ClSII to CLSIIA crossover

[legarem]

Hello
I have all the instructions to do this task but before doing it I want to know if someone has done this mod.
In fact, about sound, is it really better . What will I hear different from CLS!! to CLSIIA mod ?

I could ask the same question from CLSIIA to CLSIIZ crossover but I read that the goal of the CLSIIZ crossover is to have better load for amplifiers but the sound of CLSII or CLS!IA is better than the CLSIIZ.

Thanks

 

[Brad225]

Hi legarem. I can't say what the mod will sound like, since I didn't perform the operation. Using better caps and resistors will definitely improve the sound.
My EE friend repaired my interfaces and changed the dale resistors along with changing everything to point to point wiring. He said that the circuit board was inferior to the P to P and he was correct.
The other thing he found was that many of the diodes bad solder joints and should be repaired.

I can only speak to the difference as originalIy built as owned the II, IIA and IIZ.
The IIA had more bass than either of the other two. As you said the IIZ is easier on the amps than the others.

Assuming you have an amp that can properly drive the IIAs and you like the bass that is possibly what you might prefer.
I ran them with both Aragon 2004 and ARC Classic 120 amps. I preferred the 120's as they had a much more detailed sound.
You may find a different out come. Good luck.

 

[legarem]

Thanks for your reply
Yes I thought upgrading caps and resistors . I'm not a fan of Solen caps and there's many in the crossover.
Before doing Mods I would really like to have someone who has done the CLSII mod to IIA tell me if the IIA is really better.
As for the bass, I use a Descent I sub under 60hz with no high pass on the CLS. My amp is an old Classe DR15 refurbished. This beast can drive easily tough loads with finesse.
I bought a BAT VK3IX SE tube preamp last week to replace my transistor preamp, This is a GREAT move.

 

[Brad225]

I can assure you that even if you only upgrade the parts in the II and point to point wire it will be a noticeable improvement.

 

[Rehan Azim Hashmi]

Hello
I have all the instructions to do this task but before doing it I want to know if someone has done this mod.
In fact, about sound, is it really better . What will I hear different from CLS!! to CLSIIA mod ?

I could ask the same question from CLSIIA to CLSIIZ crossover but I read that the goal of the CLSIIZ crossover is to have better load for amplifiers but the sound of CLSII or CLS!IA is better than the CLSIIZ.

Thanks

If I recall correctly, I read a long time ago that CLSIIa panel and electronics are exactly same as CLSII. Only difference is in electronics. Namely, addition of a very small inexpensive cable connection in the electronic circuit designed to improve the load presented to the amplifier.

If your existing amp can easily drive the 0.6 ohm tough load you will i assume not hear much difference in sonics after modification to easier load of CLSIIa.

If you have attached to CLSII a amp that struggles to provide high frequency air and clips at average to moderate volume level, then this amp performance will improve after modification to CLSIIa. Improvement in high frequency air and not clip at moderate to high volume level.

I have not listened to CLS models other than the original CLS. Based on what i have read, original CLS, easy load, live midrange or presence in midrange and comparatively weak bass response. CLSII and CLSIIa reduced midrange presence, improved bass performance and in comparison, toughest load. CLS2z reacquire live midrange, easy load though not as easy as original CLS and comparable to CLS2 bass performance. CLS II power draw is largest followed by CLSIIz and last or least in this regard is original CLS.

 

[legarem]

Finally I will buy teflon boards and do CLIIZ point to point crossover.
I'll probably separate the two transformer primary wiring to do bi wiring.

 

[Leporello]

I need to pick a nit: CLS series may have dual step-ups for better matching to the load, and passive components for frequency response shaping (as well as the staggered panel sections for mechanical frequency response shaping) but it is not a "crossover". It all feeds the same two terminals of the panel--for beautiful seamless crossoverless coherence that only the CLS can deliver (even the CLX has a separate bass panel).

I heard the same story about the CLS IIz--probably on this forum: easier load on the amp but sounding not as good. Having never made a side by side comparison, I can't comment on whether this is true. Once at a show I talked to Dennis about sending my interfaces in for a IIZ mod. No prices were mentioned, it was just put out there as an option. At the time, My Cambridge Audio Azure 840 power amp--an excellent amp under most circumstances--was often refusing to power up unless I disconnected the speakers first, due to the short circuit protection (the d.c. impedance of the CLS II's is also brutal). I ended up going through a series of alternative amps, ending with--for the foreseeable future--a pair of Parasound JC-1 monoblocks. I am happy to have gone that route instead of mucking with the CLS II interfaces.

 

[Brad225]

The interfaces are old enough that "mucking" with them, even if only replacing parts will be an improvement.

 

[legarem]

In the CLSIIZ, there's not so many parts to change so I will surely try it. Building something point to point wiring 'on the air' would be simple and fast. If it is better, as stated, I'll use a teflon board to do it permanently. This is not for having an easier load for the amp. It is just a question about sound quality. The amp I have is an old Classe DR-15 which was often recommended to drive Apogees ribbon speakers which have a tougher load than the CLSII. This amp don't work hard with the CLSII.

 

[Brad225]

My EE used the original board and just didn't use the traces on them.
I will see if I can find the pics I took of his work.

I think the Dale Resistors were the most expensive part of the change.

 

[Brad225]

legarem, here is a link to the thread here in the Forums about the repair. Well the system won't post the link.

It is:
{URL unfurl="true"]https://martinloganowners.com/thread/clss-bite-the-dust.15431/#post-164325 {/URL}

I don't know how many diodes like the ones under the plastic shield on the left there are on the CLS model.
As I said previously said, a number of them had bad solder joints and should be addressed.



https://www.martinloganowners.com/threads/clss-bite-the-dust.15431/#post-164325


Finished Pic