

I have a pair of KLH 5's that I haven't used in 30 years. I always loved the sound. (have Harbeth's now)

The tweeter is out in one and the mid in another.

Are they worth repairing?

I have a local speaker repair guy, but he's not sure where to get replacments speakers and parts.

Does anyone know?

Thanks! 

Oh, and yes, they're worth repairing.   See my post about about rebuilding my crossover and refinishing my cabinets.

[JKent]

Coincidentally, while you were posting here I was posting a new Model Five thread: 

 

[Scout]

42 minutes ago, FWBlack said:

Have you tested them directly and not through the crossover?  A bad crossover component or rotary switch could make it seem like they're bad when the drivers are actually good.  The crossovers probably need rebuilding anyway.

No I haven't. I'm trying to find someone who will repaid them for me. I'm in Pittsburgh, PA

 

[Scout]

Does anyone know someone in Pittsburgh PA who would repair my KLH 5s?

 

[JKent]

If you mail me the crossovers I can rebuild them. Send a PM if interested.

[Brad1234]

I just finished a restoration on some Model 5's and think they turned out pretty incredible and wanted to share my photos. I have 2 questions for the forum, 1) what do u think a fully restored set like this is worth and 2) is there anything I should do about the grill cover staining?  
 

The grills appear original but are in great shape other than the discoloration where driver openings are. Is this a "vintage" characteristic ok to leave alone or should i remove and wash them, or replace them?  I havn't found this shade of brown linen (or polyester fake linen) for sale anywhere. 

[JKent]

Nice work!

One member here (sorry, I forgot who) had good success with Blue Coral DC22 Upholstery Cleaner Dri-Clean Plus. Those KLH grilles can be tricky because of the layer of black scrim behind the cloth. I don't know if it might bleed through if you spray the top fabric. Might be worth a try. I'd vacuum the grilles first.

[Brad1234]

Thanks Jkent!  I found some vintage-looking advent/AR/KLH fabric at Midwest Speaker Repair online for $20. They have a beige-ish brown and an off white. I have used the off white on my Advents and it came out fantastic!  Do the grills really need the black scrim behind the grill cloth?  I did try vacuuming the grills and it helped a little. If i should reuse the scrim cloth I will be sure to hand wash it before reinstalling to try to keep it from bleeding on to the new fabric. 
   Also, any advice on where to get an electric stapler to use the tiny 1/4" staples to install the fabric?  Gluing them is a pain. 

[RoyC]

39 minutes ago, Brad1234 said:

Thanks Jkent!  I found some vintage-looking advent/AR/KLH fabric at Midwest Speaker Repair online for $20. They have a beige-ish brown and an off white. I have used the off white on my Advents and it came out fantastic!  Do the grills really need the black scrim behind the grill cloth?  I did try vacuuming the grills and it helped a little. If i should reuse the scrim cloth I will be sure to hand wash it before reinstalling to try to keep it from bleeding on to the new fabric. 
   Also, any advice on where to get an electric stapler to use the tiny 1/4" staples to install the fabric?  Gluing them is a pain. 

Nice cabinet work!

The black cloth is not necessary if you don't mind seeing the grill frame or underlying cabinet baffle and drivers. AR accomplished this by painting the baffle and grill frame black.

Electric staplers and staples are sold by all hardware stores. The KLH grill frame is thin, and it is possible for 1/4" staples to protrude on the visible side. I glue 1/16" wood strips to the inside edge of the frame to prevent this.

Roy

[JKent]

I agree completely with Roy but would add a couple of thoughts:

1. Since you know where to get new cloth, why not give cleaning a shot?
2. Gluing thin wood strips works well but one member (again, I forget who it was) said he took his strips of 1/4" staples and using some scissors cut a little off the legs. I haven't tried this myself but it sounds like a solution.

btw, for thin frames like those on the KLH, you don't really "need" an electric staple gun. An Arrow T-50 works fine. I have both, and on some old frames even the electric needs to be really pushed down on hard.

Kent

[Brad1234]

Thanks Roy and Kent!  I guess you are right I could try removing the original cloth and hand cleaning it real well to see if it cleans off?  I could save the grill cloth for another project if it works. I dont understand why the KLH cloth stained over time just where the driver openings are cut in the masonite backing?  I think I will just go with gluing the new ones on since staples might puncture thru masonite.  I use the gorilla glue fabric glue on my advents, it sticks well and works fairly quickly but its just messy and time consuming gluing and weighing it down to keep it stretched tight from side to side.