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Modifid Khorns


MarkF

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I though I would share my modified Khorns. I amusing the ALK crossover (very nice), Altec 805b horns, Altec 288k squawker driver, the stock woofer and tweeter. They are driven by Cary 2A3 monoblocks, Cary SLP 98 pre-amp, and a Tjoeb tube CD player. Tubes in the monoblocks and pre-amp are the Sylvania Vt-231 (6SN7) and the power tubes are Sovtek 2A3's. I have KR and RCA 2A3', but Sovtek are by far the best sounding of the lot. The Tjoeb CD player uses the Siemes CCA 6Dj8's.

With the mods these Khorns are very smooth with no harsh edge, much better than the stock. These were bought new Jan 2000 and existed for less than a month in the stock condition.

Khorn2.jpg

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Mark,

Man, that's a serious looking set of speakers! It reminds me of the speakers

I traded in for my Belles. They were Altec "Malibu". They used horns just

like that (they might have been the identical same type) but ran them full

range above 800 Hz. They had two 12 Inch woffers in an open port woofer. You have used the big sectored horn only as a midrange. I

always thought using that big horn full range was stretching things a bit!

Nice!

Al K.

By the way, I forgot to mention that I am proud to have my name on a piece of it!

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I paid $460 for the Altec 805bs and $500 for the Altec 288ks. Both the horns and drivers were in excellent condition. The throat size on the horns and drivers are 1.4. The 805s were a horn that came in the Altec A4s. The A4s were a speaker that contained a pair of 515b woofers Each loaded cabinet weighed 350# each. These were the big brother to the famous A7s. The dispersion of the horn is 40° vertical and 80° horizontal. So they have a nice distribution not too great vertically where you do not want to have reflections from the floor and ceiling. The other horn I considered was the 1005, but this horn is a ten cell and was just too big. The 288ks are 16 ohm with alnico magnets. Each weigh in at 30#, 7.6 in diameter and are very sensitive. Although the 288ks are rated a 500cps they were measured and easily go down to 400cps.

I also have a several other midrange drivers; a pair of 16 ohm, Altec 288c, a pair of Altec 802s 16 ohms, a pair of JBL 2420s 16 ohm and a pair of JBL 2420, 8 ohm drivers.

For a second set of speakers, different room, I use Altec 604s and augment the midrange with the pair of 2420s. The third set of speakers I use a corner Klipsch designed speakers, not Khorns, where I am using Altec 515b woofer, the Altec 802 midrange and a bullet tweeter. Each system is tubed, using everything from a Marantz 8B, in triode mode push pull, to a Audio Research D76A (uses 6550). My other two sets of speakers are non-descript. One is a Bose cube and the other is a Tangent with a Klipsch sub.

In my opinion after having tried lots of stuff is I really like the sound of the Khorns with the 2A3 single ended triode. I am going to call Ron Welbourne of Welbourne Labs this winter and see if it makes sense to build the ultimate 2A3 with the absolute best parts to determine if the Cary 2A3 could be improved upon. And last but not least, the ALK crossovers are a treat to the eye and ears.

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Mark,

It looks like you have had a lot of experience with Altec speaker

components. I wonder if you might be able to identify the drivers that were

on my old Malibu speakers. I edited out some of the comments about them in

my earlier post because it sounded like rambling after I read it a second

time, but they had a sectored horn that looked like yours but were smaller.

Someone had put drivers from a larger horn on them. Do you know what model

number they might have been? I would like to find out what I had. At the

time I don't much about this stuff. It was about 1970 to 1972 that I had

them. For that matter, have you heard of the Malibu model?

Also, when you get some free time, could you please email me a larger

version of the little insert of my network in your photo. I would love to

see how you mounted them.

Thanks!

Al K.

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  • 1 month later...

I have a pair of 288B drivers. Belonged to 1005 multicells. As a combination, I didn't like them. The 288B were not the problem, it's a good unit capable of a linear response to about 12kHz, it's the horn. They were top-hats to a pair of "Voice of the Drive-in" units I purchased years ago at a church auction. Still have the 288Bs, sold the rest of it. Good driver.

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quote:

Originally posted by Al Klappenberger:

Mark,

DAAAHH! How dumb can I get. I just realized the sectored horns in my Altec Malibu speakers where the 800 Hz jobs. Yours are the big 500 Hz version!

I think I need another cup of Coffee!

AL K.

Huh...Al, you sure need to modify the "standard" AlK crossover if you want to use the Altec driver, don't you?

Also, the midrange horn cut-off is 500 Hz, and the cross-over freq. is 400Hz...so, there should be a mod here too?? Would the basshorn be able to go up to 500Hz?

Frans

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Frans,

The pictures of Marks's new squawker horn reminded me of the Altec speakers I had years ago. They are long gone now though. They had a smaller horn and different driver. After thinking about it a while I realized the difference. The new horn and driver Mark has will operate over the same range as the Klipsch drivers and are the same impedance, so no mods were required to my network except changing the taps.

Al K.

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quote:

Originally posted by Al Klappenberger:

Frans,

The pictures of Marks's new squawker horn reminded me of the Altec speakers I had years ago. They are long gone now though. They had a smaller horn and different driver. After thinking about it a while I realized the difference. The new horn and driver Mark has will operate over the same range as the Klipsch drivers and are the same impedance, so no mods were required to my network except changing the taps.

Al K.


I knew about your first error, Al, i was just asking if a 288 altec could be use with an AlK x-over and also if a 500Hz horn could go down to 400Hz...anyway, you answered to both. Thanks biggrin.gif

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Frans,

The woofer / squawker crossover in my network is only 6 db / octave. The roll-off of the horns is the main factor, so it will work just as well for 500 or 400 Hz horns. The squawker horn in my Belle Klipsch is 500 Hz (K501) and it works fine in it.

I had an inquiry a day or so ago asking if an 8 Ohm driver could be used. After some computer analysis I found that only tap changes would be needed. So I can say it will work with most any good quality driver.

Al K.

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The Cary 2A3 is a very nice single ended triode amp, especially, if you spend the time and get the highest quality 6SN7 and 6SL7. In terms of how is compares to the ARC D76A, the D76 has lots of power but is lack coherence. With the 2A3, I can hear the individual pipes in pipe organ pieces and jazz is phenominal.

I have just decided to order the Welborne Moondog amp with the ultimate upgrade kit. I think it could improve the sound even more. Once I receive it and build it I will post and let all know.

As far as the Altec 288k's with the 805b horns, I have tried many combinations and find the eight cell horns do a great job of not beaming and they are very well damped so no need for dynamat.

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  • 2 years later...

The Welborn amps are better than the Cary SE2A3's, especially in the bass region. The mids and the highs are very similar but the bass is deeper and tighter.

It interesting how Q-Man and others are learning of the Altec 288's and the 805b horn. I had a audiophile friend of mine measure my system and he could not believe how could they sounded. His only suggestion was he thinks I should bi-amp with solid state on the woofer. It's a tough sell for this SET guy.

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