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KLH 12 eq/crossover info?

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Guest

Hello,

I was able to pick up a pair of KLH 12s this weekend, but need information on the cross over (external eq) section. Anybody have any leads?

Thanks,

Leo

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Guest

I have the same situation. I have just received my KLH-12's, but one crossover module is DOA. I am not a technician, but am thinking to replace the caps. One is a '2x4 MFD 50V' non polarized cap. The way it's wired, does this equal a 8 MFD cap? Found any info? Did your 12's come with the crossovers? If not, I may be able to send you a pic. However, a schematic would require some effort to draw up.

Allen Low

Los Angeles, CA

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Guest

If someone can email [ speakerdoctor@hotmail.com] me a clear closeup photo of the crossover it won't be much trouble to pick it apart. KLH's used simple 6dB crossovers most of the time, but it can get confusing when you start looking at the switches and resistors. Another problem comes with the "phase" wiring of the crossover. They often placed caps for mids/ tweeters on the negative leg of the circuit, and the woofer's coil on the positive side. When you look at this with a "modern" frame of mind it can get very confusing.

#1 problem is going to be bad capacitors and #2 dirty switch contacts. Replace the caps with good poly's and clean the switches and that should do it. Coils rarely ever give trouble and resistors can be checked with a simple multimeter. Any "double" caps should be replaced with a single poly cap of the appropriate value [2 caps in parallel = value "a" + value "b"]. This was common in the "olden days" since availability of capacitors was quite limited. Open up an old Bozak crossover from the 50's and you can see whole banks of caps used to build up a single value of 10-20uf for a mid.

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Guest

Hello,

I have a nice set of KLH-12 Speakers. External Crossover boxes work fine!! Really a mint set. Were these the last version that KLH made before Kloss left?? They sound great....anyone know what they are worth, and how much they cost new??????

Virginia, Let me know what you know?????????

oldtubesound@copper.net

or: oldtube_sound@worldnet.att.net

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Guest

I've pickued up a pair today without the external crossover. Can they

be used without it? I suppose it would be next to impossible to find a pair of crossovers. What are my options? Any information, anyone???? Thanks.

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Guest

Since I did not receive any reply I went ahead and connected the speakers directly to my Anthem MCA 5-II power amp. As there are four binding posts on the back labeled A(Black) B(Red) C(White) D(Yellow). I didn't know how to connect them, so I tried some combinations.

Model 12 has 4 drivers on the front: tweeter (T), midrange 1 (M1), midrange 2 (M2), woofer (W). Here is what I found out:

1. D(+) and C(-): T, M1, M2

2. D(+) and B(-): T, W

3. D(+) and A(-): T

4. D(+) and BC(-): T, M1, M2, W

5. D(+) and ABC(-): only T works, rest goes silent.

I don't know what all this mean, but I suspect that there is a crossover inside, as the pitch of the sound from the tweeter changes while trying different connections (for example, when going from #1 to #2).

At the moment, I have them connected as in #3. Even thought this is probably not the best way to connect them, I like the way they sound very much. Now, I really would like to get the external crossover contour box to see what these are capable of. Maybe one of these days I'll get lucky on eBay.

Thats all for now.

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>Since I did not receive any reply I went ahead and connected

>the speakers directly to my Anthem MCA 5-II power amp. As

>there are four binding posts on the back labeled A(Black)

>B(Red) C(White) D(Yellow). I didn't know how to connect

>them, so I tried some combinations.

>

>Model 12 has 4 drivers on the front: tweeter (T), midrange 1

>(M1), midrange 2 (M2), woofer (W). Here is what I found out:

>

>1. D(+) and C(-): T, M1, M2

>2. D(+) and B(-): T, W

>3. D(+) and A(-): T

>4. D(+) and BC(-): T, M1, M2, W

>5. D(+) and ABC(-): only T works, rest goes silent.

>

>I don't know what all this mean, but I suspect that there is

>a crossover inside, as the pitch of the sound from the

>tweeter changes while trying different connections (for

>example, when going from #1 to #2).

>

>At the moment, I have them connected as in #3. Even thought

>this is probably not the best way to connect them, I like

>the way they sound very much. Now, I really would like to

>get the external crossover contour box to see what these are

>capable of. Maybe one of these days I'll get lucky on eBay.

>

>Thats all for now.

From the information presented, I believe that "A" is common to all drivers, "B" is the woofer, "C" is the two midranges and "D" is the tweeter.

Measure resistance from "A" to each of the other leads. A few ohms indicates that each driver probably connects directly to that terminal. If you read a very high resistance or an open circuit (and the driver does indeed emit sound) then there is most likely a capacitor in series with it. This could be the case for the midranges and the tweeter. If you read low ohms, then be very, very careful with your drive level. With no capacitors in the speaker cabinet (in this case) to attenuate low frequencies, you will very probably overdrive and burn out first the tweeter and then the midranges. Your hookup #3 is driving only the tweeter. The change in tweeter "pitch" is affected by the woofer being in series with the tweeter in case 2 and the mids in series in case 1.

I have seen a picture of the Model 12 Contour unit and there are inductors and capacitors in it in addition to the four switches. In other words, indeed a crossover. I have seen Contour boxes on eBay twice.

Bob

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Guest

Bob, Thank you very much for your reply.

Actually, I made a mistake in my post above. I should have said

"I currently have them connected as in #4." which is D(+) and BC(-): T, M1, M2, W.

I measured the resistance as you suggested. I've got,

D-C:20.1 ohms

D-B: 9.9 ohms

D-A: 4.1 ohms

A-B: 6.0 ohms

A-C:16.2 ohms

B-C:22.1 ohms

What does all this mean?

I think I will shelve them for now, until I can get the contour boxes on eBay. Thanks again.

kudret

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The DC resistances of the speakers are as follows:

Woofer:6 ohms

Two mids: 16 ohms (probably both hooked in series)

Tweeter: 4 ohms

These resistances are in line with "nominal 8 ohm impedance" drivers.

Since you read resistance through both the midranges and the tweeter, there are no series capacitors to limit the low frequency energy to them and this puts them at risk of burning out, especially at moderate-to-high listening levels.

Good luck finding/building a contour box.

Bob

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Guest

Thanks again Bob for all the information and the word of caution.

I stopped using the speakers for now.

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