Klipsch original alternative to K77 Alnico tweeter

[KT88]

I may not have searched the forum well enough but I have not found anything that answers my question.

My concern. I reactivated my 1977 LaScala after many years and wrote something about it here the other day. My thread about the matching capacitors for example. 
Everything I say now is my own subjective opinion and I would like to emphasise that I do not want to criticise any supplier. It is my very personal choice of components that is at stake here.
In the end, after some excursions like 16 years ago ALK universal Network or e.g. CT125 Tweeter, everything is very original again, with AA crossover, new capacitors and the original K77 Alnico Tweeters.

Unfortunately, these tweeters are an extremely ambivalent matter. On the positive side, the K77 is the only one in my view that reproduces the impulse most closely, that articulates vocals most homogeneously together with the Squaker and that reproduces an acoustic guitar string in such a way that it sounds natural.

But there are also less satisfying aspects. In its original state, my 1977 Lascala sounds very good when you sit right in the hotspot. Also, the three-dimensional depth gradation is very good and, for me, rich in experience.
I could live with the fact that the K77s don't go very high in the frequencies.
But what is a problem is that off-axis the speakers sound completely closed. It's just obviously the disadvantage of the original vintage style. In addition, off-axis there is this sound of frying bacon, this hissing that can spoil all the fun.

Your recommendation would be very valuable to me What can I do. I don't want to improve it in a way that I get other disadvantages.

To cut a long story short, I want a Klipsch Tweeter and not a third party solution.
First things first.
What is the improvement if I leave the tweeter as it is but I would have it flush with the baffle? Is the mounting from behind the board the cause of the hiss? Or is it the old phase plug?
Should I buy a K77D like this, i.e. one that closes off at the front and is a newer version...with a ceramic magnet? (I always thought I loved Alnico).

I heard a 1996 Lascala at a friend's house some time ago. It had K77M classically mounted from the rear, I don't know which Xover. But it didn't have that hiss in my memory.

Or should I just buy a new diaphragm?

 

Can I theoretically use a new K771? 

I am very sure that the K771 was designed in such a way that it harmonises with the K400/401. The aim was to get the best out of Lascala and Khorn without changing the K401. That is Roy's ambition. It is the true heritage of PWK and that is why I am very sure that the K771 was designed with that in mind. It would certainly have been easier to use a new midrange horn. But the K400/401 has very fantastic qualities in my experience. It was developed by PWK for the Atlas driver and I love the sound.
Three questions.
Is it possible to buy the K771 as a single part from Klipsch?
Does the K771 fit mechanically into the vintage Lascala cabinet?
Could I run it with the AA crossover...even if I didn't use its ability to play well above 4500 Hz? Or would I have to use a modern contemporary crossover?
After all, the K400/401 with the K55V is the reassuring constant in all considerations, it's the same...then and now.

Or should I leave everything as it is and buy another modern Lascala?

I hope it was not too much text and that some of you understand what my goal is.

 

 

 

 

[billybob]

EV T-35?

[OO1]

On 5/22/2021 at 8:26 PM, KT88 said:

Is it possible to buy the K771 as a single part from Klipsch?

sure

[pbphoto]

10 hours ago, KT88 said:

But what is a problem is that off-axis the speakers sound completely closed. It's just obviously the disadvantage of the original vintage style. In addition, off-axis there is this sound of frying bacon, this hissing that can spoil all the fun.

How far off axis does the problem start?  Did this happen when you were running the CT125's ?

[KT88]

12 minutes ago, pbphoto said:

How far off axis does the problem start?  Did this happen when you were running the CT125's ?

In my experience the CT125 is not so good integrated when I listen on-axis which is the most important listening position to me.. It may be liked very much by others and it is a high quality item but the „Klipsch sound“ is somewhat gone in my view, especially the homogenous attack in the whole freq. band. I have angled the speakers so that I can see the inside walls a hand wide from my listening place. This offers a 3D stage for my listening. But when I walk in the room the Lascala sounds „shot in“. I can imagine that the tractrix K771 solves this issue. Or may be a K77D as well?

[Marvel]

Many, many folks on here have complained of the midrange being too hot on the La Scala... like for the last 20 years. I would have to look and the specs again, but I think the CT125 has a slightly lower output than the K77, although smoother and more extended.

 

I made mine '89 LS a non-Klipsch product by using a different crossover, where I could more easily drop the mids a few db, and added the CT125 from Bob Crites (may he RIP).

 

This made the overall balance seem better to my ears. I never did any testing to see what the response was, but I could listen for hours and not be fatigued. Ok, no longer Klipsch voiced...

 

You may find pulling the mids back a little would work for you, too. It's possible it isn't the tweeter that's your problem, but the mid.

[Frzninvt]

I was not a fan of the CT-125's in my La Scala's I went back to the K-77M's and have left them that way ever since.  I would pick up a set with and put in new diaphrams to make them new again and call it done.

 

[KT88]

7 minutes ago, Frzninvt said:

I was not a fan of the CT-125's in my La Scala's I went back to the K-77M's and have left them that way ever since.  I would pick up a set with and put in new diaphrams to make them new again and call it done.

 

Thank you for your post. As I wrote I listened very extensively to a then new Lascala at a friend's house in about 1996. It had K77M and it didn't sound as noticeably like ham sizzle as my old Alnico K77s do these days.

What would be your advice, buying new diaphragms for my Alnicos or better directly swap for K77M and collect the Alnico? I love Alnico magnets but the K77M have more magnetic force and therefore a higher frequency response and therefore a bit less hiss?

This solution would please me very much because my speaker would remain largely original...

[Marvel]

1 hour ago, KT88 said:

This solution would please me very much because my speaker would remain largely original...

 

I know this is your goal, but our aural memories can be difficult to chase and pin down. I wish you success.

[Deang]

If you want to maintain the aesthetic of your loudspeaker with improved performance, you should go to the K-77-M, CT-120, or the SMAHL.

 

https://www.ebay.com/itm/324294400148

 

All of the K-77 variants sound like a Kazoo when pushed.

[KT88]

Marvel, at first, thanks for your posts, I know, memory can be deceiving. At the moment I also have the impression that I should wait a bit, because since only 10 days I have the new capacitors in the Xover. And whether it's my psychoacoustical adjustment or actually a break-in process of the capacitors, or both...the sound is still changing a bit every day at the moment. But overall, I think the Alnico tweeter is playing not high enough in the frequencies because with the exception of the slight hiss the sound has become very natural with the new Polyester caps but the cut off of the Alnico  gives less a 3D presentation in comparison to the CT125. But I would more sacrifice 3D than impulse and seamless presentation of the K77 series.

If the K400 stands out a bit, maybe a K77M would perhaps be a good addition.  It's fun to finetune so nicely. First and foremost, I'm very pleased that I'm going back to originality based on the AA takeover points.

 

 

 

[KT88]

14 minutes ago, Deang said:

If you want to maintain the aesthetic of your loudspeaker with improved performance, you should go to the K-77-M, CT-120, or the SMAHL.

 

https://www.ebay.com/itm/324294400148

 

All of the K-77 variants sound like a Kazoo when pushed.

Okay, theoretically the CT120 would also be an option. Since I have the CT125 I only need to buy the B&C DE120 drivers, over here for about 90€ a piece without customs because they come from Italy. To my knowledge, the Crites horn is the same for CT 125 and CT120.

[KT88]

BTW would the magnet of the DE120 fit into the Lascala box when mounted on the CT horn or is it in same way slightly too big in diameter like the CT125?

[OO1]

3 hours ago, KT88 said:

 better directly swap for K77M

best option -

[geoff.]

@KT88, I have CT-120s and CT-125s. 

 

The driver mounts completely differently to each respective lens.

 

There USED to be an adapter available form Eminence, but ironically only a few weeks ago I was told by the one source I could find that it was discontinued by the supplier.

 

I’m positive a crafty individual could super glue a carefully cut flange to the CT-125 lens but now what to do with APT-50?

 

I also have the SMAHL lens on the DE-120 in my LS and it is everything others say it is, but I realize just the shipping alone would be prohibitive where you live as I am also outside of the U.S.

 

The hiss issue you describe has me puzzled though. Usually the hiss disappears when the crossover capacitors are replaced. Maybe now you are hearing the noise floor of your system components?

 

 

[Marvel]

30 minutes ago, KT88 said:

BTW would the magnet of the DE120 fit into the Lascala box when mounted on the CT horn or is it in same way slightly too big in diameter like the CT125?

 

The CT125s fit fine in my LS. There is a 1.1 millimeter diameter difference between the two drivers, the B&C being larger. It may fit, it may not. Since the LS weren't being made with CNC, there is some variation in the builds.

[OO1]

On 5/23/2021 at 12:32 PM, KT88 said:

 To my knowledge, the Crites horn is the same for CT 125 and CT120.

--the CT125 screws on the APT50  threads -- the CT120  is bolted to the tweeter   -2 different parts

 

[OO1]

5 minutes ago, geoff. said:

 

There USED to be an adapter available form Eminence, but ironically only a few weeks ago I was told by the one source I could find that it was discontinued by the supplier.

do you have a picture of the adapter --I am trying to visualize the part -

[KT88]

It's not the background noise that I mean by "hiss", geoff.
It is this added metallic tone when I hear cymbals for example. Years ago Al Klappenberger explained it here in the forum very vividly. The K77 sounds like Sssssssssss, a softer tweeter like Fffffffffffff. Of course that's not the only reason to choose a tweeter respectively what this thread is about.

Many thanks to all for the explanation on the fit of the tweeter horns and magnet sizes.

My gut feeling is that I will try the K77M first before trying other designs. Such parts can be sold again quite well if it does not like.

 

I am of course very interested in this topic but I will postpone the tweeter decision a bit because I noticed today that my KT88s are very worn. The tubes have been running a lot since last year in March, partly because of Covid and all the time more I spend at home. I connected the amp today to conventional speakers with much lower efficiency. There I hear quite clearly that they sound thinner and shriller than normal, the meat is missing, especially in the lower mids, in the bass section anyway. I did not notice this so explicitly with the Lascala because you need so little amplifier power. But still, the sound of the amp is not as powerful and silky, likewise with the Lascalas. Therefore, before I modify anything on the tweeters the amplifier must be back in full juice. I have ordered new KT88 (the small tubes are fine and relatively new).  Otherwise I'm in the fog and have no reference when judging the tweeters.

 

 

[Marvel]

Did Bob make a new horn or does it still use the mounting style that Tonsil (Poland) still uses on the APT-50?

 

Eminence changed the machining to use the more standard 1 3/8 threads.

 

That complicates it a bit.

 

@KT88

 

Did you import from Bob to get you CT-125? You could uncrew it to see the difference. I don't think there is an adapter from the older Tonsil threading to mate a bolt on driver.