1954 Shorthorn Crossover K1000/5000

[Deang]

I'm building the networks for these speakers: They are done with the exception of wiring up the autoformers (UT 3619).

http://forums.klipsch.com/forums/1/758835/ShowThread.aspx#758835

Stated crossover 'points' are 1000 and 5000Hz. The network uses 2.54mH for the 16 ohm Stephens 103LX, 4uF as the primary, with a 2uF for the University 4401 tweeter coming off input positive and being run full out. The mid-driver is the 16 ohm University SAHF.

A couple of things are throwing me off with this network, and after calling Bob and talking about it, we both decided it made sense that since the tweeter is being run full out that the squawker is 3dB down. This of course assumes the sensitivity of the 4401 being similiar/close to the T35. The thread above mentions an 8 ohm impedance for the 4401, but I wonder about this. The data sheet I have for the Shorthorn doesn't give the impedance of the drivers, but I'm beginning to suspect the 4401 is actually a 16 ohm driver.

The problem really centers around the attenuation level of the SAHF/shorthorn combo. The stock autoformer is not a T2A, and has one less tap: Input tap 4 -- with output taps of 3, 2, and 1. Klipsch has the SAHF coming off tap 2, which should correspond to 6dB of attenuation, if so -- the 4uF primary high pass makes no sense. On that tap, reflected impedance should be close to 64 ohms, which corresponds to a 600Hz transition (not 1kHz).

I'm tempted to just connect the SAHF to tap 4 on the 3619 and quit thinking about it. The 4uF makes sense for that tap. OTOH, the original network skips a tap, and THAT makes more sense for this type of speaker -- but then the 4uF cap value doesn't seem right.

The spec sheet I have doesn't have any specifics on the drivers. So if anyone around here has anything on them that would certainly be helpful.

[Guest " "]

There is some general specs at this link for the SA-HF and 4401, but not sensitivity type measurements. Listed at row #2 for 1950 stuff.

http://www.hifilit.com/hifilit/University/University.htm

Do you have a model and part number for the autoformer? There might be a data sheet for it.

[SilverSport]

Dean,

I am the last person to have an opinion on this as I understand little of what makes or breaks a crossover but I seem to remember reading Bob Crites or someone here who DID know that the earlier (I mean '60's or older) K'Horn tweeters were 16 Ohm as well...I think that would be the correct assumption on your part that they may in fact be 16 Ohm...good luck and I look forward to reading more on this as it progresses.

Bill

[BEC]

Dean,

Since we talked, I remembered that I have a K-1000-5000-W.

This one runs both the squawker and tweeter off the same tap (tap 2) of the autotransformer.

Bob

[Deang]

12 ohm spec on that 4401 is interesting. Nice site BTW, thanks for the link.

Bob, mine doesn't look like that. I'll post a pic tonight. That one makes sense for an 8 ohm tweeter -- but tap 2 with 4uF still bugs me. Maybe the team that built all of these was the same team that built the Cornwalls in the 80's.

[BEC]

Dean,

I am guessing the "W" after the 5000 means something. Does yours have a letter in that place?

Bob

[Deang]

No pics tonight -- the camera is dead and the recharger is at work.

Yes, there is a 'W', but then followed by a '2' which is stamped into the metal plate/label. There is a sticker with the inspection signature and date -- 1956.

Well, I don't see that woofer in that cabinet doing more than 101dB, so I think tap 2 on that old autoformer is 6dB down just like tap 3 is 6dB down on the T2A. The 4uF value is too high for a 1000 cps horn -- but there it is.

The tweeter now becomes more interesting. Your 12-16 ohm tweeter (assuming it was a 4401) being run off the same tap as the SAHF doesn't make any more sense than mine being run wide open.

Guess I'll strap the SAHF to tap 3 and tell the guy to watch his volume levels.

[BEC]

Dean,

I don't know anything about the 4401 except the quote from PWK saying it was a "sad tweeter" but that he used it until something better came along.

I also don't know what speaker the K-1000-5000 that I have came from, but I am going to guess that like the K500-5000 crossovers I have rebuilt, there are several different versions of that one too.

But, I don't agree with you that the same group may have built these that built the early 80 Cornwalls. I am pretty sure that those came out of Mrs. Beasley's Kindergarten arts and crafts class.

Bob Crites

[scott0527]

For what it's worth, the tweeter says 8ohms on the back of the driver.

[scott0527]

Here's a picture of the crossover. Sorry I wasn't around while this thread was up.

[scott0527]

No pics tonight -- the camera is dead and the recharger is at work.

Yes, there is a 'W', but then followed by a '2' which is stamped into the metal plate/label. There is a sticker with the inspection signature and date -- 1956.

Well, I don't see that woofer in that cabinet doing more than 101dB, so I think tap 2 on that old autoformer is 6dB down just like tap 3 is 6dB down on the T2A. The 4uF value is too high for a 1000 cps horn -- but there it is.

The tweeter now becomes more interesting. Your 12-16 ohm tweeter (assuming it was a 4401) being run off the same tap as the SAHF doesn't make any more sense than mine being run wide open.

Guess I'll strap the SAHF to tap 3 and tell the guy to watch his volume levels.

Geez Dean, you don't know anything! It was tap 4. They sound fantastic.

Seriously, thanks for your troubelshooting help and suggestions they really do sound wonderful tonight. I could go on but the album needs flipped. Man do they sound NICE, sad tweeter and all. []

[Deang]

LOL!

Hey, are they still pretty -- that's the only thing I care about.