AB3CX MIke Posted July 9, 2020 Share Posted July 9, 2020 After owning some Forte IIs, loving them, and then selling them to upgrade to Cornwall 3's, I have finally succumbed to a local sale for a pair of late 70's LaScalas (3N610 and 3N612). These have AA crossovers. All the drivers are good and with only a new Mid-Fi Yamaha solid state driving them, they sound fabulous. The LaScalas are at a vacation house, in a high ceilinged open space in a log cabing type structure. The Cornwalls are on a McIntosh system at home, but in a room a bit small for the speakers to separate widely. The LaScalas sound grand in the larger space. I've read up on some of the crossover updating threads, and felt initially that the caps should be replaced. The new caps are on order, but my anxiety is that the new caps might change the sound in a negative way, since things sound pretty good now. I could always save the old caps, or at least test them on a component analyzer before soldering in the new ones. Sometimes leaving well enough alone is not a bad thing. Thoughts?? Quote Link to comment Share on other sites More sharing options...
consistent Posted July 9, 2020 Share Posted July 9, 2020 If you like what you hear don't change it until something needs changing. Listen to them for a few months then ask the question again. Happy listening 1 Quote Link to comment Share on other sites More sharing options...
gfong Posted July 9, 2020 Share Posted July 9, 2020 I was in the same boat as you and took the plunge and changed the caps. For me it livened up the speakers and added clarity. It did change them a bit but within a couple of listening sessions I was very pleased with the new found clarity which I know was there when they were new. (I owned a pair back in 83 sold them and then bought these 1979 pair used) That is another reason I wanted the refresh done on them. Good luck on your decision. 2 Quote Link to comment Share on other sites More sharing options...
Deang Posted July 10, 2020 Share Posted July 10, 2020 The old caps were lossy to begin with and have probably gotten worse with age. I predict the new caps you bought will sound too bright. I use film and foil capacitors and then drop midrange output 1 or 2dB to bring things back into balance. 1 Quote Link to comment Share on other sites More sharing options...
Panelhead Posted July 10, 2020 Share Posted July 10, 2020 Got to add my 2 cents. The change to new caps will be very apparent once installed. They will be an improvement. A set of DaveA’s horns and B&C DE-120 will bring response up to 20 kHz. To balance the more extended highs, a sub will add to the low end. A true high resolution full range speaker system. 2 Quote Link to comment Share on other sites More sharing options...
OO1 Posted July 10, 2020 Share Posted July 10, 2020 1 hour ago, Deang said: The old caps were lossy to begin with and have probably gotten worse with age. I predict the new caps you bought will sound too bright. I use film and foil capacitors and then drop midrange output 1 or 2dB to bring things back into balance. THANK YOU ---- Quote Link to comment Share on other sites More sharing options...
Islander Posted July 10, 2020 Share Posted July 10, 2020 I bought a pair of 1974 La Scalas back in 2006, when they were just 32 years old. They sounded okay, but when I replaced the caps a few months after I got them, I was very pleased with the improved clarity. Anyway, if you don't like what you hear after listening for a few weeks, you can always switch the old caps back in, but I'd be surprised if you decided to do that. 3 Quote Link to comment Share on other sites More sharing options...
OO1 Posted July 10, 2020 Share Posted July 10, 2020 On 7/8/2020 at 9:30 PM, AB3CX MIke said: After owning some Forte IIs, loving them, and then selling them to upgrade to Cornwall 3's, I have finally succumbed to a local sale for a pair of late 70's LaScalas (3N610 and 3N612). These have AA crossovers. All the drivers are good and with only a new Mid-Fi Yamaha solid state driving them, they sound fabulous. The LaScalas are at a vacation house, in a high ceilinged open space in a log cabing type structure. The Cornwalls are on a McIntosh system at home, but in a room a bit small for the speakers to separate widely. The LaScalas sound grand in the larger space. I've read up on some of the crossover updating threads, and felt initially that the caps should be replaced. The new caps are on order, but my anxiety is that the new caps might change the sound in a negative way, since things sound pretty good now. I could always save the old caps, or at least test them on a component analyzer before soldering in the new ones. Sometimes leaving well enough alone is not a bad thing. Thoughts?? Deang says to do it ----------you are getting the good advice ---- Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 11, 2020 Share Posted July 11, 2020 I've had speakers that went both ways. Putting Holand Musicaps in my La Scalas cleaned up a lot of sounds and did not make them too bright. I had an H700 from 1968 that did not need new caps. If your La Scalas sound big and forward, out in the room, not recessed or distant, the caps were good enough. Quote Link to comment Share on other sites More sharing options...
AB3CX MIke Posted July 14, 2020 Author Share Posted July 14, 2020 I thank all for the input. Over the next few days I am going to do an "experiment". I am going to use a component tester to check my new caps for value and ESR before installing them. I'll swap in the new for old and check the values on the old ones. Of course the subjective or sound test is the one that counts, but I'm curious how the old caps may or may not have held up. Component testers are now very easily purchased and can quickly analyze individual caps or circuits, of course these are static and not dynamic tests under load, but they convey some idea of component quality. Quote Link to comment Share on other sites More sharing options...
AB3CX MIke Posted July 14, 2020 Author Share Posted July 14, 2020 (edited) Here is the result of the capacitor check: ( all caps removed from circuit before checking.) the two high value caps were Sprague 14 ufd 150 VDC. One measures 15.2 ufd with 0 ESR, the other 18 ufd with 0 ESR All four of the 2 mfd caps were CDE rated 200 VDC. They were all pretty much spot on and all four had 0 ESR also on the meter. So none of them were leaky. I decided that since 13 mfd is the correct value per the posted schematic for the crossover high value cap, to put new matched ones in for those two. To my surprise, I did decide the audio improved, notably. So I replaced the rest. My music test for speaker quality is Mozart's Clarinet Concerto in A Major. Having worked in antique radios for years, I had always thought that a cap was a cap, if it was good and on target for value. So my experience set me up to not expect an improvement in sound. I would have to say that the clarinet solos sounded crisper, not as diffuse and the orchestra just better. Maybe having gone to all the trouble we become biased to hear improvement, hard to say, this is not an A/B test clearly. In any case, certainly recapping does not in any way seem to degrade the sound, so I'm now a convert and will recap in future. Some of you experts please look at the pic of the caps I removed and let me know if these were originals, or themselves replacements?? IMHO the soldering looked factory and undisturbed and have seen alot of radio chassis. As far as the discussions about various brands of caps, it should be noted that there are only so many cap factories in the world, so the small volume higher end caps are probably made in someone's larger plant, like many craft beers. Edited July 14, 2020 by AB3CX MIke 1 Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted July 14, 2020 Share Posted July 14, 2020 Not OEM caps Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted July 14, 2020 Share Posted July 14, 2020 8 minutes ago, jimjimbo said: Not OEM caps One mylar, and the other ???? both subject to deterioration, unlike Polypropylene, which hangs in there longer than most here will LIVE! Quote Link to comment Share on other sites More sharing options...
Coytee Posted July 14, 2020 Share Posted July 14, 2020 On 7/10/2020 at 1:46 AM, Islander said: I bought a pair of 1974 La Scalas back in 2006, when they were just 32 years old. They sounded okay, but when I replaced the caps a few months after I got them, I was very pleased with. the improved clarity. Anyway, if you don't like what you hear after listening for a few weeks, you can always switch the old caps back in, but I'd be surprised if you decided to do that. Tell him about your journey to corruption. 1 Quote Link to comment Share on other sites More sharing options...
AB3CX MIke Posted July 14, 2020 Author Share Posted July 14, 2020 One last question...The crossover thread for AA's suggests disconnecting the Zener diodes. Please explain why and what was their function in the first place which is not needed now? Quote Link to comment Share on other sites More sharing options...
EMRR Posted July 15, 2020 Share Posted July 15, 2020 These caps make a more noticeable difference because they are in a very low impedance circuit. Put them in a typical hi-Z circuit, you may not notice any difference, or much less. Should you continue the journey, the biggest obvious improvement for me was the tweeter, I went to the Crites CT-125 from the stock tweeter and found it much more clear and extended, whereas the stock tweeters were sort of 'fizzy/buzzy' and choked sounding in comparison, for lack of a better description. I had several loose examples of the original to compare. The A-55G squawker is also a definite upgrade, the lower distortion makes for a less 'shouty' forward sound, definitely more relaxed but no less detailed, really more detailed. I replaced the 'desirable' solder tab K-55V's, and also had a selection of those to compare. 1 Quote Link to comment Share on other sites More sharing options...
Islander Posted July 15, 2020 Share Posted July 15, 2020 5 hours ago, Coytee said: Tell him about your journey to corruption. Yes, and I should include your part in it. You were the first member to invite me to drop by and sample the sound of your Jubilees. Much appreciated, even if I live three time zones away. And of course, it was your suggestion to Roy that led to the hybrid speaker design that most of us know and love, including me. Yes, Coytee, I had just discovered this marvellous rabbit hole, and there you were, with just the right suggestions to nudge me closer to the edge, until I fell right in! Maybe it should instead be called a wormhole, since I came out far from home, in an initially unexpected but very pleasant-sounding place, which is now my new home. As I listed in a post in another section a week or two ago, it started when I bought a pair of old La Scalas, a speaker I had hoped to have someday, ever since I first saw a pair in 1971. Then the upgrades began. And continued. For over a decade, every few years there was another improvement, clearly better every time. Now, I’ve got a pair of tweeters that are bigger than the speakers they’re sitting on. The look is extreme, but the sound is extremely good. And it’s all your fault! Okay, mostly. Well to be fair, partly would be more accurate. In any case, thanks, man! I really appreciate the tips and suggestions from you and quite a few other valued members. Thanks, Klipsch Forum! Quote Link to comment Share on other sites More sharing options...
Islander Posted July 15, 2020 Share Posted July 15, 2020 57 minutes ago, EMRR said: Should you continue the journey, the biggest obvious improvement for me was the tweeter, I went to the Crites CT-125 from the stock tweeter and found it much more clear and extended, whereas the stock tweeters were sort of 'fizzy/buzzy' and choked sounding in comparison, for lack of a better description. I had several loose examples of the original to compare. I second that. A few days after replacing the caps in my Scalas, I swapped out the old K-77s for a new pair of CT125s, and found them to be much more clear, plus they can operate higher up in the treble range than even new K-77s ever could. Now Bob has CT120 tweeters, which are said to be even better, but I have not heard them myself, so that’s a second-hand recommendation. Not only was the sound improved, the two CT125s were very close in output, within 0.5 dB, while the old K-77s differed from each other by 2-3 dB. I’m guessing at this, but it seems to me that stereo imaging would be more accurate with matched tweeters. The only issue was that the larger dome of the CT125s meant that I had to chisel a 1/4” relief in the lids of the speakers for clearance. Since the lid of the cabinet is 3/4” thick, there’s still plenty of material left. My mid-Seventies speakers were “top-loaders”, meaning the lids were screwed down by about 20 countersunk Phillips screw. With the lids removed, it was much easier to chisel the necessary reliefs, but depending on the dimensions of your speakers, it might not be necessary. The CT125 tweeters are very popular, so many happy La Scala owners have made them fit and been very satisfied with the results. 1 Quote Link to comment Share on other sites More sharing options...
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