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mboxler

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  1. The Heresy I and II used autoformers. Klipsch went to series resistors starting with the Heresy III. The crossover in your Heresy IV is pretty complex. Are you asking if autoformer(s) could be used in those?
  2. Yes you do. One of the few things ALK stated that I agree with is that the K33 looks like a 1mh inductor with a DCR of 6 ohms @400hz. What equation are you using? Here's an LTSpice simulation of an AK-3 woofer low pass as well as a REW voltage plot. Mike
  3. If you are referring to the electrical cutoff, it's closer to 350hz on an AK3 Klipschorn. I imagine it's still close to that on a La Scala, but I'll measure the impedance of a K33 mounted in a La Scala later today to be sure. Mike
  4. As is usually the case, the truth tends to be somewhere in the middle. To satisfy my curiosity, I ordered a pair of Altas PD-5VH's. Below are plots of a new PD-5VH (Blue) and an old K55V push pin (Orange). Both measurements start at 300hz on a K-400 horn with no filter. I'll let you decide the frequency responses of each driver. Again, the Altas driver is brand new. I don't know if the FR will change over time. Mike
  5. After all that drama, I forgot to answer the other part of your question... 1) Either add a 10uf to 12uf capacitor in parallel with the main high pass capacitor, or replace it with a 12uf to 14uf. 2) Move the K55V to tap 4 of the T2A. 3) Move the K77M to tap 5 of the T2A. 4) Change the K55V and K77M polarities back to normal. 5) On the tweeter filter, add a parallel 245uf inductor and second 2uf capacitor. Please excuse my poor illustration 😀
  6. It may extend to 6khz, but not gracefully. Or am I missing something???
  7. I may be a party of one, but I find the AA with those drivers unlistenable. To start with, the K55M's FR extends flat to 6khz compared to the K55V, which starts fluctuating around 4.5khz. I believe that's a big reason why the AL has the steep 6khz high pass to the K77M. The AA's tweeter filter is really closer to a 5khz high pass, and somewhat equalized to blend with the K55V. With the AA, there is an overlap from around 4.5khz to 6khz that I found annoying. I know this because I built a pair of AA's and tested them on my AK-2 Khorns. Again, I may be alone on this, but since you asked 😎 Mike
  8. I assume you have the K55M and K77M? For my own information, does the K77M mount flush with the back or the front of the motor board?
  9. The 4uf capacitor may be too small to work properly with this last change but as always let your ears be the judge.
  10. Yes leave the tweeter on tap 5. Squawker to tap 4. Unfortunately if you leave the back off you’ll loose some base. I’d put the back on with only 4-6 screws to ease the process.
  11. We are all noobs one way or another. Yes, db is decibel. Perhaps the squawker dropped by more than I thought. The only other thing would be to move the squawker from tap 3 to tap 4 as well. Sorry. If I had Cornwall's I would try this myself before suggesting the changes. I know it's a pain to remove the back.
  12. On the Type B crossover, the tweeter filter is connected to tap 4 (-3.35db, dotted line). Simply desolder that wire (which is connected to the 2uf tweeter capacitor), and solder it to tap 5 (-0db, bold line).
  13. Moving the tweeter filter from tap 4 to tap 5 will increase the CT-125 voltage by 3.35db. It also drops the K-55 voltage by around 1db. I don't have a Cornwall to measure the actual SPL changes but it's an easy mod to try.
  14. Actually, you have the Crites A-4500's to go along with your CT-125's. It would take some work to convert them to AA's. I like the CT-125's, but found the sensitivity to be too low for the Khorns. It's a great tweeter for the Cornwall or Heresy, if you make tap changes to bump up the voltage to them.
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