KLH Model 5

[Guest pbda]

I've just come into possession of a pair of Model 5s dating from the mid-seventies. All drivers work fine on one speaker, but on the other the tweeter and two midrange drivers are dead: no sound at all coming from them. The woofer seems to work fine.

The fact that all three smaller drivers are inoperative makes me suspect that the problem is something other than the drivers themselves.

I've tried manipulating the switches on the back of the cabinet, with no success. Can those of you with more experience in these matters opine on what might conceivably be the problem and how much it might cost to put it right?

Many thanks.

[Guest frleand]

The KLH model 5 are beautiful speakers and you should try to get them working. Disassemble the driver units from the cabinet and test each of them separately directly on your speaker leads (low volume - and don't make the 2 leads get in touch with each other - your amp might blow up). If they play, they are OK. If not......

If they play your problem is internally in the speaker - most probably the x-over network. My bet is that the tweeters and midrange are "blown".

Best Regds

Fred

Norway

[Guest pbda]

In the event that the tweeter is blown, does anyone know what other KLH speakers used the same tweeter as the 1970s era Model 5?

[mrdb]

I renovated a pair of Fives last year. I have a write-up in the KLH section, including schematic. Both of my tweeters had no output. It turned out to be a dual-section non-polar electrolytic capacitor that was defective in both systems. I replaced all of the caps in the crossover with polypropylenes that I obtained locally here in southern California. This fixed the problem. Some people feel that capacitor dielectric matters in the voicing of the speaker. If you feel this way, then use non-polar electrolytics instead.

Check your surrounds. I found that the treated-cloth surrounds were too porous and not providing a good acoustic seal for the woofer and two midranges. The coating had flaked off in many places. I tried some glue, diluted with water, that was recommended by one of the speaker reconers but the system resonance is now too high because the glue is stiffer than the material originally coating the surrounds. I proved this by measuring the impedance peak at resonance and then wetting the woofer surround with a little water on my finger. The wet resonance was right where it should be at 44-45Hz, and was about 20Hz higher when the surrounds dried. I am going to try to remove the glue or replace the woofers should that fail. The moral is, be careful what you apply to the surrounds.

The speakers sound very good in spite of the resonance shift.

Bob

[soundminded]

The tweeters are the same units found in model 6 and 17. The midrange is the same driver found in the table radio used as a full range driver (You need 2.) Probably the same as in model 12 and some portable KLH radio/phono systems as well.