KLH 5 Crossover

[fdejong]

Looking for some help with my KLH 5 crossover.

I get no sound out of either tweeter when they are connected through the crossover, but the tweets both measure on my DMM so I don't think they're dead.

I suspect the xover is faulty in my KLH 5, and when I googled I found others who had this issue.

So, my first though it to replace the caps but ran into these questions:


1.) The wires on the caps don't seem to be marked +/-, does it not matter?
2.) How do I replace the 2 in 1 multi cap?
3.) Anyone else do this before? Any chance it's not the caps?

Here's the xover in question:

 

[tmad40blue]

Replace the caps with the exact values you listed. For the multi-cap, just get two caps. =P

 

[fdejong]

Replace the caps with the exact values you listed. For the multi-cap, just get two caps. =P

Thanks - for the multi, do I connect them in series?

 

[dshoaf]

Parallel the caps to get the proper values when exact isn't available. A couple of other things:

- Terminal strips: Pay attention to any ground lead soldered to the strip that also serves to support the strip. I've seen versions where those depended on the pop riveted leg to serve as the ground return to other terminal strips. Yep, the metal plate then becomes part of the circuit! Get around it by soldering jumpers between those legs so that there's a solid circuit made.

- Check the resistor values and heat the resistors up a bit with a soldering iron while you watch the meter. Values should not fluctuate very much.

- Switch contact: Clean 'em good!

- Seal on the back plate and around the switches: replace or fabricate with new material. The cabinet must be sealed well for the bass to work. You'll get awesome bass out of these things when its done right.

Cheers,

David

 

[fdejong]

Parallel the caps to get the proper values when exact isn't available. A couple of other things:

Thanks for the suggestions.

As for the paralell vs. series - so it's also paralell when replacing a multi cap?

 

[Zilch]

As for the paralell vs. series - so it's also paralell when replacing a multi cap?

Only if they are wired parallel in the circuit.

Bring one or both over here and I'll troubleshoot.

A schematic would be useful.... :yes:

 

[e_just]

I just opened up my 5's and the crossovers look a little different

 

[dshoaf]

There were about 3 different physical versions of the crossover that I have seen and/or read about. They're pretty much the same from my experiences restoring a couple of sets, now.

Here's a schematic that I picked up off the web somewhere where someone took the time to draw up what his was like.

Hope it helps a bit.

Cheers,

David

 

[fdejong]

Only if they are wired parallel in the circuit.

Bring one or both over here and I'll troubleshoot.

A schematic would be useful.... :yes:

Thanks! Watch out, I might take you up on that ;-) Let me order some caps...

 

[Rob-F]

The caps in your speakers don't need to be marked + and - because they are either non-polarized electrolytics, or, in the case of smaller values such as for the tweeter, may not even be electrolytic at all. Thus polarity is not an issue. If the are non-polarized electrolytics, they might be marked "NP" for non-polarized.

In ericjustin's picture, I can recognize the black caps as non-polarized electrolytics. I have run across the same brand in a Dynaco SCA80 amplifier. Notice they are marked with a + at each end.

Capacitors connected in series will have a net value that is less than the smaller one. Two caps in series of the same value will have an equivalent value of half that of either one alone. So two 8mfd caps in series will give you 4mfd. That is not usually what is called for in a crossover.

Capacitors connected in parallel will be additive. So two 8mfd caps in parallel will give you 16mfd. If two leads coming out of one end of the cap you are replacing are soldered together, then they have paralleled them. If not, and they go to two separate places, then they are not in parallel.

Oh, here's thought. KLH used three-position switches for normal, high cut, and high boost. The switches may cut certain capacitors in or out of the circuit. If that's what is going on, then you need to come up with the same capacitor values; but they can be separate capacitors. They don't have to be in the same package. Actually there are schematics floating around somewhere in cyberspace.

 

[Rob-F]

OK I found the schematic. It's on the "Classic Speaker Pages" forum, under "KLH 5 factory schematic."

Yes the sections of the capacitors do go to separate circuits. Looks like you need several 4mfd caps and a 3mfd; and I saw a 25mfd as well. They should all be replaced. You get the best sound by not using electrolytic caps wherever possible. It is not hard to come up with 3 and 4mfd non-electrolytics, such as mylars. The 25mfd will be harder to find in a non-electrolytic; but I have done it by paralleling 5 or 6 caps that add up to the desired value.