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KLH Model 6 Restoration XO Double Check Please Help!


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I got a load of Caps from PE today and started digging into restoring a set of Model 6 Speakers that I recently picked up. I marked all of the wires before taking apart the crossovers but upon completion of the recap and reassembly I still had no sound of of my tweeter. I was about to pull the resistors and check them on my meter but they looked like they were in good shape so I took another peak at the wiring diagram from the Library. The previous owner or somebody must have got in there and really messed with the wiring. I was confused by the color code when I took them apart so now its starting to make sense. I believe that someone bypassed the tweeter completely giving its hot lead but no path back to the other terminal.

I was a bit confused by the diagram since its from the 3 terminal version. For the woofer I ended up with the (+) terminal going through the inductor to the (+) of the woofer then out the woofer back to the (-) terminal. The tweeter section starts directly at the (+) terminal going through the switch and various resistors and caps then to the (+) of the tweeter out to the (-) terminal paralleled with the woofer's (-) lead. Resistance on the system at the Terminal is about 6ohm. With music it sounds great!

I just do not want to have something hooked up wrong and damage the tweeter over time. The only thing that is sticking out to me as strange is the start of the woofer section. There is a short red wire coming off of the (+) terminal that I simply have wire nutted to the red wire of the inductor. I cannot wrap my head around why that short wire is even there. Couldn't the inductor be paralleled with the tweeter section right at the terminal? The only think that I can think of is for ease of bypassing the inductor or replacing it. Neither of which seems likely.

Are there any 6 owners out there that could chime in and offer me some guidance?

A picture of my Crossover and wiring is attached below and the original manual can be found at this link to the Library:





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From what I've read, there were 2 versions of the Six. The schematic in the Library is for the early version. One word of caution: KLH for some reason started using those stupid metal panels to mount the xo. Be SURE your terminal screws are fully insulated/isolated from the metal.

I found this thread with a photo of the later xo. It may help http://forums.stevehoffman.tv/threads/i-just-finished-restoring-a-pair-of-klh-model-sixes.323259/

There is a comment there that the xo in the Six is the same as the Seventeen. If true that's not surprising since KLH used the same xo in several models. I'll attach the Seventeen schematic below. But there is no inductor in the Seventeen.

Here is an excellent step-by-step write-up of a Seventeen restoration http://audiokarma.org/forums/showthread.php?t=102176



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Thank you very much. I stumbled upon both of these images. It is nice to know that the 17 diagram is correct. I basically looked at the 17 diagram and the 6 diagram from the library side by side to come up with my wiring. The only difference is the Biamp capability and the inductor between the two diagrams from what I can tell. So for anyone in the future that is recapping a newer set of sixes and the speaker leads look like they have been messed with: Model 17 Diagram with the inductor placed in series before the (+) lead of the woofer.

The thread that you sent me was perfect. This confirms that I have the wiring correct. This was the picture that I needed:


I now have a theory about the "unnecessary" red wire. I bet that my 6's were made right alongside 17's They probably used pre-assembled XOs for both. It would save a step in assembly to have the red wire from the (+) terminal attached to all of the XOs. This way the red either gets wire nutted to the woofer (+) in the 17 or to one side of the inductor in the 6. This prevents having to solder a connection inside of the cabinet during assembly or having some XOs with wire leads and some with inductors. I am just guessing here. It would be interesting to hear someone with knowledge on KLH production chime in here.

I learned about the conductive XO plate the hard way when working on my 5's. I forgot the rubber spacers and nearly blew up my Kinergetics KBA-75. Luckily one of its five fuses popped and saved that channel. I now make it a habit to measure impedance across the terminals before supplying power.

Last thought: The audiokarma user suggested soldering the connections before twisting on the wire nuts. Any thought on this. I understand the benefits but am wondering what everyone thinks.

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Glad it all worked out Ben

Although some would disagree, wire nuts are fine. Roy concurs in this assessment. I sometimes use wire nuts, sometimes crimps, sometimes solder & heat shrink.


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