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T-35A magnets, and other questions


Rockets

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Can anyone I.D. the magnets on these? Are they ceramic? Alnico? I think I read where the square ones were ceramic, but I can't remember.

Another question I have is on horn lenses. What's the difference between a K-400 and a k-401? Dimensionally would either work the same in a Lascala clone?

Finally, what about using a E. Kappa 15C

{specs: Power handling: 450 watts RMS * Voice coil diameter: 3" * Voice coil inductance: 1.05 mH * Impedance: 4 ohms * Frequency range: 30-2,500 Hz * Magnet weight: 80 oz. * Fs: 36 Hz * Sensitivity: low of 97db@400hz to a high of 105db@1500hz * Vas: 9.8 cu. ft. * Qms: 10.60 * Qes: .31 * Qts: .30 * Xmax: 1.6mm * Dimensions: A: 15.16", B: 13.77", C: 6.125".}

in place if the K-33? Anyone know if sonically this would be a mortal sin? Ths specs seem to be in the ball park of a K-33, but the sound may be another question.

I'm just now in the process of figuring out what it's going to take to build a pair, but fear it's going to be cheaper to buy them used. The offset there is finding an 'affordable' set that shipping won't kill me on.

Tia for the help,

Rockets

post-13284-13819249115362_thumb.jpg

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The "square" magnets are ceramic, specifically strontium ferrite. In case anyone wants to know this much, the process starts with a strontium ferrite slurry. It is poured into a mold and pressed. Then after it becomes solid, it is baked in an oven to make it harder. Then the ceramic is machined into final shape and as a last step, it is magnetized.

Bob

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Yes that is a ceramic or "mud" magnet. The ceramic starts as a slurry, hence the term. This should be the same or close to a K-77M (probably for mud). BTW the earlier round Alnico magnet version from EV was also called an -A. The -B was weaker and the -W still weaker. Klipsch hand picked the best of the units produced by EV. Tighter QC.

The K-400 is cast metal. The K-401 is composite. I don't know if the mounting holes are identical. Otherwise they are.

The woofer you spec. out I don't know. The Xmax is a bit on the low side.

One important issue is whether the electromechanics are good for a 78 square in throat of the LS. From memory the equation is:

St = 2*pi*Fs*Vas*Qes/c

That calculates the optimum St throat area. You have to use Vas in cubic inches and c is the speed of sound in inches per second or 13,500 inches per second. If the result is within 20 percent of 78 inches square, I wouldn't worry.

You'll see the use of these units make the equation dimentionally correct. The 2 and pi factors are dimesionless. The volume (in^3) is divided by inches in the c (in^1) which gives in^2 or inches squared. The c is per second and the Fx is in per second; so the per seconds (1/sec) cancel out. I'm showing off a bit but that is how engineering works for getting the correct things to work out.

Klipsch will sell you a K-33 for about 130 bucks. I went to great effort to build K-Horns and a "bigger Belle" using off the self, commercial items. Was it worth the money. No, but I just wanted to do it myself without the factory.

I used a Pyramid bass driver.

As you recognize, buying a used unit may well be cheaper, though shipping costs do alter the frugality.

Best

Gil

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Wow! LOL! I'm going to have to calc this out when I have a few more minutes and can do the conversions from mm to inches. I've found several specs for the K-33 posted, but not all totally agree. Which to use, which to use...

One has the Xmax rated at 8.20mm while another may only be 4mm. In either case there is a 2X to 5X increase to factor in vs. the 1.6mm advertised by Eminence. Also to weigh in is Eminence claims that they have been historically very conservative in their Xmax figures. I need to run through your formula to find the end result.

If I can get in the 20% ballpark, or change the opening dimensions to match I'll be happy. Really I'm more concerned about sound 'quality'. Supposedly the Kappa's are being sold as an 'upgrade' replacement by a vendor well known to most of you I suspect. (though PE has it for less) Still there's a delta of $60/pr for the Klipsch originals. May not seem like much until you add in all the other drivers etc.

SPEAKING OF DRIVERS! Does anyone know of an equivalent to match the K-55? There is one place that offers an unknown for $79 ea, but w/o more info I'm kinda skeeeeeeeerd. I know there's a pair on ePay, that some one is mighty proud of (or I'm mighty cheap!). Any other known manufacturer & p/n???

Thanks again for the history and engineering lesson!

Rockets

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Thanks Tony and Jonnhyp.

Tony where did you find your Atlas PD-5's? I did a search and came up empty!

It's becoming more clear I may have to stick with the K-33 or K-43. Just trying to save a buck finding an alternate. There seems to be a mix of opinions on the bass response of the K-33...I just find it hard to believe that there is not a alternative available!

Any opinions on using a JBL E145? It's 8 ohm, so I guess I'd have to add an L pad to match the impedence. The Xmax is in line, but the Qts and Qms are much lower (read other opinions where this is a good thing, but not sure!) http://www.jblpro.com/pages/pub/components/eseries.pdf

There's a ton of e-140's on ePay, but the Xmax is out of whack. Don't know the Vas:((

Thanks again

Rockets

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Rockets,

Since you already mentioned the Xmax as 8.20, you may already have this for the K33. I emailed Eminence and asked them for the specs, and this was what they sent back. Maybe it's bogus, but it came from them and they made/make the K33 for Klipsch.

Marvel

SPEC 15162

PART # K-33

RE OHMS 3.39 FS HZ 34.46

LE MH .96 MMS GMS 78.59

QM 7.39 CMS mm/N .2714

QE .410 RMS NS/M 2.3037

QT .390 VAS LTRS 301.66

XMAX MM 8.20 SD SCM 889.59

BL TM 11.88 EBP 84.4

EFF % 2.91 SPL dB 96.6

Wattage 150rms

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Just an update and word of thanks to all that have responded. Note that I screwed up ROYALLY in letting a set of t-35's slide for FIFTEEN dollars. On the flip side I'm amazed at some of the MO'rons bidding on eBay. Example: Someone is selling a pair of new t-35 diaphragm ...Top bid so far is over $80. The funny thing is the same guy has another auction, for the same thing, w/"buy it now" option of only $44.99! Actually, I kinda feel like a moron for screwing up! Damn.

Sorry, got off topic...just struck me kinda funny. Glad to see P.T. Barnum's theory still holds water.

Mean while the search for parts goes on...

There's a set of K-33's for $1ea that need to be reconed on ebay, if anyone has a DIY link for the cone kit. It's the only way to do it, otherwise shipping kills the deal. here's the link

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2557315083&category=47095&rd=1 The same guy also has some dead K-43's.

Thanks again,

Rockets

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