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I am working on a project and could use some assistance. First, are there any tools needed/suggested to unscrew drivers? I have a pair of '59 University SA-HF drivers that are mounted to K1000 horns. I have not been able to unscrew them, but would like to mount them to Altec 511B's (I have the flange to threaded adapters). Would an oil filter wrench be a good tool to use?

Second, I need help with networks. I am using K-horn bass bins with K-33-P woofers (for now), the University SA-HF drivers with Altec 511B's, and either University 4401 or K-77 tweeters. I have been told that similiar component configurations sound great with K-500-5000 or older AA networks. Would newer ALK's also work?

Third, if I wanted to use a second tweeter in each speaker, would this be a bad idea? If not, what other changes (i.e. network) would I have to make?

Any and all help is appreciated. Thanks,

Chris

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Chris,

I can't really be sure, but I think my network would work ok with the Khorn bass and the Altec 511B. The only danger I could think of is the area between 400 Hz and 500 Hz may not be completely smooth. You might want to limit how much power you put into them too. The frequency range below 500 Hz may not load the squawker driver completely and the Khorn woofer really starts pooping out above 400 Hz.

Al K.

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Go to an auto-parts store and get a product called "Liquid Wrench." Put several drops on the driver where it screws into the horn. Wipe off the excess. Tap the horn at the driver end lightly with a hammer. Go to lunch. (Liquid Wrench takes a while to work its way into the threads.) It should unscrew pretty readily after that, unless you're seriously cross-threaded. I'd avoid using a wrench because it might deform the housing and scratch the paint. (Of course, I've seen some old-line mechanics remove a stuck oil filter by hammering a screwdriver through it and then using that as a handle, but this proceedure might adversely affect the acoustical properties of the University ...)

Seriously, make sure the University will handle the added power it will receive due to the lower crossover point. I vaguely recall reading somewhere they weren't happy going below 500 hz.

Capt'n Bob cwm35.gif

p.s. If you do decide to try dual tweeters, put them close together, one above the other. You'll increase the output, minimize phasing problems, narrow vertical dispersion, and broaden horizontal dispersion.cwm40.gif

This message has been edited by Capt'nBob on 07-12-2002 at 12:31 PM

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How would I determine if the SAHF drivers could handle the additional power? Or, how would I limit the power to them?

Would K-55-V drivers be a better choice? I'm using the AA networks from my '73 La Scalas now, so using the drivers is not an issue. The SAHF's are out of perfectly good Shorthorns that I could leave intact quite happily.

Thanks for the "gripwrench" link. I have seen similiar intruments for opening jar tops, and they work well.

This an educational experiment for me, and I appreciate the help. I can solder if changing tap settings is needed.

Chris

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I looked up the University driver on the hifilit website (and a big thank you to whoever thought that up!) The original University literature claims the SA-HF is good down to 90 hz. So you should be good to go. I don't know if there are any impedance differences between the Atlas and University drivers or even if this would be an issue if there were - Al K. is much more qualified to talk about that than I am. However, I would assume that PWK had a reason to replace the one with the other.

I'd try them both and see which one you preferred - as the Confidence Man said - "You pays your money and takes your choices."

I'd hate to break up the Shorthorns, though. (Listen to me - just when I'm about to do that very thing with a pair of mine.)

Capt'n Bob

p.s. Try that Liquid Wrench. It really does work well.cwm40.gif

This message has been edited by Capt'nBob on 07-12-2002 at 04:39 PM

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Capt'n Bob, the liquid wrench worked well, and I have listened to both the SAHF and the K-55-V. I will listen further before stating any preference. I'm not sure what I'm missing in the 400Hz to 500Hz range, and have only La Scalas and Sorthorns to compare with these Frankenspeakers. It's a one on one comparison I will make as I am sharing some components.

If I find a combination that I like, I will still return the components to their original configurations and then buy replacements.

Anyone else out there have dual tweeter comments? Thanks,

Chris

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It sounds like you got the SAHF drivers off?

FWIW:

Those TV type grip wrenches are available at Sears Hardware stores, in a set of two. They have rubber straps and work ok.

I also have been using a similar type strap wrench from Pep Boys (Auto Parts store). It has a nylon fabric strap that you wind onto a 3/4 inch square handle that in turn gets tightened with a wrench.

I got this for the chrome oil filter on my Harley.

It can exert serious torque to a round object with no damage.

This message has been edited by k2dx on 07-13-2002 at 07:55 AM

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forgot to comment on impedances....

Use drivers that are the same impedance your crossover was designed for. eg 8 or 16 ohms (not the DC resistance of the driver!).

The cross over point will be very different than the design frequency with a different impedance driver!

University and Atlas both had 8 and 16 ohm impedance drivers......

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  • 2 weeks later...

Thanks for your patience.

Honestly, I liked the SA-HF driver better than the K-55-V when mated to the Altec 511B horn. Still, I put the SA-HF back into my Shorthorn so I wouldn't have 2 sets of speakers disabled for 1 experiment.

I have switched to a University Cobreflex 2 horn with the K-55-V driver and like the sound even better (than the K-55-V with the Altec 511B). Is this what I was missing in the 400Hz-500Hz range?

I have T-30 drivers coming in the mail, and will audition them too. Ultimately the Cobreflex 2/T-30 combo will be utilized in a University Classic cabinet, but for now it's fun to play around with my ears as I switch components.

Chris

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  • 2 weeks later...

Hi Chris.....may I ask what net you settled on? I've had no problems using older AA's with the SAHF/511B combo and agree 100%, the SAHF sounds better in a 511B than the K55V.

I have several spare SAHF's (all 16ohms). Ping me with an e-mail, I'm sure we can work something out if you're interested.

------------------

Ed

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Steel male compression driver threads and aluminum female threads can result in serious galling. To remove the snout froma JBL 2427 I had to put the snout in a large vice and turn the driver with a 36" pipe wrench. Funny thing, the driver cap has indentations that fit perfectly with the jaws, like they knew this would happen sometimes. :-)

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Ed-

I haven't settled on a permanent solution yet, but will send you an e-mail regarding the SAHF drivers. To my ears, the best sounding combination has been the SAHF/511B pairing. The SAHF has been returned to my Shorthorn, and I currently have an Atlas PD4 mounted to the 511B. The T-30 drivers came recently, but I do not like the sound as well. Hopefully, the University Classic project will benefit from them with the Cobreflex horns, as my current project does not.

Tom-

Thanks for the warning about the galling. Can this be avoided with teflon tape? Is there a threaded to flange adaptor available made of steel? Thanks for any further help you may offer.

Chris

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  • 2 weeks later...

Ed!

Many sincere thanks for your help with my current project. You have provided wisdom and advice, appreciated by me and I'm sure by others too.

The SAHF drivers arrived yesterday, and the difference in sound is tremendous! You made my week, and I promise to help you as well as other forum members in any way that I can.

Have a great weekend everyone!

Chris

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