Dave A Posted January 31, 2016 Share Posted January 31, 2016 Brought home a pair of fiberglassed one piece Industrial La Scalas today. There is a hum from them and I would like to know where to start isolating the problem.(s) The history of these is they came from a sound studio that loaned them out and they were returned with a tweeter diaphragm busted and not working. The guy I bought them from said the wires had been disconnected and he put them back in. He also replaced the tweeter diaphragm with one from Crites. I think I remember reading about improper wire hookups could cause this but would like to find out how you guys delve into fixing and isolating a problem like this. Not sure of the age and the only written serial numbers on the back are 17 and 27. They are AA crossovers which since they have been sealed in are the cleanest ones I have ever seen. As an aside here other than the hum there seems to be better stereo sound separation with these than another pair I have with AA crossovers that are the LSBR type. I am half wondering here with the extra heft and fiberglass on these and the pretty serious aluminum protective strips and angles if the sound quality is going to end up better. I know some of you guys brag on reinforcing La Scalas to improve them and these just may already be there by virtue of their construction as they are built like a tank. Anyway any suggestions? Quote Link to comment Share on other sites More sharing options...
Matthews Posted January 31, 2016 Share Posted January 31, 2016 Don't really have many more suggestions than it sounds like you have not already thought about. I would however really like to see a picture of these La Scala incased in fiberglass Matt ♪ ♫ ♪ Quote Link to comment Share on other sites More sharing options...
Dave A Posted January 31, 2016 Author Share Posted January 31, 2016 OK here are some pictures and further info. There are two tweeter types. The horn driver is the spring type and not the soldered type. The wires were not really in there good so it may have been part of the problem but at 6:00 AM I could not exactly crank these up without some rebellion:) Considering the tweeters I am leaning towards getting a pair from Crites. The crossovers are so clean they look factory new. It is scary how nice they look compared to the other four sets of La Scalas I have gone through now. I presume though that the capacitors should still be replaced. Still need an answer of how to determine the source of the hum though and I hope someone chimes in. Yes I remember reading of speakers not hooked up the same but can't find that article to troubleshoot the problem I have. Help would certainly be appreciated. Quote Link to comment Share on other sites More sharing options...
Matthews Posted January 31, 2016 Share Posted January 31, 2016 Wow, those are cool, Dave - Holy Smokes!!! Those crossovers look amazing... NICE SCORE Quote Link to comment Share on other sites More sharing options...
ricktate Posted January 31, 2016 Share Posted January 31, 2016 (edited) Those crossovers need to be rebuilt. The hum is probably coming from you source....receiver or amp. As far as Crites tweeters go you could use them but if yours are working no need to. How ever you can change the crossover point with Crites tweets and take the load off the mid driver. Crites will have all the stuff you need to rebuild the crossover or you can send them to him. Try hooking up a different source of sound to see if it is the speakers which doubt. You can run those with a boom box cause I have done it. It was even a battery powered boom box...lol Another thing you need to do is loosen all those connections on the crossover and retighten them to make sure there is good contact there. Edited January 31, 2016 by ricktate Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted January 31, 2016 Share Posted January 31, 2016 Speakers don't induce hum your up front electronics do! They just reproduce what is fed into them. It is you amp that is humming most likely from a ground loop issue. Quote Link to comment Share on other sites More sharing options...
Dave A Posted January 31, 2016 Author Share Posted January 31, 2016 I suppose anything can happen. I took my amplifier with me to test the speakers if needed but I doubt highly that a trip in the van hurt them. Yes with the other La Scalas there is not a hint of hum at any level and so I suspect the new ones. I just have not had a chance to play with all the variations yet and it may be a few days before I can. I will update when i have new info. Since the seller said everything had been disconnected when he bought them I had suspected there was a problem there first. I had them on long enough to determine there was a hum but no time to fool around yet. I just thought asking to see if anyone had experienced this issue might give me a heads up on where to start. Thanks for the replies by the way and I will try the suggestions made some time this coming week.. Quote Link to comment Share on other sites More sharing options...
LarryC Posted February 1, 2016 Share Posted February 1, 2016 (edited) As Frzn said, speakers with only passive crossovers don't hum by themselves, and Xovers don't either. It's from something else, probably in the electronics OR a defective interconnect, especially a loose plug. Or your sound source, like a TT, CD, processor, etc. A much rarer source is a strong EMI field near the crossovers, particularly near the coils. Move your speakers around to see if it changes. I'd start with the interconnects, wiggling the wires and jacks at both ends of each I/C. Edited February 1, 2016 by LarryC Quote Link to comment Share on other sites More sharing options...
pzannucci Posted February 1, 2016 Share Posted February 1, 2016 A loose ground could be the problem on the crossover. Swap the crossovers and see what happens. Tighten all the screws on the crossovers as well. I doubt seriously it is a driver. No ground in the crossover. Now with that said, something in the crossover could be be making the amps unhappy but doubtful. The amplifier would likely go into overload if so but possible. If you have never had a speaker as efficient as the La Scala, they will magnify any hiss or hum. I used to have a tube amp that I loved on 90db efficient speakers. When hooked up to Klipschorns, I could never enjoy it because of the hum. 1 Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 2, 2016 Author Share Posted February 2, 2016 (edited) Well I have formed a new criteria for buying speakers now. If I cant turn them way up with lots of bass you have to knock off 600.00 or I go. The guy I bought these from I honestly don't think deceived me as he was running these with a tiny 20 amp unit in his garage. Military vet and super nice. When I got these home I had them up pretty loud but nothing to alarming. So today I crank them way up after switching things around and finding my old speakers were just fine, new ones were not. Out comes Toccata and Fugue in D Minor and some volume and ouch. At the very least the speakers will have to be re-coned. The magnets on these are HUGE. Anyway looks like the deal is not so hot but these are the ones I want. It is amazing to me how good they sounded even with problems and the broken speaker cone was not really apparent to me until a real stress test. I look forward to when they are working right. I believe I have found the hum unless there are other problems to. I cant imagine what they did to blow these up. These will go out in my shop which is the only place I get to turn them up and the idea of fiberglass and industrial look and durability will look nice next to the CNC mill and Lathe Any suggestions as to where to go for reconing or should I just look for new? I definitely want the bigger amp speakers however I have to do it. On the plus side I finally got to see the guts of a La Scala and I wonder what one made out of 1" thick aluminum would sound like? Edited February 2, 2016 by Dave A Quote Link to comment Share on other sites More sharing options...
MookieStl Posted February 2, 2016 Share Posted February 2, 2016 (edited) IMO, I would go with new. The Kappa 15C is $110 shipped at PE. Many here have discussed their preference over the K33. I have used both and find it hard to determine one being better than the other, both are great. The price for new K33's makes the Kappa an easy choice to me as long as you are not worried about keeping it 100% stock. The Kappa's also handle the xtra power you mentioned wanting. Edit: since yours are professional model, you may have the K43 woofer (your hand is in the way in the photo). The Kappa 15C performs as well vs that model which is basically the same as the 33 with higher power handling. Edited February 2, 2016 by MookieStl Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 2, 2016 Author Share Posted February 2, 2016 (edited) It is the K-43. As far as I can tell I am the first one in there. I don't intend to drift far from factory specs on this and I don't intend to ever sell them either. I have no quarrel with the sound as PK designed and no desire to change it. I will have a look at your suggestion. Are the screw centers that same as the K-33/43? Edited February 2, 2016 by Dave A Quote Link to comment Share on other sites More sharing options...
mustang guy Posted February 2, 2016 Share Posted February 2, 2016 The last time I had humming LaScalas I finally figured out that they simply didn't know the lyrics. 1 Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 2, 2016 Author Share Posted February 2, 2016 Well these knew the lyrics but the 10 pack a day raspy voice I could have done without 2 Quote Link to comment Share on other sites More sharing options...
MookieStl Posted February 2, 2016 Share Posted February 2, 2016 It is the K-43. As far as I can tell I am the first one in there. I don't intend to drift far from factory specs on this and I don't intend to ever sell them either. I have no quarrel with the sound as PK designed and no desire to change it. I will have a look at your suggestion. Are the screw centers that same as the K-33/43?Yes, direct drop in, nothing to do but screw in. You wont be deviating from the PK sound at all IMHO. I have used both the Eminence Kappa 15C and the K33 and cannot for the life of me, tell the difference. As I said, both sound great to me. Type Kappa into the search feature in this forum. Many have discussed the pros and cons, mostly pros. I'm just giving you options. Reconing is an option, but I would wonder what abuse these speakers were subject to when this damage occurred. There may be other hidden problems. Going new will eliminate that possibility. Quote Link to comment Share on other sites More sharing options...
Dave A Posted February 2, 2016 Author Share Posted February 2, 2016 Yeah it will be new for sure. I don't know what all these were subject to. Wonder how peoples ear drums were after all that? Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted February 2, 2016 Share Posted February 2, 2016 If you want a bit more low end go with the K-33's vs. the K-43. The K-43 will provide more midrange but at the expense of some low end and the La Scala is already bass shy in the lower octaves. The K-43 is the pro woofer that adds an additional 100W of power handling not really necessary in the home environment. I do use one (K-43) in my center channel since I wanted more detailed midrange out of it. Quote Link to comment Share on other sites More sharing options...
Dave A Posted September 6, 2016 Author Share Posted September 6, 2016 Finally got the woofer repaired. All I can say is that the sound is amazingly better with these AA Industrial La Scalas over the really pristine AA LS-BR's with replaced caps which were the go to set before. Separation of instruments is so defined now and bass may not be as low but I can't tell for sure. Even with the old original AA crossovers in the Industrial's it sounds so superior that I am not touching a thing from here on out. Same recordings and amplifier and two different audio worlds. As I sit here typing this I still have a hard time believing how much better they sound. Good thing they are in my shop for listening pleasure so I don't have to argue about klunky ugly industrial things ruining the inside of the house. Quote Link to comment Share on other sites More sharing options...
Islander Posted September 7, 2016 Share Posted September 7, 2016 Glad to hear your speakers are performing to and beyond your expectations. The extra rigidity imparted by the fiberglass sheathing may well improve the bass response, since less energy will be lost trying to vibrate the bass horn side panels. Although the crossovers look like new, those caps have served for many years and may be past their prime. I'm not suggesting that you dash out and get new caps, though. If you're enjoying the sound, carry on! Once you're well used to your new (to you) speakers, say in a year, you might want to try new caps. When I got my 1974 La Scalas (LS-BB), they sounded okay, but a few months later, when I swapped out the old metal can caps for some new Sonicaps, the improvement in clarity was unmistakable. Also, those old K-77s have their limitations as far as the higher frequencies go. Sometimes their output does not match that well, either. Mine differed from each other by 2-3 dB, enough to mess up the stereo imaging a bit, so I replaced them with Crites CT125 tweeters a few days after installing the Sonicaps. That was to give my ears a bit of time to assess any changes, and to be sure they were improvements, and not just changes. The CT125s did improve the stereo imaging and the clarity, so I see them as money well spent. The two tweeters' output was within half a dB, which was likely where the better imaging came from. Congrats and happy listening! Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 19, 2016 Share Posted September 19, 2016 I had a pair of LaScalas that hummed and I found out the answer was simple. They didn't know the words! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.