Doug Posted October 13, 2016 Share Posted October 13, 2016 I received my Cornscala-Wall Universals from ALK a few months ago and the large capacitors in mine are 47 µF. I remember talking to Al about my speakers (Klipschorns) when ordering them, so maybe he is choosing different values to suit different speakers after all? Also, I just finished up converting my original AA's to "super AA's" according to the schematic on Al's website. These have a 33 µF capacitor. I did a quick test with a universal in one Klipschorn and a "super AA" in the other, and then switched between channels while listening to the same song. Both networks sounded VERY similar. I may have perceived slightly more bass from the universal, but this could easily have been due to differences in the room (my corners are not identical). To do this correctly, I wish I had a switch that could allow both networks to be hooked up to the same klipschorn. The $99 super AA upgrade that Al is offering is quite a bargain by the way. I think I actually spent more than that on parts for my DIY project (equivalent parts used), and the solder joints and wire routing on my universals from Al are definitely prettier than what I was able to cobble together. 1 Quote Link to comment Share on other sites More sharing options...
Deang Posted October 14, 2016 Share Posted October 14, 2016 4 hours ago, Doug said: I received my Cornscala-Wall Universals from ALK a few months ago and the large capacitors in mine are 47 µF. I remember talking to Al about my speakers (Klipschorns) when ordering them, so maybe he is choosing different values to suit different speakers after all? Yes, looks like it - and that's a good thing. He should be doing the same with the Super AA. Nice first post btw, thanks for your response. Quote Link to comment Share on other sites More sharing options...
Doug Posted October 14, 2016 Share Posted October 14, 2016 Thanks Dean! I've been lurking around for a while and thought I could provide some useful info on this 1 Quote Link to comment Share on other sites More sharing options...
Honeybadger Posted October 14, 2016 Share Posted October 14, 2016 3 hours ago, Deang said: He should be doing the same with the Super AA. I thought the idea of the Super AA was to simply upgrade an already existing crossover. Moving the crossover points would require changing additional parts like the re-used inductor which would add additional expense. For the $$ the super AA is a bargain, I forgot this was an option until now. I still have a set of AA's from my Lascala's I was going to rebuild myself, but I don't think I can do as cheap. 8 hours ago, Doug said: The $99 super AA upgrade that Al is offering is quite a bargain by the way. I think I actually spent more than that on parts for my DIY project (equivalent parts used), and the solder joints and wire routing on my universals from Al are definitely prettier than what I was able to cobble together. Thanks for the heads up Doug. Your network turned out better then mine! Don't use hot glue like I did... Messy HB 1 Quote Link to comment Share on other sites More sharing options...
Deang Posted October 14, 2016 Share Posted October 14, 2016 4 hours ago, RoboNerd said: Deang, Didn't PWK install the AA crossover in the Klipschorn, the LaScala and the Belle Klipsch? >>> Yes. The Klipschorn has a 400 Hz crossover. I think the Belle Klipsch crossed over at 500 Hz. It has a smaller squawker horn. >>> No. Same network, same crossover point. The model number of the horn is not necessarily analogous to the transition point. I haven't seen different version of the AA with different capacitor values from Klipsch. >>> We weren't comparing the Klipschorn and the Belle Klipsch, but the Klipschorn and the Cornwall. Why should ALK change that big capacitor from 33 to 47 uF between these speakers in his low priced rebuild? >>> Because as mentioned before, 33uF makes sense for the Cornwall (600Hz), but not for the other three (400Hz). Why is the 33uF value used in the Super AA, which was designed for the Klipschorn, Belle Klipsch, and LaScala? Why should he offer the choice in the economy version of the universal? >>> Because one is right and the other isn't. I was building the Universal under license using parts I preferred. My cost was close to some of his gentle slope options, so he decided to "economize" the build. For some reason, he wanted to go back to building a network that he had repeatedly told me he couldn't stand building, and considered to be "obsolete". I had no interest in building it after that point anyways (I don't do "cheap") - especially since I still had my Klipsch builds and the SuperX (which I built with parts that are worthy of these loudspeakers, and actually do them justice). And yes, whether Universal or SuperX, I always adjusted the values for the loudspeaker I was building for. Quote Link to comment Share on other sites More sharing options...
Deang Posted October 14, 2016 Share Posted October 14, 2016 2 hours ago, Honeybadger said: I thought the idea of the Super AA was to simply upgrade an already existing crossover. Moving the crossover points would require changing additional parts like the re-used inductor which would add additional expense. For the $$ the Super AA is a bargain, I forgot this was an option until now. I still have a set of AA's from my Lascala's I was going to rebuild myself, but I don't think I can do as cheap. Al wanted to use the Super AA to create an entry level build to compete with Bob (Crites). However, I couldn't bring myself to building that way. After several months, people were openly reporting that it sounded better than the Universal. Al was pretty irritated by this, and made me rename it to "ALKJr", hoping it would boost Universal sales. It didn't work. The current Super AA that Al is offering IS a good value, and I hope he has to build a lot of them. :-) Quote Link to comment Share on other sites More sharing options...
Honeybadger Posted October 14, 2016 Share Posted October 14, 2016 Dean, I think you are missing the point. I was referring to the Super AA exchange. My point is you can't change the additional parts to move the crossover frequency and stay at a price point of $99 Its like taking my bicycle in for a service, then ask them to change my gearing and not incur any additional costs. Sorry for the confusion. HB Quote Link to comment Share on other sites More sharing options...
Deang Posted October 14, 2016 Share Posted October 14, 2016 Meant to address that. No other parts need to be changed. IOWs, you can drop a 47uF in there and nothing else changes. The difference in cost with that particular brand of capacitor is $4.00. Quote Link to comment Share on other sites More sharing options...
Doug Posted October 14, 2016 Share Posted October 14, 2016 I think it is possible that Al varies the value of that capacitor in the super AA's he rebuilds based on the speaker they will be going in to. The ones I put together were completely DIY, based on the schematic from the ALK website, which might not be the only way he does them (purely speculating here). On the other hand, from what I have read on the ALK website, Al doesn't seem to be the kind of guy that readily accepts alternatives to the values he calculates for these sorts of things, and it seems like based on his math, the values of capacitors and inductors need to have very specific relationships to each other... Also, doesn't the stock AA found in the Klipschorn have a 13 µF cap in this position? I'm way out of my depth here, but wouldn't that make the crossover frequency even higher between the woofer and squawker than either of the cap values we are talking about here in ALK networks? Quote Link to comment Share on other sites More sharing options...
Doug Posted October 14, 2016 Share Posted October 14, 2016 Good find RoboNerd! From reading that thread, it sounds like choosing the capacitor value has more to do with cancelling out the value of the inductor + woofer voice coil inductance than it does with determining the precise crossover frequency: "In the Universal network, the entire filter is just a single inductor, so I just subtract the 1 mHy voice coil inductance from the 2.3 mHy inductance required for a 400 Hz crossover leaving 1.3 mHy. That's the value I use in the Universal network. This keeps the constant 6 Ohm resistive impedance when the 24+24 uF caps of the highpass channel cancel the inductance of the woofer filter plus the voice coil inductance." On a related note, it seems like constant impedance is a big feature of ALK crossovers. What are the sonic consequences of non-constant impedance? I've read Al's website, and he says something like "amps don't like it when impedance varies with frequency", but I'm wondering what this really means. Will it make your amp wear out sooner? Does it cause attenuation or distortion of the frequencies where impedance is higher? Lets assume we are running a "worst case scenario" low wattage SET amp for the purpose of discussion. Quote Link to comment Share on other sites More sharing options...
Honeybadger Posted October 14, 2016 Share Posted October 14, 2016 37 minutes ago, wdecho said: Short answer, No. There is some difference of opinions on constant impedance. I am neutral. PWK wrote in one of his Dope from Hope papers how varying impedance is beneficial in some ways in his crossovers. At least that is what I remember from memory, do not ask me to look it up. In theory a constant impedance should be better probably more so with tube amps. I don't know about that, I have had a lot of amps, some have 4 and 8 ohm taps, occasionally 6 or 2 ohm options, but haven't see one yet with a 6-70 ohm tap to deal with the heresy impedance. Although not absolutely necessary, a stable impedance network seems like a good idea to me. HB Quote Link to comment Share on other sites More sharing options...
Honeybadger Posted October 14, 2016 Share Posted October 14, 2016 6 hours ago, Deang said: Meant to address that. No other parts need to be changed. IOWs, you can drop a 47uF in there and nothing else changes. The difference in cost with that particular brand of capacitor is $4.00. I have used several crossover calculators, and I haven't found one yet that says one inductor fits all crossover points. You lost me on this one. HB Quote Link to comment Share on other sites More sharing options...
Deang Posted October 15, 2016 Share Posted October 15, 2016 3 hours ago, RoboNerd said: ... the conclusion is simple. The capacitor value is just not important! It looks like anything from 33uf to 50uf is all ok for any of the networks. Wow. Okay, well then. Quote Link to comment Share on other sites More sharing options...
Deang Posted October 15, 2016 Share Posted October 15, 2016 1 hour ago, Honeybadger said: I have used several crossover calculators, and I haven't found one yet that says one inductor fits all crossover points. PK used a 2.54mH low pass coil for the Heresy, Cornwall, LaScala, Belle, and Klipschorn. However, the primary cap values were different based on what he wanted going to the midrange. The Super AA uses the same 2.54mH coil, always has. Quote Link to comment Share on other sites More sharing options...
Honeybadger Posted October 15, 2016 Share Posted October 15, 2016 You may be able to get away with that on a first order crossover, but it makes no sense. HB Quote Link to comment Share on other sites More sharing options...
Deang Posted October 15, 2016 Share Posted October 15, 2016 3 hours ago, Honeybadger said: I don't know about that, I have had a lot of amps, some have 4 and 8 ohm taps, occasionally 6 or 2 ohm options, but haven't see one yet with a 6-70 ohm tap to deal with the heresy impedance. Although not absolutely necessary, a stable impedance network seems like a good idea to me. If you're running a tube amp with low or zero feedback, then yeah, it will make a difference - but that doesn't mean it will sound bad - in fact - what have we learned over time - "horns love tubes". Most amplifiers really don't care - they deliver what's required - that's what they're designed to do. Quote Link to comment Share on other sites More sharing options...
Deang Posted October 15, 2016 Share Posted October 15, 2016 28 minutes ago, Honeybadger said: You may be able to get away with that on a first order crossover, but it makes no sense. HB All of the networks under discussion use a first order low pass and high pass. It makes sense when you see the acoustic response. Quote Link to comment Share on other sites More sharing options...
Deang Posted October 15, 2016 Share Posted October 15, 2016 7 hours ago, Doug said: ... and he says something like "amps don't like it when impedance varies with frequency" ... BS Quote .. I'm wondering what this really means. Will it make your amp wear out sooner? Does it cause attenuation or distortion of the frequencies where impedance is higher? Lets assume we are running a "worst case scenario" low wattage SET amp for the purpose of discussion. That's about the only scenario where it applies. The frequency response of a SET amplifier with little to no feedback will track with the impedance of the loudspeaker. Quote Link to comment Share on other sites More sharing options...
Doug Posted October 15, 2016 Share Posted October 15, 2016 Looking back at the ALK webpage, I think it is pretty clear that he does build the Cornscala-wall networks to suit the customer: "The low frequency crossover is 1st order at roughly 400 or 600 Hz." I think this explains why the OP's network has the 33 uF cap (he has cornwalls). I wonder what the woofer inductor value is in the OP's network... 3 hours ago, Deang said: That's about the only scenario where it applies. The frequency response of a SET amplifier with little to no feedback will track with the impedance of the loudspeaker. I think I'm actually in a position to test this. My buddy has SET monoblocks and some unmolested AA networks in his Belles. When time allows I want to go over there and rig up a switch to compare the super AA to the stock AA and see if we can hear the difference. Quote Link to comment Share on other sites More sharing options...
Schu Posted October 15, 2016 Share Posted October 15, 2016 does anyone know what the heck a "INFINITE IMPEDANCE REGULATOR POWER SUPPLY" is? Dennis Had is using this terminology... Quote Link to comment Share on other sites More sharing options...
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