Deang Posted March 22, 2004 Share Posted March 22, 2004 I'm not even in the same league with you guys, I'm still down here working on my White Belt. I'm just a "piddler", but not half bad at it. I just extrapolate from everything I digest, and seem to come up with some decent recipes. Since I primarily mess with the much later Fortes, KGs, Chorus', and RFs -- I'm afforded the luxury of "trusting" the circuit somewhat. I've just come to the conclusion that better parts = better sound. I believe that the lower losses of polypropylene film are only partially responsible for this. Yes, things become a little more "forward" sounding, but there also comes an inherent cleanliness attached to the sonic signature that points to something more going on with the use of these parts. With the RF-7s -- things just became so clean and open sounding from top to bottom. I have trouble describing the changes as "hotter", or "brighter". What I primarily notice is the absence of grain, hash, and high frequency "ringing" at higher SPLs. I think I probably believe some things that most of you don't. I do have some questions from what I've seen in this thread -- and I just want to make sure I'm drawing the right conclusions. Apparently, the AA network was used with different driver combinations. Considering the differences found with some of the drivers, I'm confused by this. Hell, I can't even keep them all straight. So what about that damn screw? Yank it, leave it? How do these choices impact the inductance? Zener diodes bypassed -- so what should AA users put in place for tweeter protection? Trey mentioned a polyswitch in parallel with a resistor. Good, bad, indifferent? Which polyswitch (spec wise)? It seems this mod is best suited for those using the alnico tweeter (what the heck is that thing -- KV-77-V). Lastly, this appears to be a nice mod, but if someone had a choice between rebuilding their AA's from the gound up with good parts, and buying a set of ALKs -- it would appear the ALKs are the superior choice. Yes? Quote Link to comment Share on other sites More sharing options...
3dzapper Posted March 22, 2004 Share Posted March 22, 2004 "Apparently, the AA network was used with different driver combinations. Considering the differences found with some of the drivers, I'm confused by this. Hell, I can't even keep them all straight." The only different drivers used with the AAs were the K77 & K-77m Khorns Lascalas and Belles all sed the same drivers with the AA: K-33; K55v: K77(m). A few may have used the K55 with the solder terminals and different phase plug but this did not change the crossover requirements. "So what about that damn screw? Yank it, leave it? How do these choices impact the inductance?" Al K says yank it. So yank it.(He has the test equipment) "Zener diodes bypassed -- so what should AA users put in place for tweeter protection? Trey mentioned a polyswitch in parallel with a resistor. Good, bad, indifferent? Which polyswitch (spec wise)?" If you are using a lower powered amp (50WPC or less) don't worry about it. Otherwise limit tweeter power to 4watts on an original K-77 Alnico (0.5A). If the diaphram has been replaced with a ribbon wire lead or on K-77m's 10 watts (1.25A)should be OK. "It seems this mod is best suited for those using the alnico tweeter (what the heck is that thing -- KV-77-V)." See above. "Lastly, this appears to be a nice mod, but if someone had a choice between rebuilding their AA's from the gound up with good parts, and buying a set of ALKs -- it would appear the ALKs are the superior choice. Yes?" Maybe. I have both. I like my AAs with F&Fs and bridge and I like the ALK's ability to play with the squaker output. I am using the ALKs now because when I put damping material in the bass bin and on the woofer basket the appearant bass output was lessened due to the reduced cabinet resonance. I took 1.6db off the squaker to balance the sound to my liking (Setting 4 & X). I was using the 5 & 2 setting previously. I haven't run a sweep lately but I'll bet it is flatter than before especially under 400Hz. Rick Quote Link to comment Share on other sites More sharing options...
Shock-Late Posted March 23, 2004 Share Posted March 23, 2004 screw?? what screw??? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 23, 2004 Share Posted March 23, 2004 Shock, He's talking about that stupid steel wood screw holding the tweeter inductor to the board. Al K. Quote Link to comment Share on other sites More sharing options...
Shock-Late Posted March 23, 2004 Share Posted March 23, 2004 thanks Al! wow... ok, just removed the screws. sure sounds different, didn't really expect it would work! how come??? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 23, 2004 Share Posted March 23, 2004 Shock, That screw acts like a high lossy short circuited turn of wire. It gets energy induced into it. Steel is a bad conductor and the eddy-currents induced into it are lost. It also changes the inductance a bit becasue the edy-currents induce a current back into the coil that are opposite the intial coil. These eddy currents are the reason iron core inductors have laminated cores. Each layer is insulated from the others so large currents can't flow in the core. The screw is a solid piece of (bad) conductor. Steel also has a "permiabiltiy" factor that changes inductance too. BTW: sometimes Klipsch used a brass screw. That's not nearly as bad. Brass is a much better conductor. Al K. Quote Link to comment Share on other sites More sharing options...
Shock-Late Posted March 23, 2004 Share Posted March 23, 2004 That's great to see how some ridiculously minor changes to a crossover can have such an impact on the sound. I removed the zener two days ago, now this, and this almost makes my scalas sound like i changed the tweeters for something better! Now i'm on my way to buy some decent pair of 1uF poly caps. thanks again, Al Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 23, 2004 Share Posted March 23, 2004 Curses.. I think I may have shot myself in the foot. If I keep improving the AAs nobody is going to be buying my networks! Al K Quote Link to comment Share on other sites More sharing options...
3dzapper Posted March 23, 2004 Share Posted March 23, 2004 Rick Quote Link to comment Share on other sites More sharing options...
BEC Posted March 23, 2004 Share Posted March 23, 2004 Al, What you said has prodded me into more testing. I measured the 245 uH coil without a screw and got 244 uH. Placed brass screw in the coil and it did not effect the reading at all. Placed a steel screw in the coil and read 387 uH. Here is the kicker. The brass screw came from one original Klipsch AA crossover and the steel screw came from another original Klipsh AA crossover. I guess my question would be "Did Klipsch want a 245 uH inductor or a 387 uH?" Seems they used both. Perhaps either value is fine? Perhaps manufacturing lost the reasoning for using one screw or the other. Bob Quote Link to comment Share on other sites More sharing options...
Shock-Late Posted March 23, 2004 Share Posted March 23, 2004 ---------------- On 3/23/2004 8:47:22 AM Al Klappenberger wrote: Curses.. I think I may have shot myself in the foot. If I keep improving the AAs nobody is going to be buying my networks! Al K ---------------- LOL... don't worry Al. All this is just tweaking until I have the money to buy you a pair of AlK's (or the ALKit) Quote Link to comment Share on other sites More sharing options...
pdmnz99 Posted March 23, 2004 Share Posted March 23, 2004 hi guys i have read Al K recommending that if one had the type aa, one should do three things -- take the zener diodes off, remove the steel tweeter inductor screw and put a 3.9uf cap across the 2uf cap before the tweeter to bring it up 6uf. has anyone done the 3.9uf mod and also added this new tweak with the 1uf cap? should this be done? i too have added to one uf cap and the difference is not negligible! certainly much more improvement than removing the zener diode and steel screw combined. rgds Peter Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 23, 2004 Share Posted March 23, 2004 Peter, If you have added the 1 uF bridge cap, do NOT add the 3.9 uF cap also. You need to do one or the other. I recommend the 1 uF bridge since it sharpens the skirt as well as flatten the passband. The 3.9 mod actually makes the skirt LESS sharp. Al K. Quote Link to comment Share on other sites More sharing options...
pdmnz99 Posted March 23, 2004 Share Posted March 23, 2004 hi al thanks. i have put on some no name polycaps from the local electrical shop for the moment while waiting for north creek music to ship across the harmony caps. will be updating the woofer inductor to air core shortly too -- and freshen up the internal speaker wiring with wire from NC music too. then i might try the type A setup to see if it might suit my system/room/ears better. thanks to all the information gleaned from the forums. you guys are the real deal for a parts swapper such as myself. Quote Link to comment Share on other sites More sharing options...
Benesesso Posted March 27, 2004 Share Posted March 27, 2004 Given the price of brass screws, I have little doubt that some beancounter tried his best to keep using steel screws. Fortunately some tech. or someone managed to convince/override him. OK, what happens to an AA if the only changes made are yanking the screw and adding the 1 uF bridge cap? I still have the zener diodes connected. Should I yank them too? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 27, 2004 Share Posted March 27, 2004 Bene, The zeners are a mixed bag.. They really do no harm at all untill you really crank it up. Then you get destortion and maybe even a blown amp. They actually put a short circuit on the amps output when they conduct. It will protect the tweeter though. My advice is to just cool it with the volume control and you're safe with or without the zeners! BTW: It's a completely seperate issue from the other mods to the AA. Al K. Quote Link to comment Share on other sites More sharing options...
cwm Posted March 28, 2004 Share Posted March 28, 2004 I often wondered why people were disconnecting those zener diodes, I assumed there was some real or imagined sonic improvement by taking them out of the circuit. I can imagine the sound levels must be at the annihilating point to actually have them start to conduct!! OR, is there some other reason for those folks taking them out of circuit?? Quote Link to comment Share on other sites More sharing options...
BEC Posted March 28, 2004 Share Posted March 28, 2004 Here is what PWK had to say about the "New" AA network in 1971. Bob DFH01.pdf Quote Link to comment Share on other sites More sharing options...
Shock-Late Posted April 5, 2004 Share Posted April 5, 2004 OK, did the last mod. The bypass 1uF cap. Sounds great; opens up the treble, makes everything more "airy"; I was afraid it would make the treble more proeminent and "in your face" but it just sounds more "elegant" and "sharp". result is actually LESS agressive despites the increased high treble output. So people, yes, ditch the screw, ditch the zeners, put the 1uF! oh, and, about the zeners... I DID hear a subtle difference even at low volumes when I diconnected them; however, it may be only in my head... Quote Link to comment Share on other sites More sharing options...
MGklipsch Posted April 6, 2004 Share Posted April 6, 2004 Quote Link to comment Share on other sites More sharing options...
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