First listening impressions after remagnetization of my old K77 alnico tweeter horns.

[KT88]

I have reinstalled my original K77 Alnico. Before I describe the comparison to the K77M and my K77 Alnico of remagnetization (from now on K77) I would like to say that I do not know exactly about the K77M if they have the original diaphragms. I have never opened them. I bought them in April from an ebay dealer. He had butchered a very good condition 1981 Heresy 1 because the parts bring more money. I saw all the photos because I was also interested in the K55V dual phase plug but the price incl. shipping and customs was absolutely unprofitable for me.

So I strongly assume that the K77M have their original diaphragms because the Heresy looked like it had never been opened, really.

My 6 months with the K77M. To put it bluntly I was very disappointed. For this reason my preface about the originality of the diaphragms. The M sounds flat and unfortunately also very metallic. It has more energy than my original K77 before remagnetization. I do not want to talk further about the M. It made the whole speaker sound "flat" and two-dimensional even without soul. The existing volume of the M did nothing to the overall sound of the Lascala. The M did not "marry".

The K77 was already very emotional before the remagnetization...in quiet passages, mainly strings. But overall it sounded metallic and spiky in the negative sense.

Now after the remagnetization I a) do not recognize the K77 and b) the whole Lascala sounds like transformed.
My hope for effect that quiet strings sound so beautiful was completely exceeded.

The issues reported about a K77 are absolutely reduced to a minimum. So the fried bacon hiss in particular. (As described in the other thread I will rework the openings in the motor board. this could also mean a positive effect in this context).

But now the whole Lascala down to the bass sounds much more authoritative with joy making impulse with a grin on my face.

The mids are much more articulate and there is no separation between squaker and tweeter.

You'll just have to take my experience on faith. That's all I can do. It's such a big difference from the K77 M that I'm seriously tempted to put the M back in and record both tweeters in comparison. If it is more than psychological illusion then one must be able to hear the difference in comparison objectively on youtube with headphones.

 

The frequency response of the K77 is now so that they are powerful in their lower frequencies and the highs are again existent that were no longer audible before the remagnetization. but they are very silky and pleasant on the ear. generally a softer slope than the K77M.

 

Overall, the workshop measured a gain of 1.5 db. I asked for it again in writing today and they confirmed it. 
I wanted to have the measurement but they said that was not saved and it was measured in the near range and that is not so meaningful said the store. Anyway...the difference is significant.

I am especially taken by how incredibly powerful impulses of snares etc. in the middle have now become.

The diaphragms were tested (on one of the tweeters) against brand new ones. they did not suffer and were left original. With the K55V it was different. Their diaphragms had become much worse in contrast to new ones I installed.

 

Next i will have my K55V remagnetized but i don't know if i will experience such a wow effect as with the K77 again.

Anyone who has K77 alnico give them a chance before installing something completely different as a tweeter. My K77s have never been abused yet they have lost significant magnetic power over 44 years. Then the same will be true for your K77 because no one is younger than 42 years.

Man am i glad i gave the K77 (and myself) that chance. All in all including shipping within germany it is 56€. A huge step towards the new originality of my Lascalas.

Please believe me, not a single word is an exaggeration. And I have not smoked herbs....

 

[Dave MacKay]

I'd not heard of re-magnetizing before this. 

 

What symptoms would indicate that re-magnetizing is warranted?

Where does one find places to have drivers re-magnetized?

How expwnsive is re-magnetizing (versus, say, buying a new driver)?

 

Thanks.

[KT88]

Dave, please let google translate this website.

 

https://www.lautsprecher-manufaktur.de/index.php/werkstatt/reconing-sp-1327173451

 

It cost me ca. 60€ for two K77 inclusive dismantling and reassemble the voice coils and the lenses by the workshop including both shippings. Somewhere here Randy001 has posted an US workshop who offers a similar job just yesterday.

It is warranted just because this K77 alnico are at least 42 years of age. Because after that period of time they were discontinued. An alnico magnet loses power just by playing over the decades even if the playing is softly because the voice coil built up its own magnetic field which diminishes the power of the permanent alnico magnet during so many years. And I could clearly hear the difference between the old status and the now remagnetized one.

 

A ferrite has not this kind of issue and will perform with equal strength of magnetic power over decades. Only I prefer the sound of alnicos especially in the case of a K77.

[Edgar]

Alnico can also be demagnetized very quickly by overcurrent, or by shock (i.e., if you drop it).

[OO1]

very interesting

[KT88]

Please have a look from 5:50 to 6:10. This is a documentation in German TV about the shop who did my K77. The magnets must be clamped very tightly. Otherwise, they can shoot through the ceiling or through the wall of the house.

 

 

Here you can see what this two guys are doing since 1981. Very enthusiastic.

 

https://youtube.com/user/LspWerkstatt

[Area 51]

14 hours ago, KT88 said:

after the remagnetization

Thanks for your careful telling of the story, KT. The timing couldn't have been better as the subject of the various K77s had just come up in another thread. I'm glad you're happy with the results.

[jjptkd]

14 hours ago, KT88 said:

My 6 months with the K77M. To put it bluntly I was very disappointed. For this reason my preface about the originality of the diaphragms. The M sounds flat and unfortunately also very metallic. It made the whole speaker sound "flat" and two-dimensional even without soul.

 

This has been my experience with these tweeters as well-- Ordered a pair of Crites CT-120 some years ago and never looked back they are such a great tweeter. In fact I started making the DPHL and have the B&C driver in almost all of my speakers now. 

 

It's interesting to read that such a change can occur over time but it makes sense I suppose, again would be curious to see how these compare once completely restored to old worn out versions and to new drivers available today. 

 

 

[DizRotus]

Thank you very much for a very thorough report of your activities and impressions.  

 

As you know, different strokes for different folks.  I first tried Crites CT125 tweeters when @Allan Songer offered a pair on this forum, as he preferred his K77s (unknown whether M or Alnico).  My son also preferred Alnico K77s in his Heresys, so I sold the CT125s to Michael Colter @colterphoto1in a pair of Heresy.

 

I have CT120s in the “Superized” HIPs in my 2 channel system.  I seriously doubt whether these geriatric ears could identify any of the tweeter variants in a blind test, which is not to suggest that others can’t and don’t have legitimate preferences.  My main motivation to move on from K77s was the unavailability of OEM replacement diaphragms.  

 

IMO, the much maligned K77/T35 is a very good tweeter. The 4 Speakerlab SKhorns used in my mobile DJ business in the mid-70s used T35s.  Replacing a blown voice coil was easy enough.  A call to Electro Voice on  a Monday would have an OEM diaphragm, along with an invoice for less than $20, at my door by Friday.  I’d then mail a check to EV at 600 Cecil Street,  Buchanan, MI.  I miss those days, but time marches on.

[ClaudeJ1]

18 hours ago, KT88 said:

Next i will have my K55V remagnetized but i don't know if i will experience such a wow effect as with the K77 again.

Anyone who has K77 alnico give them a chance before installing something completely different as a tweeter. My K77s have never been abused yet they have lost significant magnetic power over 44 years. Then the same will be true for your K77 because no one is younger than 42 years.

Man am i glad i gave the K77 (and myself) that chance. All in all including shipping within germany it is 56€. A huge step towards the new originality of my Lascalas.

Please believe me, not a single word is an exaggeration. And I have not smoked herbs....

BLEH! (is that the sound of puking?)

 

Reviving 60 year old magnets and technology, even though improved, will NEVER outperform a modern horn tweeter. Why do you think Klipsch Engineering has finally replaced the K77's in their Heritage line? I think they should have done it 15 years ago (I had JBL 2404's on top of my Klipshorns back then).

 

Why do you think I'm such a fan of B&C tweeters with DaveA Tractrix horns? Hundreds of listeners and all of my hundreds of measurements and curves suggest further improvements can be had. If you heard THAT instead of dinkin' around with old technology, you would never go back.

 

But I do like tube amps, I admit. I just don't want to fuss with them as space heaters that wear out too fast.

[ClaudeJ1]

1 hour ago, DizRotus said:

IMO, the much maligned K77/T35 is a very good tweeter. The Speakerlab SKhorns used in my mobile DJ business in the mid-70s used T35s.  Replacing a blown voice coil was easy enough.  A call to Electro Voice on  a Monday would have an OEM diaphragm, along with an invoice for less than $20, at my door by Friday.  I’d then mail a check to EV at 600 Cecil Street,  Buchanan, MI.  I miss those days, but time marches on.

Time marches on for our hearing as well. No excuses for those who refuse to modernize the high end when it's easy to do and is affordable in these inflated times.

[ClaudeJ1]

3 hours ago, jjptkd said:

This has been my experience with these tweeters as well-- Ordered a pair of Crites CT-120 some years ago and never looked back they are such a great tweeter. In fact I started making the DPHL and have the B&C driver in almost all of my speakers now. 

 

It's interesting to read that such a change can occur over time but it makes sense I suppose, again would be curious to see how these compare once completely restored to old worn out versions and to new drivers available today. 

 

 

I had CT-125's. They were pretty flat and worked well in a Heresy as a drop in. But when I put them in LaScalas, I had to drop the K55/K400 by another 3 db and cut the Cap value in half to compensate. Did this by ear, long before I became such a Curving Freak as I am now. 20 years goes by fast in this hobby.

[jason str]

47 minutes ago, ClaudeJ1 said:

I had CT-125's. They were pretty flat and worked well in a Heresy as a drop in. But when I put them in LaScalas, I had to drop the K55/K400 by another 3 db and cut the Cap value in half to compensate. Did this by ear, long before I became such a Curving Freak as I am now. 20 years goes by fast in this hobby.

Dropped mine 2. Besides the poor fit and extra work the 125's are decent to my ears and measurements.

[KT88]

On 11/9/2021 at 4:22 PM, ClaudeJ1 said:

BLEH! (is that the sound of puking?)

 

Reviving 60 year old magnets and technology, even though improved, will NEVER outperform a modern horn tweeter. Why do you think Klipsch Engineering has finally replaced the K77's in their Heritage line? I think they should have done it 15 years ago (I had JBL 2404's on top of my Klipshorns back then).

 

Why do you think I'm such a fan of B&C tweeters with DaveA Tractrix horns? Hundreds of listeners and all of my hundreds of measurements and curves suggest further improvements can be had. If you heard THAT instead of dinkin' around with old technology, you would never go back.

 

But I do like tube amps, I admit. I just don't want to fuss with them as space heaters that wear out too fast.

It's all a question of attitude and what you want to achieve. For me it's the fun of the original product. I have modern speakers as you know, since 2008 (which is still relatively modern) Underground Jubilees (now they finally got an official name:) with TAD 4002, K69 Yamaha DSP, various power amps, and if I like it in between, sometimes in passive circuit with Faital HF200 and the crossover of Bob in the high range and Roy's design in the bass range, which Bob had built for me 8 years ago. And there any further innovation is welcome to me. I would be the first to try and install Roy's new additional phase plug immediately. I am open to any driver and DSP innovation. And it's a very different sound experience. But here comes something not everyone may accept. There is not just "one best" sound for me.

 

Sorry, I love how the sound of the old Lascala increases with the restored but original parts for half a year time after time. I'm going slow and not renewing everything at once. Next up is magnetizing the K55V. After that, the woofers are the task because 15 years ago I used a filler to close the shrunken felt quarters which was a mistake because the filler gets very hard.

 

And I'll tell you something: I like some music better on the old Lascala than on the modern speakers. Donald Byrd or Clifford Brown for example, or a lot of rock and funk music from the 70s. The Lascala may have a cool but own "sound". I optimize it in this direction. My Lascala do not come under the torture of an objectivity compulsion.

 

What is to say against it when I enjoy that I have achieved a significant improvement for the K77. I sit there listening to music and I am not only pleased but even a bit moved. I'm tinkering with a time machine. I was 18 years old in 1977 when my Lascala were built, which I have had since 1999, although little used in the last 12 years, they have been revived since this spring. And I was 18 years old when I listened first and overwhelmed to a Lascala…in San Francisco where I was with my father. This are very personal rememberings…“This“ sound.

 

The Lascalas have won by a long shot the decision of which larger speaker has to go due to space constraints. Because I no longer have a separate office which was my hifi storage facility since I can work from home for the remaining years.

Both bigger speakers I have compared intensively over the past year. It remains the Lascala and it goes my Tannoy Canterbury 15“ from 1993.

Claude I respect your style and your choices. You can optimize everything but I want to achieve the original authenticity as when new. But to be clear...I am not a masochist who suffers from the sound of his K77 Alnico and who feels the compulsion to put originality before listening pleasure. No. It IS listening pleasure as it is now. I like the improvement of originality.

 

I do not want to proselytize anyone with my bold sentence you quote. I would like to invite all those who still have a K77 Alnico to give it a chance. It is a damn good tweeter because it fits damn well with the whole speaker and underlines the character that this damn good speaker has.

My wife and I enjoy a 1970 Alfa Romeo Giulia 1600 super. How dumb would I have to be to lower this car and put oversize tires on it. It will never go as fast and safe as a modern sports car. But the feeling of speed in a sharp turn at 55 miles is emotionally quite different from the same curve in a modern car with all the digital helpers. I'm happy when I catch the rear of the Giulia with its narrow tires just as I'm happy when the Lascala with its K77 catches my ears.

Claude let's respect each other and please no pseudo-scientific discussion about modernity subservience. Everything in its time and place. No one here in the forum must think you or me want to seduce the participants to something.

[ClaudeJ1]

10 minutes ago, KT88 said:

Claude let's respect each other and please no pseudo-scientific discussion about modernity subservience. Everything in its time and place. No one here in the forum must think you or me want to seduce the participants to something.

I actually bought my first LaScala (brand new) as a center for my Khorns using PWK's resistor box in 1977 which I still have. I just put a Potentiometer in the resultant center channel to be able to adjust it for my rooms. I sold the LS to HPower about 13 years ago, so it's somewhere in Canada by now.

 

You never mentioned the COST of re-magnetizing, but I guess it's in the same ballpark as getting your capacitors replaced.

 

There's nothing wrong with what you are doing as an improvement, so I guess from the standpoint you expanded upon, it's all good.

 

This is American and everyone has a right to their own Ridiculous Opinions, including you and I. LOL.

 

PS: It's Scientific, no Pseudo about it. That is reserved for the Pre Amp of the month club.

[KT88]

Oh I mentioned the costs above, 60 € including shipping both ways. I am glad that you see it this way as stated above. Ok, no pseudo science:) Peace to us all.

And as you mentioned we all can chose different approaches which makes this fantastic forum so colourful.

[billybob]

Glad the process worked out for you. ☕