KLH Model 17 tweeters

[Norman Nicolai]

I've been searching the site but have been unable to see a thread about the different colored Model 17 tweeters.

i just purchased a second set of Model 17 speakers and the tweeters are silver colored. The tweeters in my existing Model 17 speakers are black.

Thirty years ago I owned a set of Model 20's, which are almost identical to the 17's except for a 4 ohm woofer, and those tweeters were black also.

Does anyone know if there is a difference between the different color tweeters? Is it merely a different generation of speaker, or are there differences in sound?

BTW, my KLH Model 6 speakers have the silver colored tweeters.

Thanks!

 

[JKent]

I believe it's just painted vs raw. I have owned 17 s with black screens (SN range 56000 to 70000) on the tweeters and others with silver screens (SN 39000 range) and a pair with wildly different SNs but both having black screens (84756 &  31018). I'd also point out that the back plates differ. My higher SN speakers have silver color plates with black lettering while the lower numbers have black backgrounds with silver lettering.

[Norman Nicolai]

Thanks for the info, JKent. I wanted to reply to you earlier, but the site has been closed down. Didn't realize I missed checking in every day until it wasn't there.

The newer Model 17's (newer for me) are the ones with the silver faceplate tweeters. They are still in my garage and I have not yet had a chance to take them apart and look at the SN, since I'm still preoccupied with working on the original 17's I purchased. One of the tweeters from the first set of black screened 17's has a date stamped on the back, April 10, 1969. I've already assembled the other restored speaker, so I don't have a date for that tweeter.

BTW, using the center channel from my Fisher 500B, I connected the finished and assembled 17 to a restored Heathkit W5M mono tube power amp, and it sounded fantastic! Not quite as good as my KLH 6's, the main Left and Right speakers for that setup, but better than I remember my old KLH Model 20's sounding. But that's only from memory, and a distant memory at that, since I got rid of the 20's over fifteen years ago. The equipment I have now, compared to what I owned then, may also account for some of the difference. 

At some point, when everything is done, I'm looking forward to doing a side-side comparison of the two sets of Model 17's. If there is a difference, I'll probably keep the subjectively better set, and either sell or gift the other set. It's funny, I got into this hobby of restoring speakers with the idea that I would sell them after restoration. Aside from the problem of there not being much of a market for the restored items, I kind of like having them around. I may run out of room soon, but I am having trouble parting with my work.

[JKent]

Hi Norman

Apparently my earlier post may not have been accurate. If you look at Service Bulletin 59 in our Library here:   http://www.classicspeakerpages.net/library/klh/other/klh_schematicsservice/klh_service_bulletin_59.pdf

you will see KLH made two similar 2" tweeters; One they just called a 2" and the othe a Model 12 2". They were characterized by different thickness of the top plate used to secure the magnet and "some" Model 12s were marked M12. There is discussion of this in this thread: https://www.audiokarma.org/forums/index.php?threads/klh-tweeter-id-and-repair.492609/

The Model 12 tweeter was used in the Five, Twelve and Twenty-Three while the other was used in the Six, Seventeen, Twenty, Thirty and Thirty-Three.

Two thoughts on this:

1. Color (black or silver) makes no difference.
2. Other than physical appearance, there may be no difference between the M12 and the 2" tweeter but I'm not certain about that. It may be best to have 2 matching tweeters regardless of the model number.

Hope that helps. Your 3-channel system sounds cool!

Kent

[ChrisM]

In actual use there isn't much if any difference between the black frame and the silver however I did measure a difference in resonant frequency between them. The black ones have a significantly lower Fs. Neither type has much of a peak at resonance and the crossover is so broad it just doesn't seem to make much difference. The black ones came in the earlier 17's. The change was I believe in late 1969.