Jbruno Posted May 1, 2020 Share Posted May 1, 2020 Lucked into a set of LaScalas yesterday at a ridiculous price. I have a feeling that the tweeters may need updated. What’s the best way to check them? Put my ear up to the tweeter and it sounds rough. Not sure if the mid is covering for it at listening levels 2 Quote Link to comment Share on other sites More sharing options...
Skelt Posted May 1, 2020 Share Posted May 1, 2020 This is how I check tweeters. Hold a tube from a roll of paper towels up to the tweeter to isolate it from the other drivers. You should be able to hear it clearly. 2 1 Quote Link to comment Share on other sites More sharing options...
Peter P. Posted May 1, 2020 Share Posted May 1, 2020 Put a voltmeter across the tweeter connections after disconnecting the wires (Pay attention to which wire connected to which contact on the speaker. It's important.) Set the voltmeter to resistance/ohms. It should measure something close to what's hopefully printed on the back of the magnet i.e., 8 ohms, 6 ohms, something like that. You can also put that same voltmeter, in the AC Volts position, across the tweeter wires. Doesn't matter whether the speaker is connected. Turn up the volume, and the number on the voltmeter should increase. That will tell you the crossover is passing a signal to the speaker. If you perform Skelt's test above, it might be easier to disconnect the midrange driver, to make it easier to hear the tweeter. Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted May 1, 2020 Share Posted May 1, 2020 15 minutes ago, Jbruno said: Lucked into a set of LaScalas yesterday at a ridiculous price. I was wondering who beat me out of them. Congrats. Quote Link to comment Share on other sites More sharing options...
Jbruno Posted May 1, 2020 Author Share Posted May 1, 2020 1 minute ago, Woofers and Tweeters said: I was wondering who beat me out of them. Congrats. Thanks. Still can’t believe it happened.... Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted May 1, 2020 Share Posted May 1, 2020 1 minute ago, Jbruno said: Thanks. Still can’t believe it happened.... She contacted me yesterday to let me know you bought them. I was only moment behind you. Happy for you. Rub some money on them, upgrade the tweeter and update the xovers. What amp are you using? Quote Link to comment Share on other sites More sharing options...
mustang_flht Posted May 1, 2020 Share Posted May 1, 2020 Hi, it may be time to make a nice upgrade with a superb Mahl tweeter in wood or aluminum from @Dave A 2 Quote Link to comment Share on other sites More sharing options...
Jbruno Posted May 1, 2020 Author Share Posted May 1, 2020 1 hour ago, Woofers and Tweeters said: She contacted me yesterday to let me know you bought them. I was only moment behind you. Happy for you. Rub some money on them, upgrade the tweeter and update the xovers. What amp are you using? Super nice lady. Moving her son down to FL with since he was furloughed. At first I thought it was typo, once she confirmed I told her I’d take them. Crossovers still look super clean. Few nicks and the tops could use some TLC. Tweeters themselves just don’t sound crisp, bit of a head cold so not trusting my ears just yet. Currently running them with a Marantz 7008. I’m sure an amp would wonders. Once all this CV BS is over, have to start looking. Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted May 1, 2020 Share Posted May 1, 2020 2 minutes ago, Jbruno said: Super nice lady. Moving her son down to FL with since he was furloughed. At first I thought it was typo, once she confirmed I told her I’d take them. Crossovers still look super clean. Few nicks and the tops could use some TLC. Tweeters themselves just don’t sound crisp, bit of a head cold so not trusting my ears just yet. Currently running them with a Marantz 7008. I’m sure an amp would wonders. Once all this CV BS is over, have to start looking. Can't go on looks, otherwise you would have passed on LaScala and went for the Belle. 😁 If you can, post a picture of the xovers. If they are old and still look good, they still need to be replaced. 35 minutes ago, mustang_flht said: Hi, it may be time to make a nice upgrade with a superb Mahl tweeter in wood or aluminum from @Dave A ^ This ^ I have a pair of Dave's LMAHL that I am using on the MCM1900. They are GREAT tweeters and will bring you a large grin factor. 1 Quote Link to comment Share on other sites More sharing options...
Coytee Posted May 1, 2020 Share Posted May 1, 2020 Horns are honky Quote Link to comment Share on other sites More sharing options...
Alexander Posted May 1, 2020 Share Posted May 1, 2020 You can disconnect just one of the wires (either one) on the tweeter for measuring resistance with a DVM. Also stuffing a towel into the mid horn is another way to help listen to the tweeter by itself Quote Link to comment Share on other sites More sharing options...
Jbruno Posted May 1, 2020 Author Share Posted May 1, 2020 1 minute ago, Alexander said: You can disconnect just one of the wires (either one) on the tweeter for measuring resistance with a DVM. Also stuffing a towel into the mid horn is another way to help listen to the tweeter by itself OK, tried the towel method, was not a good sound. What should resistance be if good? What is a bad number? Quote Link to comment Share on other sites More sharing options...
Alexander Posted May 1, 2020 Share Posted May 1, 2020 10 minutes ago, Jbruno said: OK, tried the towel method, was not a good sound. What should resistance be if good? What is a bad number? Usual they will either be good or open, iirc you should see ~6-8ohms. If one of the tweeters sound OK swap out the two and see if it follows the tweeter or stays with the cabinet. You may need to freshen up or update the crossovers. Quote Link to comment Share on other sites More sharing options...
Panelhead Posted May 1, 2020 Share Posted May 1, 2020 My recommendation is play them for a while. Do not know vintage, or crossover. But recapping is in order. Maybe converting to AA or Al’s cheap crossover. Several listed here build beautiful X-overs with nice parts for upgrades. The tweeters in my new LS II failed the ear in tweeter horn test too. Sounded like both were broken. Scratchy, distorted. Think the mid horn covers this at normal listening distance. Replaced with DaveA horns and B&C DE-10. Yours use the smaller horn. I assume if dirt cheap they are older. But DaveA makes horns for La Scala and La Scala II. Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 1, 2020 Share Posted May 1, 2020 DC resistance for a K-77-M should be close to 7.2 ohms. A tweeter by itself doesn't sound good, or natural. Their power handling is so low, it is unusual for it to fail any other way but open, showing infinite resistance. They are not like woofers that can get hot enough to partly unwind the voice coil and rub the magnet. Check the DCR. If it is normal, look at the crossover. What are the serial numbers? Quote Link to comment Share on other sites More sharing options...
Alexander Posted May 1, 2020 Share Posted May 1, 2020 10 minutes ago, JohnA said: What are the serial numbers? Not sure how it happened but I believe the pics in my previous post belong to the OP 1 Quote Link to comment Share on other sites More sharing options...
Panelhead Posted May 1, 2020 Share Posted May 1, 2020 I have listened to the tweeter in many speakers over the last five decades. The K-77 tweeters failed. The Walnut horns and 120’s pass. What the OP is hearing is close to what I was hearing a week after pulling new ones from the boxes. At longer distances the low output level made it inaudible. But I cannot be happy leaving that alone. Original K-77 is the black horn. Quote Link to comment Share on other sites More sharing options...
Jbruno Posted May 1, 2020 Author Share Posted May 1, 2020 33 minutes ago, JohnA said: DC resistance for a K-77-M should be close to 7.2 ohms. A tweeter by itself doesn't sound good, or natural. Their power handling is so low, it is unusual for it to fail any other way but open, showing infinite resistance. They are not like woofers that can get hot enough to partly unwind the voice coil and rub the magnet. Check the DCR. If it is normal, look at the crossover. What are the serial numbers? One is in pics above, and the other one is the same but ends in 255, if I recall correctly. Not sequential, but I'm fine with that. Quote Link to comment Share on other sites More sharing options...
Jbruno Posted May 1, 2020 Author Share Posted May 1, 2020 45 minutes ago, Alexander said: Not sure how it happened but I believe the pics in my previous post belong to the OP They do! Not sure how you managed that? It also looks like my original post with the pictures has vanished??? Quote Link to comment Share on other sites More sharing options...
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