KenB

John, Sounds like you have a AK-2. If you haven't popped open the woofer door, that's where you will see the main difference: The AK-2 (~1988) version used 2x70uf of capacitance instead of 2x50uF with the same 4mH's of inductance. Minor changes in the squawker: The AK-2 uses a T5A transformer not the T4A. Also the inductor is a 4mH not the 5mH as in the AK-3. The tweeter protective filter is just arranged different: The 2uF cap then the 500uH coil to common, instead of the other way around. You'll probably want to lift the red wire to eliminate this from the circuit based on the postings of improvement doing so. Of course this leaves the tweeter slightly more vulnerable to mishap. I let Al K. or someone else explain what difference these changes might make in the crossover types, if any. Cheers / Ken

Hi folks, Thanks djk, Randy and Al with all the helpful info & input. Hope to try this AA mod soon and post. My two cents: Keep the paralleled caps of equal or better quality when trying mods involving capacitors. Even a correct value can be rejected because you can readily hear quality differences in them with Klipsch. Try to use caps of the non-metalized type for this if you can, using film/foil dielectrics like polypropylene or polystyrene opposed to say mylars. Alligator clipping a 4uF in parallel with the 2uF is fine to do, and one can lift a lead and drive yourself crazy with a back and forth comparison. Just don't short the loose clip end. Cheers / Ken

djk, Did I miss something? I saw the PWK patent: Figure #5 showed a 0.23mH in series with the squawker +, and the cap was a 4uF (not a 2uf) to the common. -Ken (gad these UBB codes are a pain)

JLOUNDER, I think the P-trap config. you saw was a 0.25mH inductor (after the stepdown trans) in series with the squawker + with a 4 uF cap in parallel to the common. "Sorry I could not draw circuit out sucessfully using the BB post system". Al K. or somebody, let me know if this is wrong. Obviously there are other P-trap designs. Though this is the one Al tested out I believe. Cheers / Ken

goto6, I've heard the Luxman 3045's on horns. They didn't put up a good fight against my mod'ed MC-30's. Resolution of complex material was quite poor in comparison. They ran hot too, and it appeared to eat tubes quickly. OTOH, a MAC can have good tubes even after 20 years of use. Of course re-bias pots should be added to the MC-30's if you want to keep tubes over such a period of time. Just my observations at the time, and I never heard a tube mod'ed Luxman. Ken

DJK & others, Okay, I know dynamatting works for my older set of Khorns & La Scala's which have the cast aluminum K401 mid horn. Makes your system sound more like a 2-way speaker, & smoother. I also have a newer set of Khorns with the PLASTIC squawker. Is dynamatting them the way to go ala the metal horns? It seems like since it's a different animal, damping should be handled differently. Also, happened to be into my La Scala bass compartment and noticed that the scews could be tightened several turns against the wood face, and since I thought they should be tight, I did so. Is there a proper "torque" setting for the gasket interface? Or is a reasonably tight interface always better? Wondering if I did the right thing, and since I did a bunch of other stuff at the same time I can't listen to the change easily. Thanks for your responses..Ken

gto6, I replaced the caps years ago before I became more obsessed with part quality, I used Sprague Metalized Polyprops (a decent cap). I also put in a bias reostat, and used new carbon film resistors. Depending on what MIT caps you put in will affect the quality of sound out. I don't like metalized caps (except the Harmony), but good MIT Polystrene or Polypropylene film/foil is good. A PIO Jensen CU foil can cap in a critical area would be would be great sounding. The rectifier tube is not as important for good sound, as long as it does the job. Driver tube quality and signal & output tube quality is much more important from my experience with these amps. BTW: Don't put these amps side by side, the 6L6's can interact and possibly even fail! -Ken

Joe, I've replaced my K-77M's with JBL slotted compression horn tweeters: JBL model #2405H, they are easily much better than the Klipsch/EV's. $225 ea. from JBL Pro dealer I mount mine above my Khorns. But there just isn't quite enough space to cut a round hole in the middle of the retangular hole and mount them like: =O=s> The diam. of the JBL tweeter front is 3 inches. I would mount any NEW tweeter above the speaker & just disconnect the stock ones. Don't destroy the value of the "Belles" in any way. So Joe, wacha got for tube equipment -Ken

Vibrapods are good cheap isolators, you'll need the hefty variety. I've had the MC-30's. You will not be sorry, I hear the autoformers were the best McIntosh ever made. I drew a pattern of the circuit board with the simple hung on parts by hand (easy). After double checking the positioning, I snipped out every cap, resistor, etc. Next I de-soldered and cleaned up the heavy connection lugs. Finally, just hung & re-soldered the NEW parts. It took only one day to do all this for a pair of MC-30's! The bass and detail were much improved! Tubes used might be a consideration as far as susceptability to vibration. Don't use the Chinese 6L6's or KT66's. The Svetlana's might be a better sonic choice, as well as being much less microphonic. Good luck & enjoy!....Ken

Yes Peter I'm talking about Klipsch Cornerhorn build styles: Model A: ? = My question Model B: Built in riser between bass section Model C: Without above Model D: Decorator's model, with no squawker tweeter cabinet in black only and no side grills or cloths. I just bought a JBL compression horn slot tweeter (JBL#2405H) to replace my stock T35a/K77-M's. The question of breking-in new drivers came to mind. BTW: IMHO the JBL trounces the T-35 type, since I've heard many models of the old EV's, and it doesn't come close to this JBL model. Approx. $225 ea. from your friendly JBL Pro dealer. -Ken

Guy, I just tried the JBL 2405H's in my Khorns! They are BETTER than the K77M's or Alnico T-35a's. They are the only reasonably priced tweeter that I found with specs that pretty much match the Klipsch requirements: 6.5kHz-21.5kHz, 105 dB/1W/1M, and 8 ohms Retail = $306 each JBL Pro site Actual dealer price = $229 each Yeah, I know ideally you should cross at 5500-6000Hz , but I hear no problems. This is a very nicely made compression horn tweeter. Sounds nice and sweet and open, just lovely with female voice, strings, high hats, etc. I found it had decent dispersion qualities. The JBL blends seamlessly with mids and lows to sound like it's a two-way system, even though I mount it above my Khorn. MarkF..Did you see that "Raven" makes a model R-3 Ribbon which handles the mids and highs! Raven model R-3, 60# each! 500hz-30kHz, 99 dB sens./1W/1M Price = $1650 each Really not that bad a price. Just get a Klipscorn base, add the R-3 and Bi-amp. Wow, this COULD make for a great two-way system! http://www.zalytron.com/ -Ken

Anyone know whether new drivers sound better over time? Most electronics and some mechanical equipment require a break in period for best performance. Extra credit question: Was there ever a model (A) type Klipchorn? I know there were (, ©, & (D) models. Thanks / Ken

Al, I had an instant on TV, it went up in smoke while OFF---uh half on! I think that concept was a safety issue...so the half-ons were taken all-off in the end. -Ken

Ditto with the statements above. Plus amps do draw a bit of power = extra dollars, and tubes lose there oomph as their lifetimes come to an end. Gee, kinda like people. The only exception would be if you could leave the tube filaments alone always on. Again, it's all the turning on & off an on that kills the getter (stripping). -Ken

Boa, I assume you have a cable box hooked-up. They're notorious for passing AC hum to the rest of a surround system. Check it out as a last resort. I have the Velodyne 18"er and it hummed, but a non-grounded 2 prong adapter fixed it. Try breaking the RCA ground on one side of a suspected interconnect as an alternate fix. Good Luck / Ken