[Two crossover circuits for Model 24?]

Just to let you all know, I replaced the 4mfd capacitors with new Erse caps and the 24s sound much better. A very tight sound with plenty of bass and much nicer highs than before. I know it's apples and oranges, but I was A/B-ing them with my large Advents and while the Advents had the much deeper bass, the KLHs had better mid and highs. I bought caps for the Advents as well to reach the minimum order and just got done with them. Now the highs and mids are where they should be.

Those little KLH 24s really are amazing little speakers - with a total investment of around $15 I'm one happy camper!!

Rex

[Two crossover circuits for Model 24?]

I'm pretty sure KLH speakers were sequential for each model.

AR speakers of that era certainly were. The poorest selling model, the AR-5, sold around 50,000, which was reflected by the serial numbers. Other AR models, such as the AR-4x, sold around 400,000, with cabinet serial numbers showing same.

Roy

Wow, that's a lot of speakers. Going by the 2 year model life, I didn't think they would have made that many.

So, I wonder how many had the simple circuit compared to the one mentioned most on this site?

Rex

[Two crossover circuits for Model 24?]

No dates on the woofers. The serial numbers on the rear of the cabinets are 020872 and 020873.

Roy

Mine are 114266 and 114267. The numbers must be some sort of code rather than sequential - that would have been over 93,000 speakers made between ours which is highly doubtful.

Rex

[Two crossover circuits for Model 24?]

Coincidentally, I've just been given a pair of KLH 24's to check out for Ebay's "Vintage AR". The crossover cap in each cabinet is a dual 2uf npe wired in parallel to produce a total of 4uf. They are not out of spec by much, but I will replace them with single 4uf film caps. See photo of crossover with original cap...

Roy

Well, I'm just going to replace the 4uf caps and go from there. Roy, did you find a date on the woofer? Mine were from Feb. 1969.

Rex

[Two crossover circuits for Model 24?]

Nice find!

First of all--that capacitor absolutely must be replaced. It's PVC and they always leak (or worse--I had one explode!)

Your photo is a little unclear but what's throwing you off is--that's a double cap. A common lead comes out of one end and there will be two leads coming out of the other. The cap itself will be marked with the 2 values. Just replace it with an 8uF and a 16uF. I used Caeli caps from Madisound in mine. They are inexpensive and the ESR is close to the originals.

Kent

Thanks Kent, that is exactly what I was expecting based on your previous posts, but it is a single 4 ufd cap and no resistor. I found a thread on AudioKarma with the same thing.

Rex

[Two crossover circuits for Model 24?]

Hi, I'm new to the site but I have been lurking since I picked up a pair of large Advents at a garage sale last Summer. I recently came across a pair of KLH model 24 speakers at a thrift shop for $5. When I got them home, I hooked them up next to my wife's Boston HD8s which are similar. They both worked and the bass was fine but the highs left a lot to be desired. The tweeters were working so I started doing some searches here and on AudioKarma. It looked like I probably needed to replace the caps in the crossover.

I found a great thread showing the crossover with the inductor, resistor, 8, and 16mfd caps. Well, I removed the woofer on one and checked out the crossover and it had only the inductor and a single cap. These speakers have the screw terminals which it seems was standard on the stand-alone versions rather than the RCA jack found on the speakers that came with the system 24.

My question is, is the 4 component crossover designed to match the system? Is there an advantage to using the more complicated circuit on the stand-alone or should I just replace the single cap?

Thanks,

Rex