KT88

Regardless of my sanding problem, perhaps export models were made a little thinner and thus lighter for freight?

I just took a picture of the ceiling. Was the ceiling also sanded?

Randy, If it is true that the sidewalls were 19 mm on the standard LS in 1977 then the stupid carpenter has planed off almost 2mm. see photo of the sidewall. how thick is the motor board of the squaker. Can it be that the carpenter has also planed off? see photo.

👍🥂

Randy, thank you for your very informative post. This puts me on the safe side that a sidewall reinforcement of 2 to 3 mm will be sufficient. While I don't have marine grade multiplex like the 1980 LSI, this reinforcement will be sufficient for my purposes. Likewise, I will reinforce the top plate with about 1 or 2 mm. That was also sanded down a bit and it resonates too much when you knock. As a result, I'll get a Lascala that still looks nice and won't be much too heavy. What is the exact thickness of the original sidewalls on my 1977 standard Lascala in raw birchply? With the info I can use a thickness gauge to see exactly how much the carpenter planed off back then.

In 2006 I have renewed my 1977 Lascala which I bought in 1999 visually. The previous owner had done "color tests" to paint the beautiful raw birch to match his ugly dark reddish brown cabinet. I gave the Lascalas to a carpenter to remove the paint from the test strips. Unfortunately, without asking me, the carpenter had planed off a little bit of the siding on the machine. Not much, but about half a millimeter (0.02 inches). Visually the result was good but I was a bit negatively impressed how much more bad resonance it makes in the upper bass range. Now that I have restored almost everything electrical to original condition in the last two years, I want to reinforce the sidewalls. You have to believe me, I remember very well the sound of my Lascala before it was planed. It was on the one hand without too many resonances and on the other hand it was very lively in sound. A tenor sax, a barritone sax, a cello etc all instruments in the critical range of the Lascala sounded very very lively in the original condition of the speaker. Today, because of this very little planing, the balance is no longer in order. I want to fix this because I love my old Lascala very much. Well, is more and more sidewall reinforcement better and better? I want to avoid that the Lascala sounds clean but dead. I know that the new LS2 and AL5 have very thick walls of MDF. I have not heard them yet. For sure they sound very good. But it's a very different construction with different xover etc. In the case of my old Lascala, my gut feeling is that 3mm sidewall reinforcement might be ok. I want the Lascala to continue to have a lively and breathing sound. E.g. the cello. I sometimes think that the weaknesses of the original old LS regarding a dry bass and in rock music are at the same time the strengths in classical and jazz, when it is allowed to resonate a little in the bass. What do you think? Are 3 mm extra a good decision or should I better just take one mm or do you think I should rein in the bass as much as possible...like with an extra 12 mm? Thanks for your time. PS One more note, I do not want to and will not use braces. The area of the opening of the bass should not be reduced and I do not like it visually on the Lascala.

Very interesting, I have read the Audiokarma thread. I think when it comes to measuring my positive listening impression of the T2A vs 36xx, other measurement criteria could play a role, more involving the overall context in the way the LaScala performed as a whole. So we're talking about things other than just SPL. An SPL change can make a big psychoacoustic effect. But what I hear with the T2A is a qualitative difference that encompasses more than if I, for example, cleanly change only the SPL of the K402 at the DSP on my UJ. Phase shift I'm only a technical layman, but when it comes to whether you can hear phase rotation or not, I mean you can hear it very easily in comparison. That the T2R makes a different phase angle than the 3654 could be shown by my simple mono test (left T2R, right 5436). The sound is no longer coming exactly from the center but a bit out of space. Now the question is, what effect a certain phase rotation in the range of the crossover frequency of the K400 can have compared to the phase rotation of the bass (and the tweeter). Because the bass also has a phase rotation over its frequency response, I assume. So can it be sound-decisive that at e.g. 400Hz the bass horn and the K400 show a "happy" well-matched phase angle? At least I believe that in interaction the phase is not irrelevant...even if it may not be so important when considered in isolation (you only hear the K400 for example). Ringing Honestly, the 3654 makes very unpleasant resonances in the upper frequency range of the K400, making everything sound more washed out and indistinct. And that with the higher SPL of the 36xx by only 3dB reduction. In the other forum someone said that more iron could make more ringing, I don't know if that's true but that's how I heard it with the T3654 before! I read the thread. So it is a confirmation and not self-deception in the sense because I wanted to hear something I read. Balance of bass, mid and high. It seems to me that the bass is fuller, almost like an EQ. My suggestion for measurement criteria: All of the following criteria refer to T2A vs. 3654 - installed in the network and measured at the loudspeaker. SPL/ frequency response over all Frequency response of each of the three drivers bass, mid, high, looking at whether the bass SPL changes when the autoformers are swapped. Phase response of all three drivers individually, especially in the crossover area to the bass. If possible, measure something like this Sawtooth impulse with measuring points from 400 Hz to 6000 Hz Waterfall plot, maybe then you can see the larger ringing of the 3654. Perhaps these measurements let understand more the positive sound impression than if only the autoformers are measured in isolation.

I did no measurements, just used my ears. There was a thread where Autoformers were measured. TBH I believe my ears. On the thread below I lost somehow the plot after a while which does not mean that sensible measurements are not worth it. I also are interested to see measured results with significance as a proof regarding what I here.

Thanks a lot, Mike!

If you happen to have a T2A lying around, trade it for the 3654 in your LaScala just for fun. You are the best test candidate for the T2A because you have been used to the 3654 for so long now. However, based on my listening impressions, I think using polyester caps for the tweeter is even more necessary when paired with the T2A. Polypropylene types could really make the tweeter too loud with the T2A. I'm into day 2 and my first positive impression from yesterday was not a short-changed showstopper just because it's "different". I got a lot more timbre, a great 3D stage and not a single 60's trumpet dissecting my ear.

Thanks for the info. Now that I see your photo I remember the red dotted white cables. The question remains whether it is pure copper stranded wire, which I also assume? Yes, the story with the magnetic mounting screw of the air choke was known to me and I have replaced it with another screw made of non-magnetic material. Now it is so that I no longer have the original air choke for the tweeter and also not the 2.5 mH bass coil. Are the components of the replacement crossover (BC) in any other respect than induction value different from the originals?

Thanks, everything is correct with the original wires. Unfortunately, I no longer have mine since 16 years, hence my question.

BTW I was very curious and suddenly impatient, that's why I took the autoformer to the replica xover. The next step will be that with some leisure I will clean the original board of the Klipsch AA xover and rebuild it with all the parts in new shine. Can anyone tell me which wire of the xover is closest to the original wire? Unfortunately the original wiring no longer exists. The same goes for the wiring of the drivers. What can I take there to get very close to the original?

Who is interested in the core of this post can skip directly to the second paragraph. I have described in other threads how I have restored my 1977 LaScala to near original condition over the last two years. Every measure was an improvement. I have walked the odyssey of wrong ways and I have learned a lot also thanks to this forum. I was naive and for some reason I wanted "change" with the stupid promise of "even more good sound". I bought the 1977 in 1999 and I should have left everything as it was. I am completely serious about that. I was stupid and immature...because in my innermost soul I knew they were as damn good as they were left original. Most of all I remember how smooth, musical non aggressive natural and just right the sound was at the beginning. In 2006 I got the virus of change...but I have to say also triggered by this forum. First I bought air chokes for the bass and the tweeter, but that was no longer such a nice sound. Instead of just re-tooling everything, I ordered ALK Universal Xovers because so many people on the forum raved about them. When I plugged them in I was alienated. I heard the tweeter isolated out and the sound as a whole was no longer organic. This led me to put the boxes away and listened with other boxes first, actually a shame. Well, since 2008 I have UJ, so the old LaScala did not have it easy at first to come back again. Since 2020, I hear the Lascala again and I had the goal to make everything as original as possible. Honestly not primarily just for the sake of reverence, but so that I could have a new starting point as a reference. But what happened: with each step back to the original, the sound got better and better. So I learned very quickly that getting closer to the original was the way to go. I reported it here, first the polyester caps, then (very important!) the change to the absolute exact capacitance values of the caps, believe me, there is an important difference between wrong 13.6 and 2.2 uF and right 13 and 2 uF. Then new original diaphragms for the Atlas KV55A, remagnetize the K77 Alnicos, new sealing of the bottom plate. So I had come a good bit far and I was already pretty satisfied. Of all this, perhaps the most important single measure was the change from sonicaps to the polyester types. Then just recently I happened to find some threads here about the Autoformer. After all the other experiences of significant improvements, I had become very curious. Unfortunately, I no longer have all the parts of the original Klipsch AA crossover after all the changes and also apartment moves. But.....I found my original Autoformers, in the last of many boxes in the basement. On the non-original replica type AA Xover are autoformers with the designation 3654/0909 that I have installed since 2010. (this Xover had gotten the polyester caps two years ago). It was also wired like the original T2A, ground to 0, from 13uF cap to 5 and from 4 to the squaker +. Today I installed my old original T2A. First, only one speaker to compare the sound briefly in mono. That was already very insightful. The 3654 makes the squaker louder and somehow more uneven. In the 1000Hz range piano keys are too much forward. The sound is coarser and more "peasant" compared to the T2A. Listening to both speakers mono does not make an exact center, that means for me that the autoformers make a slightly different phase shift. This is not necessarily a quality criterion in itself. But the interaction with the tweeter and the woofer is much more homogeneous with the T2A. I'm not a technician, but it seems that the phase shifting is better matching using the T2A. The speaker now has improved bass energy, not only because the squaker is a tad more quiet. The bass feels more full bodied in the deeper bass region. The imaging is much better, I hear much more complex sound structures and more reverb in the recordings. In stereo, the positive impression is even stronger. What a great stage! So many layers of sound placement. Better and more natural impulse of piano notes and e.g. snare drum. But it is not the impression of only better individual elements. It is the whole sound experience. For the lack of a better description, the sound lives, breathes and transmits right into the heart. E.g. with old CSN recordings I get goosebumps. Anyone who has such a replacement Xover Type AA should really swap the Autoformer for the real T2A. I'm not kidding. It is such a dramatic yet subtle difference. Belief me. The old LaScala has been given a new lease on life.

I have had good experience combining a tube pre amp with a transistor power amp. Of course, it depends on the individual case. But if the combo is well matched to each other, why not. The "tube sound" is often brought in by the pre amp. I have tried it, e.g. a Mcintosh C22CE with a Quad 306 power amp sounds quite good together. But there are also good solid state pre amps. If I were you, I would first fix the LaScala and listen to it with the amps you have.

Prices are skyrocketing...On hifishark.com, this is currently the most attractive offer for a nice vintage khorn in my view...from first ownership! https://www.ebay.de/itm/Klipschorn-Corner-Horns-for-sale-by-original-owner/235001372531?mkcid=1&mkrid=707-53477-19255-0&campid=5338421008&toolid=10001&customid=ff62eed4-ee84-11ed-b0cf-323565383261&pageci=0746352a-12a7-4811-90ba-ee763d454d09&redirect=mobile

So it is this one? https://www.decware.com/newsite/SE84CDIY.htm

BTW, the most inconspicuous device on the shelf is the black one with the two knobs, on the right middle shelf left below the old Quad pre and tuner. This is the simplest unit Glenn Croft ever built, in the UK. RIP Glenn. I bought it more than 30 years ago in London (no Amazon then). It is a pre amp with a nice phono mm input. The output is weaker than the line input. The gold colored amps on the left middle shelf are Leak Stereo 20. The input sensitivity is very high, 0.15 V for full power. That's why this Croft preamp fits like a marriage made in heaven with the Leak Stereo 20. The Croft is only a cathode follower. No gain but impedance matching, and therefore less voltage in the output than in the input. And for me the proof that it sounds better than passive preamps even if the input voltage in a power amp is sufficient. While I'm telling, at the very bottom left is a Sansui receiver my father bought in 1968. A Sansui 300L. That was my first impression of listening to stereo at all. I had it restored 10 years ago, it's emotion...and still good sound. Speakers were Sansui SP10, full range driver in small cabinets. I still have them and they still work very well.

Yes, Shakey. I bought it around 2000 directly from parts connection, which I think was part of Sonic Frontiers at the time. Relatively rare and unknown in Germany. Very nice amp. Do you know it from listening to it yourself?

Like it looks this moment.

Okay, let's make it as simple as possible. Let's compare the latest recordings. For example, we go to Tidal and Qobus for the new releases of the record industry. It's definitely the same mix and, unlike vintage recordings, we don't have the risk of not knowing if we're listening to the same remastering. For example, from the Rolling Stones there are 20 different remasterings of songs from the 1960s and we do not know if we hear the same. But when I see the new releases in the classical genre, it's the same master. Nobody had time to create another master in one day. By the way, I just noticed a difference in quality that has nothing to do with our topic. On Tidal there are almost only new releases in CD quality and only very few MQA. At Qobus, with very few exceptions, the same recording is in high resolution and only very few are in the poorer CD quality. It seems to be the swan song of the bankrupt MQA company. But as I said, this is not our topic now. So I'll have to search Tidal to see which of the new releases are even in MQA. One of the few new MQA releases on Tidal is Carl Nielsen, The Simponies, Danish National Symphony Orchestra by Deutsche Grammophon. It just came out and is guaranteed to be the same mix. It just sounds better with Qobus in high resolution. Everyone here on the forum can compare it themselves. Tidal MQA sounds sweeter on this recording and maybe a bit softer and more spacious. But the sound of the instruments is a bit falsified. Qobus sounds a bit more sober at first but it has fuller dynamics and more authenticity. In the end, everyone should choose what he likes better.

My modest 2 cents. Let's assume that we are listening to the same mastering, really the same music file. Let's listen through headphones to exclude this whole room and hi-fi discussion. Then I have to say that MQA has technical shortcomings compared to a real FLAC file. I hear it. No philosophy of mix intention etc. can make me know that technically MQA file would be better than a FLAC with high resolution. No matter if this file is received from Qobus or from elsewhere. My original intention of this thread was to communicate that I can hear the data reduction of MQA compared to FLAC. Nothing more, nothing less.

I'm just a technically interested layman, I would guess that especially with Class AB amps the nature of the power supply may have even more impact on the sound than with Class A amps, because the power supply is very dynamically stressed in Class AB depending on the instantaneous power demand? I have a MC275 with a Silicon rectification that I would never make any changes to because I don't want to degrade the value. Besides, it sounds very good as it is. There are people who particularly like the old MC30 monos, which may be due in no small part to the fact that they use a tube rectifier? One thing that I noticed very clearly. I have a Fender Bassman, a replica from 1990. This amp has a very valuable feature. It has a silicon diode rectifier. But this is built into a part that has a tube socket as a connection. Now you can easily, because this Fender Bassman has everything prepared from home, this silicon rectifier against a real GZ34 exchange. I have this amp for 32 years, bought new. The biggest difference sonically is not the swap of tubes but the change from the silicon rectifier insert to a GZ34, what a fantastic feature. It's like a controlled experiment because everything else remains constant. When I play guitar with the silicone insert, it's a linear 1:1 change in volume as I play harder or softer. When I use a GZ34, it creates this more "musical" sound. When the amp is fully turned up, the attack drops for a very small period of time and then comes back up like a "pump". You can use the attack with the pick as a musical effect. Also, everything sounds smoother and rounder, as if the GZ34 were part of the really good guitar sound in rock music. Members with more technical knowledge can perhaps describe what I am experiencing. Of course, this does not have to be a benefit in the hifi area, I do not know.

Like here they do it in Europe.

Looks very nice and I am also a fan of tone control. Pity that only a few manufacturers specify the output impedance, which would predict the compatibility with power amplifiers a bit better.