KLH Model Five Restoration

[fallen_trumpet]

I am new to this forum, but thought some others might be interested.

A friend from my home town of about 2,000 people was about to discard (into the trash) a pair of KLH Model Five speakers.  I learned of this just in time to save these from the landfill. 

As far as I can tell, there was one owner of these until she died in 2003.  Since then, these have been in a storage 'shed'... and moved around with a furniture dolly/hand truck... so there is some wood damage

I just got these home and have not had time to open these (or see how they sound, yet)... but I plan to rebuild the crossovers (or possibly send to JKent), reseal the surround (using sealant from RoyC) and refinish the wood cabinets.

I will only work on these occasionally as time allows, but will post occasional updates as I make progress.

Oh... serial numbers are 022339 and 022342 (only 3 digits apart).

Regards,
Fred

[Norman Nicolai]

Welcome to the Forum!

I wish I had that kind of luck finding classic speakers in the trash...

Sounds like you are on the right track, following the tried and true formula for proper KLH speaker restoration: 

Replace the capacitors in the crossover, never use anything other than the RoyC dope on the surrounds, and gently refinish the walnut cabinets. From the photos you have supplied, it looks like the cabinets are in good shape. I hope the drivers are in as good a shape, although you don't show any photos of those.

For cabinet refinishing I've used thinned tung oil on a set of Model 17's, Minwax Restore-a-Finish on a set of 22A's, and Watco's Walnut Danish Oil finish on a set of Model 6's. I like the finish I got on the 22A's and 6's the best. YMMV.

I look forward to seeing photos of your progress. Don't hesitate to use the Forum if you need any future advice. It's never steered me wrong.

[fallen_trumpet]

Hi, Norman.

Thank you for the guidance.

I am thankful for this forum and it's members, having already learned a lot by reading other posts and trading a few emails with JKent and RoyC to get me pointed in the right direction. 

More photos to follow shortly. 

Fred

[JKent]

Good advice from fellow NJ guy Norman but I don't think those refinishing options will work on these speakers. The Model Five and their little brothers the Thirty-Threes (maybe some others) had a hard finish--maybe varnish? It is impervious to lacquer thinner. I ended up using a citrus-based stripper and after they were thoroughly stripped I used Watco Danish Oil. Really brought out the beauty of wood that had been hidden by dull, orange varnish.

I've seen other photos of Fred's cabinets and there are some unfortunate scratches from the handtruck. I'd suggest stripping the cabinets with citrus- or soy-based stripper and very gently hand-sanding those scratched areas. Any dents or deep scratches can probably be steamed out.

Great speakers at a great price.

[fallen_trumpet]

Hi, John.

The price was definitely right!  ;^)

Here are more photos of the worst of the Model Five cabinet damages.  (I'll probably get around to listening and opening these to look inside tonight or this weekend.)

Fred

[fallen_trumpet]

KLH rookie question...

I believe I read somewhere that the KLH Model Five grill is held in place by velcro, but what is the best way to 'grab' the frame to remove it?  (I don't want to insert anything into the 'slot' between the frame and wood that might damage either or both.)

[fallen_trumpet]

Ahh... i see now that the black border is not part of the removable grill.... and I see the woofer is screwed in (not glued), so must be from a somewhat later manufacturing year.  (I believe early years, the woofer was glued to the cabinet.)

Fred

[fallen_trumpet]

Just additional observations... grill fabrics appear to be in good shape... likely just need to clean and re-stretch (especially the black)?

And the KLH logo is 'screwed' (not glued), but one is missing... so I'll search through the forum for guidance regarding replacement logo emblems.

Fred

[b_sdaddy]

Nice find! I bagged a pair for €50/$50 a couple of weeks ago.

Ordered new caps, and already sanded down the cabinets, re-oiled, and re-clothed the grilles with linen.

Bass is great, so holding off with the "goo" for now. Might be price-prohibitive, getting it to Belgium from the U.S.

Can't wait to hear the difference when the new caps are fitted. 

If you're half as happy as me, with them, then you're one happy bunny!

[fallen_trumpet]

Looks very nice...hopefully I can do the same for mine.

[fallen_trumpet]

I finally found a little time today to start looking more closely at the restoration of my newly acquired KLH Model Fives..  Here are a few photos and misc. observations/comments after opening both cabinets thus far.

But, before opening each cabinet, I played a little music... I heard sound from the woofer and mid range drivers, but nothing from the tweeter (as expected for ~50 year-old Model Fives that have probably never had the cabinet opened since they were purchased).  But with components out of the cabinet, I was happy to confirm all drivers produce sound so look forward to the listening after the crossover has been rebuilt and woofer/mid driver surrounds have been sealed.

Date code stamped on both tweeters is Feb 3, 1969 and mid range drivers are date stamped March 19-20, 1969.  There appeared to be a date stamped on one woofer, but it was not readable.  From these date codes, I assume these Model Fives were built/assembled perhaps mid-to late 1969 (assuming 3-9 months after manufacture of the components).

Interesting that there is a 1/4" gap between mid range drivers in one cabinet, but metal frame of the drivers slightly overlap in the second cabinet.  Just a sign of cabinets holes being cut by hand instead of a more tightly controlled manufacturing tolerance, I suppose.  Perhaps not audible - just an observation.

Behind the woofer is a thin sheet of a woven fabric (is it linen?) and behind that pink 'insulation'.  I suppose the fabric is intended to help keep the 'insulation' from getting into the woofer.

The cavity of the woofer is open to the tweeter and the same insulation fills the space behind the tweeter.

The mid range cavity is sealed and is filled with a higher density 'insulation' of some sort.  (I assume there was an acoustic difference that led KLH to use a different material in the mid driver cavity?)

Tweeter, mid range drivers and woofer are all screwed directly to the particle-board type wood (no metal fasteners).  I suppose if one only opens the cabinets every 51 years or so, this should not be an issue, but others that have restored these KLH speakers, have you added metal fasteners of some sort when re-assembling?

I was a little surprised speaker wires are soldered to the woofer and then connected back to the crossover using wire nuts.  (I suppose I expected some sort of slip on connector on the woofer like KLH used on the mid-range drivers.

I've also added a photo of the point-to-point wired crossover, although I've not yet removed it from the cabinet (and haven't yet decided whether to replace the components myself or let expert JKent rebuild the crossovers for me).  I certainly will seal the woofer and mid drivers with the sealant from RoyC as part of this restoration.

I'll stop there for tonight.  Any thoughts, comments, suggestions/recommendations are certainly welcome.

I've purchased Franmar soy based wood stripper (formerly Soy Gel, now called "Blue Bear") to start stripping the old finish from the cabinets, after reading of good results from JKent and others, and hope to start that soon.  (I'll test the bottom of one cabinet first, before proceeding to the full cabinets.)

Edited March 15, 2020 by fallen_trumpet
Updated comments for 2nd cabinet

[fallen_trumpet]

Seeing cabinet restoration guidance...

Removed the crossovers this weekend and looking at the cabinets and seeing a lot more veneer damage now upon closer inspection.  Any guidance regarding the cabinets? 

Repair first, then strip and refinish?

Strip first, then repair and refinish?

Continue efforts to patch and repair old veneer or too far gone? 

(Maybe my inexperience in wood working has scared me into thinking it may be best to just repair the cabinets and add new veneer, or is that a really bad idea?)

Also... looking ahead a bit too far perhaps, but what is the best putty/caulk to use when replacing the old 'putty' and re-installing the drivers?

[JKent]

In reverse order;

You can get "duct seal" cheap in a home improvement store. It come in a brick and you pull off a piece, knead it and roll it into a thin worm. Put that around the perimeter of the hole. It's sort of like working with children's plasticene modeling clay.

Better--get foam gasket from Parts Express. It seals well and makes it easy to remove the drivers in the future.

The cabinets: Glenn is really the master here but a couple of tips:

• On those open corner seams, see if they can be pulled together with big clamps. If not, if the particle board has swollen, you need to dig it out before using glue and clamps. I have tried just brute force and it doesn't work. Dig it out.
• For the corner bashes, Glenn would carefully cut pieces of scrap veneer and fit it in place like a jigsaw puzzle so the patch disappears. I use JB Wood Weld epoxy, tinted with Mixol #22 dye and just fill in, file/sand when cured and hope no one notices. You can also use Mohawk stick epoxy--it comes in walnut and you just cut off a piece, knead it thoroughly and press in place, forming to the proper shape (but it will have to be filed/sanded too). Gene goes one step further" He uses a slightly lighter color epoxy and after it's all shaped and sanded he draws the grain on with darker Mohawk pens made for that purpose.

Don't worry. We've seen much worse here.

Kent

[fallen_trumpet]

Good ideas.. thanks.. I will try some ideas Saturday.. 

[fallen_trumpet]

After a bit of experimentation on a single 'panel' (bottom of one speaker), I believe I'm on the right track and am slowly building confidence working with veneer.

I was able to first use an Xacto knife to dig a slight amount of substrate from under separated veneer along one edge  and then glue and clamp with pretty good result. (Sorry for the blurry photo showing clamping.)  I still need to sand and stain to make the newly glued seam less noticeable.

I also tried Blue Bear soy based wood stripper (Paint & Urethane Stripper).... Franmar customer service told me this is the exact same as their "Soy Gel marketed as 600GL" but in a different package.  I'm still not 100% certain how this product, their 600GL and their 605PRO products vary, when one is preferred over the other, etc.

This was slow acting but I covered the surface with plastic wrap to keep it moist and let it work an hour or two before removing. 

I still need to sand and fill gouges and gaps, but I think I will proceed and do the same to both cabinets today.

Photo of "before" working on the bottom panel of this speaker.

Then other photos of the same bottom panel during and after stripping (but still prior to filling gouges, sanding, refinishing...).

Thanks again for the guidance.  More to follow after I spend a few nights on the wood, as well as the drivers and crossovers.

Fred

[JKent]

Coming along nicely!

One suggestion for future glue/clamp jobs: Put wax paper between the wood block and the cabinet to prevent accidentally gluing the block to the speaker.

[fallen_trumpet]

Thanks for the reminder!

Yes, I've seen other videos that show using wax paper to help ensure wood blocks aren't accidentally glued to the surface being repaired... so in hindsight, I should have used wax paper, which will also allow me to place my wood blocks more directly on the seam edges instead of slightly away from the seam edge.  I will do that for the next seam repairs! 

Fred

[ra.ra]

1 hour ago, fallen_trumpet said:

I also tried Blue Bear soy based wood stripper (Paint & Urethane Stripper)....

I am unfamiliar with these stripper products, but it appears your early attempts are rather successful. There still seems to be no consensus about the precise type of wood finish originally used on the KLH Five, but I have read about agonizing attempts to strip these cabinets using other products. Perhaps your thread will open new doors for future restorers of this excellent speaker model. Please keep us informed.

[fallen_trumpet]

After a bit more experimentation, it seems to me that 15-30 minutes of soak time with this soy gel stripper is just as effective as an hour or two, removing most of the old finish that comes off like 'sludge', as shown.

Here's one cabinet stripped and drying and a bit of cleaning with mineral spirits...

and then mostly dry (cabinet on the left), and probably ready for sanding and filling gaps (next to 2nd cabinet on the right that I haven't started stripping, yet).  (Difference is more noticeable to me in person than in these photos.)

Fred

[JKent]

Beautiful! The stripping really brings out the beauty of the walnut.

[fallen_trumpet]

Thanks, JKent.

If it looks good to an expert like you, then I must be on the right track! 

Thanks again for your ongoing guidance!

Fred

[b_sdaddy]

Watching closely.

I was lucky enough to find a pair that were in excellent condition. A very light sanding down, and then oiled, with new linen grille cloths, and they're cosmetically as good as I need them to be.

Interested in your next step, with regards to the crossover. I do all of my own work and have calculated €50/$50 for new capacitors. Would you see this as OK, or would you spend more? I have no idea as to the return on your investment when it comes to caps.?

I must say, I'm holding off on the 'goo' for now: I have too turn my two subs OFF, when I hook up the 5's. With everything else I have, they to 'add' to the overall effect.

The bass is that good. Could it be better?  I'll re-cap first and then consider my options.

 

Rgds

Stephen

[JKent]

3 minutes ago, b_sdaddy said:

I do all of my own work and have calculated €50/$50 for new capacitors. Would you see this as OK, or would you spend more?

The original caps are non-polarized electrolytics. If you use new NPEs that will be the lowest cost option, is true to the original design and should last 20-30 years. Film caps last virtually forever. Mylar is the lowest cost and also has ESR closer to the original NPEs. For each speaker you will need

• one 3uF
• three 4uF
• one 16uF
• one 25uF

Small value film caps are pretty cheap so you could use a combination: Film for the 3, 4 and maybe the 16 (the 16 is for the mids) and NPE for the 25 and maybe the 16.

[fallen_trumpet]

Hi, Stephen.

I haven't addressed my crossovers yet (but need to start thinking about them soon).  But JKent is the expert there, and I'll follow his guidance.

I did order the sealant yesterday... RoyC was sold out so I ordered from "Vintage AR" on ebay... total with shipping to me in Texas ~ $35 for enough to do drivers in both cabinets.

The wood working has taken a bit longer than I expected, partly because of my inexperience working with veneers (and trying to proceed cautiously so hopefully I won't mess things up too much...) and partly because of house arrest (aka, self imposed home lock down because of the virus, so moving more slowly instead of just running to the local hardware or wood working store each time I need something). 

I think I'm going to order some "Mohawk Stick Epoxy - Walnut colored' and give that a try to repair edges and corners of my cabinets that need a bit of attention.  For surface scratches and gouges, I'll probably try the same initially and see how it looks, but wax sticks might be as good or better (and simpler) for certain scratches.  Looks fairly inexpensive from Amazon.com with delivery in about a week.

Fred

[JKent]

Thanks Fred

For the record, just completed another pair of Five crossovers. I used Erse PeX caps and Erse resistors. Total cost of parts was under $35.

I know some respected members here think new resistors are unnecessary but my rationale is:

1. I have seen burned 5w resistors in KLH Model Five and Twelve speakers.
2. Most speakers use 10w resistors.
3. Resistors are dirt cheap (under 0.50 each).
4. Cheap insurance!

Kent