Cathedral Guitar Posted January 13, 2019 Share Posted January 13, 2019 (edited) First time poster here. I'm upgrading 3x La Scalas from the late 70s, and have many questions for the community. My purpose is to use the speaker in a recording studio setup for playback along with either live drums, guitar, and bass. I love how lifelike the La Scala reproduction is, and jamming along with the records is going to be amazing. One of the LS is total stock with AA, and the other pair is recapped AA, but with blown tweeters. The guy tried a DIY mod by drilling out the tweeter horn and GLUING on an APT-50-2. So right now, one APT 50 is dead, and other one works but unglued and sits loose on top. 1) Is there an adapter to attach the externally threaded APT 50 to the stock Klipsch tweeter horn? I know it may not be worth doing, but I was thinking it would be better than no tweeter, or having a loose driver sitting naked on top of the cab. The stock LS needs recapping, so I bought what I think is a modern AK-4 crossover #116601 (pic attached). 2) I'm confused by the separate inputs for HF / LF on the crossover. Is this to allow bi-amping without an active crossover? Is there a way of telling if this is a LS or KH crossover? Right now I'm using it in a 3-channel in a surround mode on a thrift store Yamaha HTR-5860, and it sounds fantastic, even with just 1.5 working tweeters. Before that I had used a HK 730, which I love on other speakers, but on the LS it was too shouty. Also have various amps and a 1960 Telefunken EL84 tube radio to try. Am thinking of cutting up all or some of these LS and installing 511b horns, and I have already noticed liking the tweeter location much better above the enclosure, as if you are standing up, the stock tweeter height is too low. Lastly, 3) does anyone have a preferred tweeter replacement when comparing the DE120 MAHL vs Crites horn? Thanks in advance for any thoughts. Trying to do this DIY on the low end side of budget. The LS were a little less than $400 each. Stephen Edited January 14, 2019 by Cathedral Guitar 1 Quote Link to comment Share on other sites More sharing options...
Deang Posted January 13, 2019 Share Posted January 13, 2019 I’m having .. chest. pains. 5 Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 14, 2019 Share Posted January 14, 2019 Welcome to the forums... If you already like the sound (other than the messed up tweeters), and would like the tweeter higher, I would suggest using a tweeter and horn that would already work with your crossovers but put them in a baffle to set on top of the cabinets, placed at the rear to time align with the mid driver. The clarity and lack of smearing will be very noticable (unless you are deaf). Below is a pic of my tweeters, apt-150s, on my old pair of LS. The apt-150 is an eminence horn with the apt-50 driver attached. Please note that the newer apt-50 is now made by eminence, where the earlier model was made by a company in Poland. Bob C. says the new one doesn't sound as good. There are other better drivers for a very reasonable cost that are available. Bruce PS I usually moved the lamps when listening but couldn't hear a difference when there or not. 1 Quote Link to comment Share on other sites More sharing options...
DizRotus Posted January 14, 2019 Share Posted January 14, 2019 4 hours ago, Deang said: I’m having .. chest. pains. Look away. Quote Link to comment Share on other sites More sharing options...
DizRotus Posted January 14, 2019 Share Posted January 14, 2019 I will soon have a pair of round magnet K-77/T-35s available. Send a PM if you’re interested. I highly recommend contacting Bob Crites @BEC. Bob is a complete straight shooter and expert. His website: https://critesspeakers.com/ 2 Quote Link to comment Share on other sites More sharing options...
Deang Posted January 14, 2019 Share Posted January 14, 2019 32 minutes ago, DizRotus said: Look away. Indeed. Have fun @BEC Quote Link to comment Share on other sites More sharing options...
billybob Posted January 14, 2019 Share Posted January 14, 2019 The EV T35- is a near contemporary(essentially) with the K-77, imlimited opinion. Both desirable of course, would think...good deal. Listening to my T- 25...alright sound. Quote Link to comment Share on other sites More sharing options...
Dave1290 Posted January 14, 2019 Share Posted January 14, 2019 Smiles, welcome to the forum! Hands Deang a nitro pill... Scrolls... 1 2 Quote Link to comment Share on other sites More sharing options...
billybob Posted January 14, 2019 Share Posted January 14, 2019 After having read your intro would say , have surmised the situation. There certainly are options. First use the Yamaha or another, on the cheap and locate something in the way of a tweeter, matching for both, and allowing for the crossover difference, just do the best you can do. There will be others to chime in and, get what you can from the conversation. Still early yet and not to discount any here so far with any input. Will say, where there is a will...there is... Hope you are not into a sensitive time frame for curing this prob...Welcome to the vast forum...whatever works... Quote Link to comment Share on other sites More sharing options...
Cathedral Guitar Posted January 14, 2019 Author Share Posted January 14, 2019 (edited) Thanks, Y'all: Bruce, I really like what you have done, and want to do something similar, but please let me ask you why you choose the APT-150? Did the original tweeter get blown? I can see that the 150 would not perhaps fit inside the cab. Do you like the sound of the 150? Do you know if the driver has external threads? I'm intrigued with the MAHL, but will go slow and listen to the recommendations. Btw., we just watched the movie Alice in Wonderland, which does inspire you to be bold and do impossible things!! Edited January 14, 2019 by Cathedral Guitar 2 Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 14, 2019 Share Posted January 14, 2019 I just didn't like the k77 and at first had a pair of Bob's CT125 tweets. They were fines, but my older son had bought a pair of the apt150s for a project (same apt-50 as original apt-50 with threads on the inside. Just tried it so I could slide it to the back. It works really well nut the apt-50 has a tad bit lower output. That worked fine for me as I also pulled the mids down about 3db (IIRC). Then, by turning up the overall gaun, the bass is a little more balanced, at least to my ears. To me, the stock mids have always been too hot. This is even more true in a pair of original Heresy. I haven't beard Dave's MAHL but everyone seems to like it and the curves look good. I would get his larger one and still use the baffle though. The passive time aligning is a no brainer for me. Bruce Quote Link to comment Share on other sites More sharing options...
glens Posted January 14, 2019 Share Posted January 14, 2019 2 hours ago, Marvel said: PS I usually moved the lamps when listening but couldn't hear a difference when there or not. That's because all lamps sound the same! 2 2 Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 14, 2019 Share Posted January 14, 2019 I left the lamps in place when I was l Doing some light listening... 2 Quote Link to comment Share on other sites More sharing options...
glens Posted January 14, 2019 Share Posted January 14, 2019 Truth be told, some tube lamps sound different than both others and solid state. Except when you're testing them blind, when they truly do all sound exactly the same. 1 Quote Link to comment Share on other sites More sharing options...
glens Posted January 14, 2019 Share Posted January 14, 2019 Sorry, Cathedral Guitar, "all lamps sound the same" when not enunciated distinctly sounds exactly like a fun ongoing thread elsewhere. I couldn't resist... Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 14, 2019 Share Posted January 14, 2019 Found pics on my phone of the origimal apt-50 amd matching horn. I think the new ones are standard 1 3/8... Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted January 14, 2019 Share Posted January 14, 2019 AK-4 = Klipschorn network, AL-4 = La Scala Network. The -4 networks were designed to work with the newer Klipsch midrange and tweeter drivers. Too many components in the AK-4 I would stick with a real nice version of the AA network for optimum performance. 1 Quote Link to comment Share on other sites More sharing options...
Cathedral Guitar Posted January 14, 2019 Author Share Posted January 14, 2019 Thanks for all the replies. My tweeter driver has external threads, so it will not work with the 150 horn. Is there a horn for it, or an adapter that I can drill out and bolt to the already modified Klipsch tweeter horn? Frzninvt, would you rather have a recent AL-4 or an un-recapped 1977 AA? Those are my current options. Regarding the lamp rolling, I just received the ad below for a brand new tape deck, and was surprised to see that it was not at all the kind of tape deck I was imagining! 1 Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 14, 2019 Share Posted January 14, 2019 You are a luthier? That would be a rabbit hole for me... 🙄 Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 14, 2019 Share Posted January 14, 2019 If yours has external threads then this in new horn for new driver. https://www.parts-express.com/eminence-apt-150s-100x50-1-horn-flare-1-3-8-18-tpi--290-559 I'm getting ready to hop on a plane... I'll check back in... in about 24 hours. 😬 Quote Link to comment Share on other sites More sharing options...
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