LoudnClear Posted April 17, 2008 Share Posted April 17, 2008 What do the experienced people with La Scala network experience think I should get as my replacement crossover? I read a thread on the tweeter blowing capabilities of the AL net. One of the tweets in this set is not working, that's what got me looking, so I'm not going to fix the tweet until I get new nets, so which one? BEC, you wrote a while back about a fix Dennis djk posted about a bad solder joint causing the stop band slope to be 6 dB / oct instead of 50 dB / oct? Which node is it on this drawing from that thread? Also, I know its not your drawing, but do you know what is going on with the black wire at node 6 to the left of the big 30 uF cap? Looks like a dead end, where does the connection go? Thanks for the input guys and thanks in advance Bob for you response. Kimball Quote Link to comment Share on other sites More sharing options...
Mike Lindsey Posted April 17, 2008 Share Posted April 17, 2008 I know nothing of any of the networks being made by Bob or Dean, but I have had the ALK Universals for 6 years now and wouldn't trade them for anything (maybe the ES Networks Al is selling today). I am also using Altec 511B horns and BEC tweets, but the networks were bought first, and they made the largest difference of all. YMMV... Mike Quote Link to comment Share on other sites More sharing options...
LoudnClear Posted April 17, 2008 Author Share Posted April 17, 2008 Is Al still selling? I assumed he was done when he was done here. Via Website? Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted April 17, 2008 Share Posted April 17, 2008 Al's Website has three different styles of crossovers available. I had the original ALK's in my 1974 La Scalas, and thought they were excellent . Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted April 18, 2008 Share Posted April 18, 2008 Do you have K55M's? If so you should have the AL-3 per the books. If K55M, most would argue that A or AA would be the network of choice unless you want to go full bore and put in the AL4 upgrade kit and call it a day. Quote Link to comment Share on other sites More sharing options...
LoudnClear Posted April 18, 2008 Author Share Posted April 18, 2008 They're K55M. Do you mean K55V would be A or AA? Quote Link to comment Share on other sites More sharing options...
oldbuckster Posted April 18, 2008 Share Posted April 18, 2008 Ah Yes, the collection grows .................... Way to go !!!!! Quote Link to comment Share on other sites More sharing options...
pauln Posted April 18, 2008 Share Posted April 18, 2008 I chose to switch from the AL-4's and go with Bob's Type A's within minutes of hearing the difference. They are first order 6 dB/octave slopes, lots of overlap between the drivers' ranges, very simple, pure, clear, transparent, dynamic... all the things I want; but keep in mind that I am a gentle SET listener who feels that 1 watt for La Scalas is more than enough. The type A's work extremely well with that. Now if you like it real loud, the AL-4 seems to be designed for that in a couple of ways; the slopes are 36 dB/octave 6th order Linkwitz-Riley which really isolates the frequencies to the ranges of the drivers, which is desired for higher listening levels, and the network itself seems to have been designed to provide a slight boost/extension to the low end. It also provides protection to the tweeters. I can see why the AL-4's might be favored by those who like to put dozens of watts through the La Scalas. Quote Link to comment Share on other sites More sharing options...
BEC Posted April 18, 2008 Share Posted April 18, 2008 What do the experienced people with La Scala network experience think I should get as my replacement crossover? I read a thread on the tweeter blowing capabilities of the AL net. One of the tweets in this set is not working, that's what got me looking, so I'm not going to fix the tweet until I get new nets, so which one? BEC, you wrote a while back about a fix Dennis djk posted about a bad solder joint causing the stop band slope to be 6 dB / oct instead of 50 dB / oct? Which node is it on this drawing from that thread? Also, I know its not your drawing, but do you know what is going on with the black wire at node 6 to the left of the big 30 uF cap? Looks like a dead end, where does the connection go? Thanks for the input guys and thanks in advance Bob for you response. Kimball Kimball, It is hard to pin down just where to do the correction to an AL crossover, because I have seen at least three difffernt designs that were just labeled AL before the AL-2 came out. Poor solder connections seem to be a problem in more than one place on the AL crossovers. On the few AL crossovers that I have rebuilt, I cleaned up and re-soldered all the joints on the board. I certainly prefer just replacing the AL rather than rebulding them. When you get them working as good as you can, you still have AL crossovers. For the replacement crossovers, if staying with a Klipsch design, I would recommend the type A, AA or AL-3. But, just the fact that you have a bad K-77 is not reason to point to the crossover as the problem. K-77 often fail just from old age. The diaphragms in the K-77 are extremely fragile, especially the ones made before EV changed the diaphagm lead wires to the copper-beryllium leads. Bob Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted April 18, 2008 Share Posted April 18, 2008 They're K55M. Do you mean K55V would be A or AA? yes, correction made. The M is a hotter driver requiring a different network. You normally would not want to run K55M with A, AA, AL4 network. That being said, I had Bob's A/AA in my LS K55M's for a couple of years and was very happy with them. My room was very soft, with double padded carpet and 3/4" pine walls though. I doubt whether I would have liked this in a hard-surfaced room. Bob has a good point about just replacing the K77 diaphragm and treating the network separately. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted April 18, 2008 Share Posted April 18, 2008 Well, I'm a type A fan. Especially with the CT125 tweeter which is bullet proof. Quote Link to comment Share on other sites More sharing options...
J.4knee Posted April 18, 2008 Share Posted April 18, 2008 I know nothing of any of the networks being made by Bob or Dean, but I have had the ALK Universals for 6 years now and wouldn't trade them for anything (maybe the ES Networks Al is selling today). I am also using Altec 511B horns and BEC tweets, but the networks were bought first, and they made the largest difference of all. YMMV... Mike +1, I use the exact same set up in my 84's Quote Link to comment Share on other sites More sharing options...
Deang Posted April 19, 2008 Share Posted April 19, 2008 I've buiilt them all and heard them all many times, and I can tell you that telling someone what network they should run is like telling someone what to order off a menu at a restaraunt without having any idea of what they like. After using the ALK myself for almost two years, I found I liked the simple Type A better for 90% of my listening. I even preferred a simplified version of the ALK over the full blown version -- not everything works the same for everybody. People should also know that there are two versions of the ALK (Universal Type A); the original, which most around use, and the version which carries the same name but was redesigned by Al a little over a year ago -- they do not sound the same!! Quote Link to comment Share on other sites More sharing options...
Mike Lindsey Posted April 19, 2008 Share Posted April 19, 2008 I would never tell anyone what they should do or run. I only mentioned what I have and that I like it a lot. I have the older Universals, and know nothing about the newer version. As for listening habits I do "no" quiet listening. None. Nada. All my listening is done from the listening room in the sweet spot at moderate volumes (90 - 100 db). So if you prefer to listen at 75 - 85 db, then YMMV on what networks might be better. With the ALKs, they seem to get better the more you turn the volume knob to the right. Again, ymmv... Mike Quote Link to comment Share on other sites More sharing options...
LoudnClear Posted April 19, 2008 Author Share Posted April 19, 2008 The input is all greatly appreciated guys. I can't say that I don't crank the cornwalls sometimes, not all the time but I like to have that capability in my hip pocket, ie. I wouldn't want to be scared about blowing the tweeters. With that said, the wide, low slope design of the A and ALK give me some concern about out of band power reaching the tweeters. On the other hand, the most starry-eared commenters seemed to like A and ALK the best. pauln's comment in particular struck a chord. That takes me to what I'll likely have as my starting position here: Use either A or ALK with BEC tweeters. I'm also still intrigued with the comments on ALKs website about the benefits of extreme slope band isolation from driver to driver as it relates to clean lifelike imaging. That would be a nice benefit. I wonder if it comes at the cost of open smooth transparent sound that the A's and ALKs are said to have. Regardless, when I listen to the La Scalas, they are not as open and pure as my Cornwall IIs are (yet). The Corns have had quality caps put in the crossovers and been converted to tri-wire input. They sound wonderful and I hope to surpass them with the La Scalas when I get them tuned up. Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 19, 2008 Share Posted April 19, 2008 Most have said that you need to put the juice to the extreme slope networks before they open up and sound their best. That means that you might not like them at lower volumes. The first order networks (6db per octave) does work well at lower volumes and especially with lower power amps. Since the mojority of my listening is at 90 or less (often quite a bit less), the A, AA or equivalent would be would be fine with me. I built the DHA2, another constant impedance type with a gentle slope. Since I also have Bob's tweeters, I'm not worried. Plus, I only have 3.5 watt amps. [Y] My combination just seems to be magic for me, but YMMV. Some loaners would be a good thing, if anyone has them to let you try. Bruce Quote Link to comment Share on other sites More sharing options...
LoudnClear Posted April 19, 2008 Author Share Posted April 19, 2008 Today I'm having a chance to take apart the La Scalas and find out what's going on. First off, this hand drawn layout diagram and the AL schematic in the next post match. I walked throught both. However, MY AL crossovers don't have the dual diode bank that is the second item up from the bottom on the left side of the hand drawing. Its not like they were there and someone removed them, all the other components are evenly spaced, there's not an opening where it could have been removed. I looked over both crossovers for bad solder connections. I only found one and it was on the La Scala with the bad tweeter. The contact was obviously a cold solder joint, but it was somewhat tight. After jiggling the wire a bit it came right out of the capacitor lead it was supposed to be connected to. Looking at what node this was on the circuit, the bad solder joint was on the 2 uF cap that is the third item down from the top on the left side of the drawing. On the right contact, there is a black wire that connects to the positive tweeter output (8). However, that appears to be a phasing trick because screw contact 8 is actually directly connected to amplifier input negative. So on the schematic there are 2 circuits relying on this black wire to dump undesirable signal to ground to protect the tweeter. In the tweeter circut, the 125uH coil and the 0.5mH/2uF combo both use my bad black wire contact to flow to ground. Both of these were either open or intermittently open in my crossover. That coupled with the fact that mine don't have the diodes, means that this tweeter only had two 2uF caps in series between it and the amplifier. That results in a 1 uF cap in series if my memory is correct. Looking at the type A schematic, that has only a 13uF and 2uF in series between the amplifier and tweeter, which comes out to 1.73uF. So I wonder what the difference in crossover freq is between 1.73uF in series and 1 uF in series with a tweeter? The possibility exists that the tweeter died due to old age or some other reason, can't be sure. But since I found this, I'm going to touch up the solder and order something to fix the tweeter or some of Bob's tweeters. I still plan on replacing the crossovers. Type A or ALK? Just a bit more thinking to do and I'll have that determined too. Kimball Quote Link to comment Share on other sites More sharing options...
LoudnClear Posted April 19, 2008 Author Share Posted April 19, 2008 This is the schematic of the above layout drawing. Quote Link to comment Share on other sites More sharing options...
BS Button Posted April 19, 2008 Share Posted April 19, 2008 Should you find yourself wanting to tinker, go with the ALK's. Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 19, 2008 Share Posted April 19, 2008 Should you find yourself wanting to tinker, go with the ALK's. Maybe... Quote Link to comment Share on other sites More sharing options...
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