KLH Model 12

[Stephen]

I am brand new to these forums but have fairly extensive experience with restoring and refurbishing vintage speakers. I have recently found a gentlemen with A pair of KLH Model 12 who needs some help. If any one can help with a schematic/wiring diagram that would be wonderful. He is missing the 'contour boxes'. I feel the controls should be incorporated into the speakers themselves or mounted on the back of the cabinets. Did Mr. Kloss use simple pots that could and should be replaced with variable L-Pads?

[JKent]

I am brand new to these forums but have fairly extensive experience with restoring and refurbishing vintage speakers. I have recently found a gentlemen with A pair of KLH Model 12 who needs some help. If any one can help with a schematic/wiring diagram that would be wonderful. He is missing the 'contour boxes'. I feel the controls should be incorporated into the speakers themselves or mounted on the back of the cabinets. Did Mr. Kloss use simple pots that could and should be replaced with variable L-Pads?

Hi Stephen

The Twelves CANNOT be played without the contour boxes--they are the crossovers. And those aren't simple pots--they are complex and unobtainable rotary switches.

Here is the Manual:

http://www.classicspeakerpages.net/library...nstructions.pdf

I have seen unscrupulous or ignorant ebay sellers offering Twelves without the boxes--they are useless that way.

Here is a thread that shows some contour boxes I recapped:

http://www.classicspeakerpages.net/IP.Boar...amp;#entry72101

and here's another that shows a whole pile of crossover boxes:

http://www.classicspeakerpages.net/IP.Boar...amp;#entry73728

Post #34 gives a blow-by-blow description of the rebuild. One photo there also shows the innerds of the rotary switches.

The best way to get the Twelves up and running is to buy a pair of contour boxes. Maybe put an ad in the For Sale/Wanted section of this forum. I know Rob has at least 3 pair of boxes. maybe he wants to sell a pair

Another possibility: Try to build a Model Five crossover (or buy them). The Model Five used exactly the same drivers as the Twelve, in a smaller box. The crossover is much simpler than the contour boxes and there are schematics in the Library here:

http://www.classicspeakerpages.net/library...ematicsservice/

Good luck

Kent

[Stephen]

Thank You so much, I was having a hard time understanding how a speaker with xover points of 800 Hz and 4KHz could have four frequency bands of attenuation; the Mids must be wired parallel and band passed to sperate F ranges?

Knowing the entire XO is in the Conutor box is particularly hepful. Kent, your model 5 approch seems most expediant. I'm not too wild about justifing the exra resistance of the wire lenth. For as few times as one needs to attenuate individual drivers why not fix the box onto the back of the cabinet? And, for that matter why would a woofer even need attuation!?

I will be a day or so reviewing your links and resources, Thanks again, this is fantastic.

Stephen

[JKent]

Glad to help. Originally the Twelves came with TWO sets of cables; a long set, so you could sit in your listening position and adjust the levels (this was before wireless remote control ). The short set allowed you to stick the box on the back of the speaker, out of sight. There is velcro on the box and on the speaker.

Here's how it is described in the manual:

If you want to place the control box out of sight on the rear of

the speaker cabinet after making initial adjustments with it,

the short cable will avoid an excess of wire behind the cabinet.

The long (40-foot) cable is for permanent or temporary use of the

control box in a remote position.

btw--these are really nice speakers!

Kent

[Stephen]

I think so too, that woofer must have at lest 1.5 cf of volume to operate in. And how thick is the walnut veener?

Digesting,

Stephen

[JKent]

Don't know exactly. The veneer is much thicker than most "modern" veneer so you "can" sand it but VERY carefully--especially at edges and corners. If you don't have to sand try using Howard's Restor-a-Finish. It works very well. Or try this:

http://antiquerestorers.com/Articles/SAL/smothoil.htm

Kent

[Stephen]

Great stuff, again. And you are so right about the edges and corners. I have mostly done AR speakers with Advent and KLH a close second in refinishing jobs. Just prior to staining a properly sanded piece I rinse it with a 4 to 1 mixture of water and chlorine. As soon as the surface is dry to the touch the stain is applied; the water/chlorine wash opens up the wood cells and the stain is soaked up. Next I like to rub in several coats of Tung oil, the more coats the glossier or glass like the finish.

[JKent]

Thanks for that bleach tip. It doesn't lighten the wood? I like Tung oil for my radios (they were originally lacquered) but for speakers most folks here like Watco Oil. The originals were oiled and not glossy. btw--do you know about johnnieo's epoxy & Mixol filler for corner bashes?

Kent

[Stephen]

I have for the most part used that mixture on a sanded and just about ready for staining surface; I do this to open the wood so it absorbs the stain well. I have not had any problems with lightening, but I think if I were working with a piece that was not going to be refinished just cleaned and re oiled I would use a lower concentration. As you know the Tung oil is a little less forgiving; it can't be left on the surface as long before it must be worked in. Another little thing that has worked well for me is to add a wee dram of stain to the oil when first oiling a freshly stained surface. I would think that would also work very well after cleaning a piece.

Thanks again,

Stephen