I was a Martin Logan dealer for many years and currently use a pair of CLSIIA’s as one of my reference speakers.
When I was a dealer, I always had a pair of the older model on demo when the new model came out. I was able to A/B them side by side.
The CLS I (there was never a CLSIA. Actually, it was just the CLS). These had a different pattern to the spars inside the panel and were easy to tell that they were the CLS versus the later model. The CLS would drop down to around .6ohms and was an amp eater.
The CLSII was designed to be a little easier on amps. These would drop down to around .8-.9ohms.
The CLSIIA was developed very shortly after the CLSII came out and was field retrofittable. It was a pretty easy mod to do and opened the speaker up quite a bit and smoothed it out over the CLSII, but still was pretty hard on amps.
The CLSIIZ was developed to be even easier on amps. These drop down to around 1.2ohms and did indeed help with the amp situation.
When I was able to hear them side by side through their evolution period, I liked the CLSIIA the best. Many owners will say the CLSIIZ was the best, but I’m not sure that everyone had the chance to hear them side by side. This is just my opinion, but Gayle Sanders once told me that he thought they had lost some of the "magic" & "sparkle" when they went from the IIA to the IIZ, but it had to be done to try to address the amp problem.
Martin Logan has a serial number decoder to help you know which version you have and to tell how old the electronics and panels are. I have a pdf copy if you want it.
The ML panels last around 12-15 years before they need replacement. Unfortunately, ML has really raised the prices of replacement panels. I replaced mine a few years ago for $890 plus shipping. They are now $2700 plus shipping.
There is a guy named Russ Knotts that will rebuild a pair for around $600 or so, (maybe a little more now).
The CLS series does require a careful in-room setup, but are something really special when done right.
Good luck on your search...
When I was a dealer, I always had a pair of the older model on demo when the new model came out. I was able to A/B them side by side.
The CLS I (there was never a CLSIA. Actually, it was just the CLS). These had a different pattern to the spars inside the panel and were easy to tell that they were the CLS versus the later model. The CLS would drop down to around .6ohms and was an amp eater.
The CLSII was designed to be a little easier on amps. These would drop down to around .8-.9ohms.
The CLSIIA was developed very shortly after the CLSII came out and was field retrofittable. It was a pretty easy mod to do and opened the speaker up quite a bit and smoothed it out over the CLSII, but still was pretty hard on amps.
The CLSIIZ was developed to be even easier on amps. These drop down to around 1.2ohms and did indeed help with the amp situation.
When I was able to hear them side by side through their evolution period, I liked the CLSIIA the best. Many owners will say the CLSIIZ was the best, but I’m not sure that everyone had the chance to hear them side by side. This is just my opinion, but Gayle Sanders once told me that he thought they had lost some of the "magic" & "sparkle" when they went from the IIA to the IIZ, but it had to be done to try to address the amp problem.
Martin Logan has a serial number decoder to help you know which version you have and to tell how old the electronics and panels are. I have a pdf copy if you want it.
The ML panels last around 12-15 years before they need replacement. Unfortunately, ML has really raised the prices of replacement panels. I replaced mine a few years ago for $890 plus shipping. They are now $2700 plus shipping.
There is a guy named Russ Knotts that will rebuild a pair for around $600 or so, (maybe a little more now).
The CLS series does require a careful in-room setup, but are something really special when done right.
Good luck on your search...