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Bacek

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Everything posted by Bacek

  1. If you want to keep original drivers I definitely prefer what was in Cornwall I (k55/k77, those which where used in La Scalas and KHorns continuously). If you want swaps then it does not matter, cheaper will be better.
  2. Ex Najda DSP, unfortunately dead already so only second hand. Mine works fine so far.
  3. They are looking great. I'm planing La Scalas veneering with American walnut. Had some doubts about it but as we see it looks fantastic. What is the finish on them?
  4. This is nice way to cut gaskets. https://www.ebay.com/itm/221926820295?epid=1141794114&hash=item33abde89c7:g:b40AAOSwlV9WTMDU Although ID will have to be 19mm in this case.
  5. For sure I would check the gaskets first. If those were K-55M not K-55V then sometimes on Ms back cap was ungluing itself, causing distorted sound. Also check if everything is screwed correctly, maybe it's mechanical buzz.
  6. If you put more Danish oil layers, eventually it will look like lacquered/heavy gloss. But smells slightly funny. It's easier to scratch that real lacquer but also easier to repair after.
  7. Original La Scala is simpler (to built). Does not have those miter or dado joints.
  8. For a start auto transformer increases impedance seen by C2. And not sure raw impedance's you have chosen are correct. For ex. K33 is 4 Ohm impedance speaker. Horn loaded it will be higher but it's not the case as it's Cornwall so judging by measurement around 400Hz it's closer to 5 or 6 Ohms. For other it will be similar + additionaly autotransformer impact. K77 impedance looks closer to 7.5. And then other factors needs to be taken into consideration as actual frequency response and more. Calculator you have used is good only for ideal drivers with flat response and same efficiency.
  9. As for accuracy, on my AA crossover, there was factory mounted 14 uF capacitor instead of 13uF as in XO schematics. It was combination of two other values.
  10. If you want cheap, exact 2uF you can search for electric motor start capacitors (Klipsch was also using them at some point, saw pictures of AL-3 with similar type). Those are polypropylene foil capacitors. As bonus the can be easily mounted Klipsch style. with a single screw only.
  11. That may be the picture but they look glossy. So question is if they are stained or lacquered. If second then I would not put oil on it. Will not do anything on lacquered surfices and will highlight flaws.
  12. To get raw idea you can check T2A specs. Shouldn't be far, but this has fixed 4dB attenuation.
  13. Ok, I found another example. This time on K33 (B?) actually. Previous movie looks more professional but treatment is similar.
  14. Found some tutorial on JBL speaker. Probably that part was missed. So for K33 I too should use polyvinyl glue?
  15. For a long time I had 2 square magnet K33 laying in boxes. One is fine. The other had strange measurements, was lacking low frequencies when mounted in La Scala. On closer examination it accrued that cone surround is "untreated", just clean fabrics that leaks air. To me looks like someone did recone but kind of wrong way. Cone part number seems to be same for both 451520-2, although one is R-451520-2 (R recone?). So question is if anyone knows if surround needs to be somehow treated/sealed on recone operation? Or maybe replacement cone should be "factory" treated and someone did something relay wrong with it? If possible I would like to fix that driver. First pic is faulty driver. Second one is working fine. You can clearly see treatment on second one. It glow slightly.
  16. Not sure where you are buying it but current APT driver is not the same as originally used in Klipsch mods. In the meantime (few years ago) Eminence changed to some Chinese supplier and this is actually different driver even though it looks similar. Somewhere here there is Bob Crites thread with measurements of this new one, and it looks inferior.
  17. One thing about T2A. In spec -3dBa setting is documented as "-3" and it's actually -3.38
  18. Another thing I like about FIR filters that they don't change phase at crossover point. So signals from two drivers are always adding or subtracting (depending on a choice) and we avoid those strange wobbles near XO point where phase changes several times.
  19. But in LaScala or KHorn, horn loading increases impedance. So even if nominal free air or infinitive baffle impedance is 4 Ohm when placed inside of a horn enclosure, impedance raises, it can be even doubled.
  20. Tried to play little bit with FIRs and my crossover (Najda DSP). Unfortunately low frequency filtering has huge processing requirements. My XO allows only 1024 tapes per channel, mini dsp 2048. Good starting point would be 10k and more for sub. Anyway FIR's allow for very steep XO points. -90dBa is not a big deal.
  21. Ok but while i remember correctly k55 impedance i k400 there is not more than 10% impedance variance in usable range. Does it this justify that large attenuation swing?
  22. This we actually know. Check PWK article on previous page. Although I never understood this measurement effect and if it's something general or rather it was artifact of that particular test circuit.
  23. "eg build the original Heresy (or Klipschorn) according to its original specs" But what does it mean original specs? For Klipshorn exact set of drivers and horns from 1947? Not sure it's possible and it makes sense.
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