JBL C40 Harkness Looking for Info and a Match

[Johnny_Law]

Finally made some time to pull the back off, unroll the grille, and snap some pictures to hopefully find some clues. Anyone's sharp eye catch anything tell tale?

[srm51555]

Anyone's sharp eye catch anything tell tale?

Looks to be a very nice McIntosh mr67 tuner in the backround.

[Johnny_Law]

Looks to be a very nice McIntosh mr67 tuner in the backround.

Very sharp eye! It's a semi-dead and cosmetically challenged MR71 I'm trying to breathe life back into, along with a dead C24 and MC502, to go in a nice Barzilay stereo cabinet which came from the same wonderful people as this C40.



Maybe it'd be more of a challenge to identify the car.

[Johnny_Law]

The good news is that I've acquired another 030 load (075, D130, and N26) and another 'blonde' C40 cabinet!

The bad news it that the cabinet needs some work - among other things, it needs veneer work. It'll also need the corners fixed as well as multiple dents, and one side re-glued. (Thank you Greyhound shipping!)

Does anyone know the best veneer to use that will match the original 'blonde' C40 Harkness?

And how are they held together? I'll likely need to re-glue one side.

Thanks!

[Wagner]

Does anyone know the best veneer to use that will match the original 'blonde' C40 Harkness?

Birch or Maple, I've had them in both, finished off with a good quality nitrocellulose (if you want an original finish). Maple will probably be easier to find with some interesting figuring but either will present well.

Nitrocellulose will give Birch or Maple that "golden" tone, any of the water based clear coats (like a water based polyurethane) will dry leaving the wood exactly the same color as when you start (as in sanded and dry) so, if you go that route make certain you can live with the hue as is. The degree of change with an oil based polyurethane or similar is something you won't know until you apply it and will generally have more of a darkening effect than lacquer.

If you do want to go with an oil based clear finish I would definitely suggest you go with the "test in an inconspicuous area" first before you do your whole box. The degree of darkening from sample to sample can also be much more inconsistent with an oil based finish due to slower drying time and the way in which the wood takes the finish.

I prefer lacquer as it is more predictable and much much easier to repair or touch up later on if need be.
The degree of "toning" or darkening will also be more consistent from box to box, sans tinting, see below.
In other words, it's easier to get two different boxes to match.

Everyone has seen the pairs of JBLs that exhibit dramatic differences in appearance despite close numbers.
Not a bad thing if they are fairly similar in "color", but I have seen some that I wouldn't want to look at for long as the difference was so apparent.
But that is just the nature of an oil finish, it is capable of not only "enhancing" but exaggerating as well. Two boxes that appear virtually identical raw and dry can quickly turn to looking entirely different after an application of an oil finish-sometimes good, sometimes not so much.

The only totally consistent and predictable solution is book matched pairs, or if you are doing your own veneer work then you can grain match yourself (all of these observations with regards to using OIL based finishes on bare wood).

This also applies primarily to the large real estate "C" type boxes with the "blonde" or lighter finishes; with the well known and loved dark Walnut JBLs of the '70s era you basically get what you get and oil IS the authentic finish obviously, matching issues and all.

One thing I do know from experience is that on FACTORY built boxes with "blonde" finishes, the consistency between example to example and even YEAR BUILT to year built being 5 or more is amazing, so JBL (or whoever the contractor was) definitely used tinting for consistency. That option is available to you as well, but then that's a whole other story!
Still, after stripping them down to clean wood (boxes built years apart) the matches I have had have all been remarkably good, including grain and figuring; this would indicate to me that someone had quite the stockpile of high quality veneer/lumber and sourced it at roughly the same time (I can just see the piles of the stuff, SO BEAUTIFUL)

Lacquer also DOES NOT require any sanding or prep work between coats (if sprayed well) unless you are going for a high gloss piano type finish

Take a photo of how the grille cloth is tensioned and I can tell you if it's a factory build or not (need to see the hardware, should be two studs with wing nuts and washers, also show me how it is all attached); you cannot rely on front and back plate cuts as they were often changed by the end users to accommodate whatever loads they had (weren't always factory boards as most folks saw there was no point in ordering a "kit" from JBL when all it was was the board(s) and "blocks" you needed to facilitate the different driver sizes and to plug unneeded holes)

Unless someone was lucky enough to live close by to a JBL dealer who had all of that material "in stock" they were frequently fabricated with the results being owner skill dependent. Not all of the dealers did glorious quality work either as far as that goes

Another clue is how is the support bracket for a 175DLH treated? The factory structure will be in place even if you do not have or use a "001" load and I have seen few homemades that went the distance doing it as designed by JBL (short of Hal Cox quality boxes). On a factory build, the circular cutout to accommodate and support the "175" will be lined with a heavy felt ring.

Thomas

[Johnny_Law]

Well I moved those pictures to another album and I can't edit that post, so here they are again, or at least the most cringe-worthy:







So silly me, I decided to cut my losses and buy ANOTHER C40 cabinet that was guaranteed to be in good shape. Of course, not only does this one show up the wrong finish, but also has been damaged in shipping on all corners, albeit not quite as bad.

Here are two of the corners:





Greyhound denied coverage of my claim on the first because insurance "doesn't covered finished wood products", and the seller of the second has gone AWOL.

So here I am, now I have 1 complete blonde C40, 1 complete extra 030 load, 1 damaged blonde C40 cabinet and 1 damaged walnut C40 cabinet. Time to learn how to repair cabinet wood and how to lay down veneer.

In the meantime I've been busy scratching the JBL itch and have acquired a few other pairs of speakers ... and tonight will be picking up a 6260 amp.

[audiomagnate]

I'm cringing, but that looks repairable if you want to put the effort into it. Pipe clamps, wood glue, Durham's Rock Hard Water Putty and a lot of elbow grease might be enough to get them ready for some fresh veneer.

[Johnny_Law]

Thanks, yes that's what I imagine it'll take, but the 'bones' of these cabs are still good, I think, so hopefully I can succeed in the repair. Plus, at this point I'm out of a sizeable chunk of change and would rather make lemonade from lemons than let the $ burn and keep searching. Not to mention that I'm getting impatient and want to get a Harkness pair up and running!

[Johnny_Law]

I'm finally tackling this project, and I've made a sister thread over on AudioKarma. https://audiokarma.org/forums/index....#post-14148566 I can edit my posts there, so I don't lose pictures like has happened here.

At this point I've got both cabinets down to the bare wood, ready for re-finish. Wager (Thomas) had great advice about nitro lacquer earlier in the thread, and I wish he was still around to follow up about the process. I've never done this before. Do I start with some kind of blonde stain, and then spray the lacquer? Or do I find a blonde-tinted lacquer and just apply that?

Would love any and all advice about what products to use and how to apply, to achieve as close to an original blonde finish as possible. Thanks in advance.

[bedrock602]

I'm finally tackling this project, and I've made a sister thread over on AudioKarma. https://audiokarma.org/forums/index....#post-14148566 I can edit my posts there, so I don't lose pictures like has happened here.

At this point I've got both cabinets down to the bare wood, ready for re-finish. Wager (Thomas) had great advice about nitro lacquer earlier in the thread, and I wish he was still around to follow up about the process. I've never done this before. Do I start with some kind of blonde stain, and then spray the lacquer? Or do I find a blonde-tinted lacquer and just apply that?

Would love any and all advice about what products to use and how to apply, to achieve as close to an original blonde finish as possible. Thanks in advance.

I'm glad you stuck with your project. Can you post a couple of photos here as well, not the entire process, just showing the whole cabinets, front and back?

[Johnny_Law]

I'm glad you stuck with your project. Can you post a couple of photos here as well, not the entire process, just showing the whole cabinets, front and back?

Absolutely - when done? I actually ended up burning through a spot of veneer on the top of one, so I had to strip it off and will be laying down the new mahogany and bleaching it to match (just like the side). Once that's done, they will finally be ready for the blonde treatment.