New CLS owner from Randburg, South Africa

Hello ML owners,

Coming from decades of exposure to large panel full range ESLs I was naturally lusting for a pair of CLS but the Gods of Finance were not interested. Finally, planets aligned a few weeks ago and a deal too-good-to-pass materialised.

So now, I have a pair of what appears to be the first CLS model ("mk1"), possibly with later model panels - I'll research that a bit more but I would certainly appreciate a pointer to a resource documenting and showing the differences between CLS generations...?

PLUS, part of the deal was a brand new set of replacement panels, in-the-box! Speakers had an unfortunate accident (thus the replacement panels) but I hope to be able to rescue them as-is and use the new panels to build another pair of CLS, shall we modestly call them ... "CLS III" :devil:

My first ESLs were the Acoustat Model-3 (still have them!), followed by Soundlab A2x (still have them too!), followed by Acoustat Spectra 44 (current favourites), and finally a pair of Quad ESL63s with common "pfffzzzssttt" syndrome on one speaker.

Over the years I became quite comfortable with ESL electronics. Fortunately, I had no need to become comfortable with panel repairs in the past (well, haven't touched the 63s yet...) and I hope that fortune follows me with CLSes.

Great to be here!

Mike

Hi that's interesting. How do you compare your Soundlabs, Acoustats, and CLS (I have heard only the latter properly, and a Soundlab A3 in a not well set up mode)

Hi Bonzo,
I'm afraid I can't compare the CLS to the others yet. I was busy fixing one broken frame over the weekend. Cold weather + aliphatic glue, not the ideal combination. I prefer to leave the joins clamped for 24 hrs under these conditions.
I have assembled the other speaker in the meantime and played it a bit today.


As far as the other ESLs;

To me Acoustat Model-3 still wins on all fronts. I would call it the most neutral and analytical of all. It does everything right. Brutally revealing and tonally most convincing of all.

Spectra 44 are tonally a bit "smeared". But, they have a wonderful and uniform overall balance and deliver tangible, ESL-fast low bass in spades.

Quad 63 - I really, really like the sound but in all fairness they are heavy on the midrange and I would say a bit "splashy" (over the top).

I have listened to Quad 2905s on a few precious occasions. Sadly, one does not come across a reliably working pair very often. To me, 2905s sound like the last speakers one should buy. Absolute jaw-dropper. I must have a pair one day, but as I said - finding a reliable pair at affordable price has so far been a mission impossible.

SoundLab A2x are a golden middle of the road I would say. Probably the most engaging. The sound is sexy/pleasant/relaxed. Not convinced about the neutrality but the speakers are so engaging that I just can't maintain the analytical focus - I submit to the joy of listening to music very quickly.

Anxiously looking forward to the completion of the other CLS speaker. If I make it home early enough tomorrow evening we'll know if the other one "behaves" .
Cheers, M

Thanks, good feedback. Much to listen to.

And done. Second speaker fixed. Both charged for an hour, no surprises, everything behaving perfectly. Spent about an hour listening.
Happy days ahead!



I'm keeping the strap-clamps on for another day, just in case.

Good news on the repair, welcome aboard Mike !

Thanks Dave

Gentlemen, since I am brand new in ML sound-space, may I use this opportunity to ask:

How big are the sonic differences between the CLS models (CLS, IIa, IIz and any minor revisions in between) and is there a relatively uniform opinion which model indisputably sounds the best?

Assuming that there are no significant electro-mechanical differences between various generations of CLS panels, I would think that any and all sonic differences would be due to changes made to the interfaces?

The reason for the question is that I have a brand new set of CLS (I) replacement panels that I am planning to frame my way and basically pick an interface design to build either based on the ML CLS interface designs, or perhaps something like Acoustat MK-121 or Soundlab interfaces from the simple 2-way crossover, dual transformer era.

All help and hints would be greatly appreciated.

By the way, I have no issue with custom spec winding brand new audio transformers here. There is a company that I used before for rewinding of some blown ESL transformers and their work was excellent.

Hi Mike

Looking at your panels are you sure they are from the original CLS series? The spar don't appear to be the original or any of the II generations that I have seen. That 's not to say they are not but i have never seen them before.

I'm not an EE so take that into account with my observations. I don't see that you couldn't build an interface of the IIa or IIz configuration and use them with your panels. The sound of your panel will be different then later panels since the horizontal spars have smaller to larger spacing from top to bottom. I would think you will have frequency distribution following that layout. The later panels were mirror image in the center smaller top and bottom increasing in size as they moved to the center. How your panels will sound can only be answered when you hear them or someone that has that specific panel layout and has compared them to other panel/spar layout.

The only comparison I can give you is between IIa and IIz. I owned both and had them setup in the same room at the same time. Using the same equipment on both the IIa had noticeably more bass than the IIz interfaces. My preference was obviously the IIz as I sold the IIa's.

Sorry I don't have more information for you.


Brad

Great stuff Mike. I am a firm believer in restoring or keeping classic panel speakers going. The bang per buck is usually excellent.

To think - one day people will be doing that with CLXs

Brad, your frame-works thread was what brought me to ML Owners; stunning work!
Re. panels - I have seen them on and off the forum - these are apparently the "2nd generation" of the first CLS model. Repeating the "web-wisdom": The very first generation was the one with uniform arc across the panel and only horizontal strips. 2nd gen had a slightly different flat-arc-flat shape to improve rigidity and it adds the vertical stripes.
I believe that these panels are sonically very close to "CLS II" except for, as you noted, different spacing of the stripes which imho should not affect the panel timbre much.
Cap/diode voltage multiplier in my interfaces are set to 4.5KV which was another "2nd gen" mod to eliminate panel arcing.

Jason, thanks - I am nearly a life-long fan of full range ESLs. I swallowed that hook, line & sinker first time I heard Quad 63s back in the very early 80s (@ Harrods of all places!). A pair of 63s awaits their turn at the bench too ...

Thanks for the kind comment. As far as the sonics are concerned, I would imagine when listening to your panel you would clearly hear the higher frequencies higher in the stage/image produced by it. With the curved panels having horizontal dispersion for the most part it would seem unbalanced ( just a guess ) as the sound wave would not travel down to blend with lower frequencies.

You will need to try to find newer pair of panels to know for sure but given that you already have them go for it. You can always change panels later if you run across a newer set.

Good luck let us know how it progresses.

Things are progressing nicely The CLS are in the house!



This is still a temporary location, but 10 times better than the small space where I was busy bringing them back to life and testing initially.

CLS are definitely something else. I have NEVER heard rendition of vocals like this, both male & female. Every time I play something with strongly accentuated vocal - for example, Mark Knopfler "Live Nimes 2010", Melody Gardot, Sade, Nick Cave ... David Sylvian! - the "physical presence" of the vocalist just smacks me in the face. Never ever has anything sounded like this, not even the Quad 2905s (sacrileeegeeee, cried the villagers raising the pitchforks...). Acoustat Model-3 does, but you have to clamp your head in a vice because if you move it by a centimetre (apologies, let say - 1/2"), the image is gone.

Brad, I finally opened the box with spare panels yesterday and had one of those "Oh... my... Gawd!!!" moments. New (as in never opened plastic bags!) panels are CLS-II :rocker: :bowdown:
Needles to say, I cannot be happier. I'll be starting with interfaces soon. I wish I had the winding specs for the transformers that are used in CLS-IIz... anyone...?

If anyone might be wondering; equipment, top down:

- DIY 1950's Garrard 301 (grease bearing) with my own 12" tonearm concoction appropriately named "Sacrilege Mk1" - graphite fishing rod equipped with standard SME knife-edge and using the SME 3009 pivot/bearing. Plinth is made from 4 20mm layers of Latvian birch ply (15 layers in 20mm). Topped-up with 6mm solid African Rosewood and veneered with the same.
- Squeezbox "3" (aka Classic)
- DIY Valve preamp with phono stage, designed by a local guru
- DIY Pass/FirstWatt F5 - 25WPC of minimalistic class-A.

Looks great and I'm sure it sounds that way too

Very nice!

Thanks gents!

Had a few friends visiting today including the new owner and everybody was very impressed. So far the ruling is that these sound better than any of the previous ones (see above). I'm inclined to agree.
This makes me even more anxious to start with "The Last ESL" project using those spare panels...