OldCrow

I don't want to forget- I told Bob that the only way I figured it out was with the help of the forum!

001- Thank you for supplying the final clue! Slowly and gently is an understatement. Snug fit! I measured continuity from each speaker terminal to either side of the diaphragm. However, I measured open across the diaphram. There's a light film on the diaphragm wires that blocks the probe. I razored off a small point. Same condition on both drivers K55X. Called Klipsch for replacements, got 3 speaker supply references, only one, Midwest Spkr, carried them and there was a waiting list. The tech Dave was very knowledgeable and helpful and directed me to Bob Crites. Had a very informative discussion with Bob, particularly my testing and diagnosis. While we were talking he went into the back and got a K55X driver. Sent me pictures and walked me through. He agreed that is likely the problem. DISCLAIMER: I do not hold him to that. Phenomenal phone service! The short version is I can send the old drivers for repair or purchase new drivers. I don't know what forum etiquette is about mentioning prices, but either way it's only a few hundred dollars. Shockingly reasonable! The owner of these speakers inherited a big stack of great equipment. They're leaning towards keeping the speakers now. I would recommend the new ones especially since the difference is only $110. My thanks to all of you who have contributed your knowledge and experience to guide me through this. I was amazed at how many and how fast the responses were.

Update! I went to the owner's home armed with a multimeter. I had watched a youtube entitled What's in the Box? about la scala's. Disconnected tweeter from crossover and measured resistance at 5.9 ohms (2nd tweet is 5.8). Measurement point was the end of the two wires connected to the tweeter that were just removed from the cross over. Tried a test I had read about here using a AA battery. Hold one wire on one end of the battery and quickly brush the other end with the other wire. It should produce a scratchy sound- it did! Same on 2nd tweeter. So far so good. Now the problem. Disconnected and unscrewed the mid range unit. The meter indicates both are open (OL reading). No noise with battery test (note: the discussion for this test was about tweeters. I don't know if it works for mid range). Put things back together. Surprise! Both tweeters working now (loose connections?) as well as woofers (which had always been working). And the sound has cleaned up and unified considerably. Much better than when I first heard them. Now it sounds like just the mid range is missing. So now both mid-range test as open. I read woofers are 4 ohm, mid-range are 16 ohm and tweeters are 8 ohm, but I think the post was talking about Forte speakers. I measured the mid-range right at the driver connectors. Is the OL reading on the mid range a death sentence and the likely cause of the problem? Any other test for them? Am I ready to order new mid range drivers? I read something about replacing just the diaphragm? Thanks to everyone for advice and support.

Babadono, I apologize for being MIA. These aren't my speakers and I hadn't heard from the owner until this morning. She talked to Klipsch support and is going to order new tweeters. The mystery components will remain a mystery. They don't match anything in the La Scala according to the owner. My thanks to all of you who assisted with information and advice. I'll post again if I get an update.

Islander- thanks for verifying the speaker model. Seems if you say La Scala, they could be new, 60 years old, or anywhere in between. You're right, this shouldn't be an age problem, I think something happened to them. Marvel- good point. I hadn't considered Frankenspeakers. The screw heads on the back seem untouched, but I'll definitely have a look at the crossovers. Thanks.

001- thanks for the reply, very informative. Do you by any chance recognize the two items pictured at the top of the post? I'm pretty sure one is a tweeter. Billy Bob thinks the round item might be a speaker diaphragm. Schu identified The dimple in the round item as a phase plug. But I still don't know what the item is or which speaker it's associated with. There's also a possibility that it's unrelated to the speakers entirely and just an odd piece of hardware that her father had.

Schu "what the heck are these?" That's what I'm trying to figure out. In the first post, there are four pictures. The top two are tweeters and the bottom two are the item in question.

Sorry Schu, I missed your source question. As outlined at the top, there were two amps and two preamps. There were XLR and RCA connectors. There were bal/unbalanced and bridged/stereo toggles. There were subwoofer crossover controls on the Parasound preamp. I googled the owner's manuals to ensure all the switch settings were correct. I even brought a Kenwood receiver and another CD player for a minimalist set up. I also drove an hour to a Klipsch showroom to hear what they should sound like. Magnificent! The dealer indicated even with run of the mill equipment, they should sound pretty good. Also, the bookshelf Klipsch sound great with the equipment. So I'm relatively confident it's the speakers.

Billy Bob thinks the item is a speaker diaphragm. Schu identified the dimple as a phase plug. Is it a speaker diaphragm and which driver would it be associated with?

There are top and bottom pictures of the item above. The top has four bolts and a lens like center. The bottom is smooth metal with a dimple in the middle. I have not taken the back off to see the crossover yet. They aren't my speakers and I don't want to weird out the nice couple. I visited once to audition the speakers and once to begin troubleshooting. Audio enthusiasts are quick to help each other out, just like this forum. I've gotten three or four replies in 20 minutes already. Regular folks might just think you're being nosy.

Thanks for quick responses guys. I think we're talking about La Scala II Heritage models. The grills are screwed on from the back. If something did indeed get scorched, the crossover could be damaged as well. But it seems like the father went as far as to purchase some pieces. I'm pretty confident about identifying the tweeters (Panelhead comment). Do either of you recognize the other round object?

This is the longest thread I have ever posted anywhere! It's for a good cause, but I have no experience with La Scalas. Last week I met a young married couple who had recently inherited her father's system. La Scala IIs (logo in upper grill corner), RP 600M II bookshelf speakers, Macintosh MC402, Adcom GFA 575es amps, Parasound Halo P5, Adcom GFP 750 preamps, SVS SB 16 subwoofer, and a Yamaha CD player. She's keeping the Parasound, Adcom amp, and the small speakers. The rest is for sale. I've been an audiophile for 40 years and never seen a stack of equipment like this outside of a showroom! My core system is Polk Audio SDA SRS speakers with Carver M1.5t, Crimson 275 amps, Parasound and 10 Octave preamps. She lived nearby and I wanted to hear the LaScalas for possible purchase. Now comes the problem. They sounded terrible- boomy, underwater bass burying weak mids and highs. I heard a set of K horns in the 70s, but had no real experience with horns. I have read extensively about Klipsch and "their sound," but this was definitely not right. She had a friend help her hook it up. She said it sounded nothing like she remembered. I had hoped it was a simple wiring problem, but the friend had hooked it up correctly. Also, there were XLR connectors, balanced/unbalanced and stereo/bridged toggles, and the Parasound had crossover controls for the subwoofer (which had already sold). I checked the jumpers on the speaker back, and the upper/lower section connection. I tried all combinations of equipment, even brought over a basic Kenwood receiver and another CD player. Always the same. Both speakers sound exactly the same. I took off the jumpers and ran the uppers and lowers alone. Even though the sound is terrible, there is a center image and I can hear stereo imaging. It sounds like all the drivers are firing, it just sounds bad. I can't imagine the same problem in both speakers. I've never had any experience with blown drivers, but that's what was coming to mind. Then she said she also had some parts (see pics). She didn't know what they were for. Two look like tweeters and two I didn't recognize. On this forum, I read a 2018 post by member Panelhead recommending replacement of blown tweeters with B&C DE-120s. Those were the tweeters she had! Great thanks to Panelhead- he supplied my first breadcrumb! Now I'm guessing her father had problems and had ordered some parts. So now we have two tweeters and will try swaptronics. Does anyone recognize the other two round pieces? I watched a YouTube of someone dismantling an AL5 and he unscrewed the mid-range driver. Was there a different type on the IIs? This has become a bug under my skin. I really want to help this couple fix their speakers. I have visited them twice but have not removed the back panel from the speakers. I'm a retired Air Force electrical engineer and no stranger to troubleshooting. I've seen some threads about checking signal path with a multimeter. In closing, does anyone recognize the round device with four screws on it? Also, what would be the next step after swaptronics? Thanks for your time.

I've been jammin' with the M1.5t since it was restored/modded and it sounds like a completely different amplifier! I was snooping around YouTube for reviews and found one by Scott Lowell entitled "Should you buy, refurbish or upgrade vintage Carver audio products?" He discusses in some detail the nature of the process and it's effect on Carver's transfer function t modification. Bob tweaked various components in his amplifiers to null other highly respected amps. In the case of the 1.5, he nulled a Mark Levinson ML2. The restoration/mod uses components that are 40 years ahead of the original. Bob's t mod is gone. It is literally a different amplifier and in my opinion a vastly improved one. The clarity, detail, and impact have increased dramatically. I've used this amplifier exclusively since '85 and have a strong sense of before and after. I had a friend (a strong friend) bring over his Mark Levinson 27.5 100 WPC dual mono amp for a face off. We agreed it was a draw (because he's my friend). Privately, I think the beast whooped'em. Granted, the 1.5 is supposed to be 520 watts now. But our listening levels didn't put a dent in either one of them. He also recommends two Carver repair centers. I used Nelion Audio and can highly recommend them. Usually, the most you can hope for is a successful repair. In this case, I got way more than I had anticipated! Here's the link for a 20 minute video: https://youtu.be/hc1QCDHrDMM?si=QfjwJUObkb1gBvJX

I have the 10 Octave LP1R and Parasound Zpre3 preamps and Carver Crimson 275 and M1.5t amps running Polk Audio SRS1.2TLs. All combinations are ghostly quiet. The LP1 is a powerful preamp, with 9:00 volume setting producing sound levels like 1:00 on other preamps. I've read articles indicating preamps have outputs of 4 to 20 volts max. The LP1 specs are 20 volts. My first preamp was an Adcom GFP1A with all the bells and whistles. I never used tone or balance, and I've cut loose from vinyl, so I went for a minimal preamp. I got the Zpre3 as a backup. No phono, no loudness contour, but balance and tone controls on the remote. I had the M1.5t refurbished and modified recently and it's a big, beautiful beast! The Crimson 275 is a bit more restrained, but has that lovely liquid sound you hear about from tubes. My favorite combination is the LP1 and the M1.5t. The clarity and power create amazing detail and texture. If you don't mind minimalist, I would highly recommend the LP1. I had never realized preamps had different output levels, but there's no question about it. It makes the rest of the system sing! I read a quote from Alan Parsons: Audiophiles don't use their equipment to listen to our music. They use our music to listen to their equipment.

No one's posted for a couple years, but here's my two cents. I bought a 1.5 in '85 and it recently conked out. It was a beast driving Polk Audio SDA 1s and later the big SRSs. I had three concerns - a slight hum through the speakers, a speaker thump at turn off, and NO power switch! I sent it to Nelion Audio, MI for reconditioning and the MKII upgrade which included a power switch. It's better than ever! Detail and texture that I haven't heard before, just spectacular. There's more power, but that was never really an issue. Added new binding posts, an IEC socket, AND a power switch! No hum, no thump, it's a ghost. Serving in the military practically requires owning a great stereo. In my 24 years USAF, I bet I heard close to 100 hi-end systems. Carver owners were almost always happy campers. Bob's a genius and not only misunderstood, but pretty much incomprehensible to us regular types. There's mentioned in a previous post of a technician who couldn't understand what was happening inside and said it's too complicated. No kidding! Specs are all well and fine, but who cares when it sounds magnificent?