CLS IIz - newbie confusion/1 speaker low

Hi,
My 2nd hand CLS IIz's have been performing great for the 2 years of ownership.
Suddenly this weekend one speaker is low. No distortion, and no weird noises....just low.

I obviesly feared it might be the panels, and got a quote for new ones........it's 4500 USD and 15-20 weeks of delivery time to go that road. Thats is the way to go if the panels are gone.....but if they are not:banghead:
I search this forum, and find that I can find out the age of my panels based on the serial#. I have cs1fc709 and cs1fc708. That does not match the code in the serial number decoder sticky in here.......why?.
And why are they consecutive numbers, when the panels are visually not the same?(the spars are not horisontally symmetrical on the low speaker).

I look into the electronics boxes, and see that they are identical.......no LEDs, and no signs of components gone off. Its all nice and tidy(see pic attached).

Perhaps someone that is more familiar with ML CLSs can tell me abut my speakers?.

I guess my next step is to switch the speakers, to see if the low end changes side. And if it does, try switching the electronics box on the speakers. But can I do more?. Any pointers are greatly appreciated.

The panels were replacement panels made in March of 1994. They were the 8th and 9th panels made that month. They should be the same? Not sure why they are not.

Hi! To rule out the amplifier causing trouble switch the low speaker connection at the amplifier to other channel. If the low speaker sounds ok when connected to the other channel and the ok speaker low when connected to the other side. Then probably the problem is with your amplifier.

If use more than one source. Then play both sources with the most recent purchased CD or LP.
If low speaker remains low with both sources/players and most recent purchased CD or LP. Then both CD and LP player are ok.

Test by switching sides speaker cables, interconnects, and CLS power cord. If low side changes then cable or interconnect or power cord is faulty. If you have 20 year old CLS power cable then problem may rest with the power cable.

If changed location of loudspeakers, then try moving loudspeakers to the position where they sounded balanced prior to fault developing.

I own a line source loudspeaker and something similar happened to me. One CLS weak output but the other side ok. The ok side terminal wires touched each other while playing music there was a small flash and output from the ok speaker also reduced in volume.

If use banana plugs test whether low speaker plugs are rotated tight and fully inside speaker terminal. Recommended by me to use new spades make sure all connections are tight. with spade connectors highs are better defined compared to plugs.

I know the cavalry will be arriving shortly to sort out your problem.

To simplify what M15 is saying, switch out amp / speaker wire leads and, if required, right / left source IC's to determine if the problem stays.

And of course, check the integrity of all connections.

Thanks to M15 and Gordon Gray. I have been switching wires and moving around this evening, and can confirm that it is the speaker.

I guess when pushing 21 years, panels are excused.

BTW; heres my system.....I don't know either why spars are differently positioned on each panel, but if you look closely, the spars are closer at the bottom on the left side, than on right.
http://www.martinloganowners.com/forum/showthread.php?14252-System-451-(CLS-IIz)

FraggerTuX said:

Thanks to M15 and Gordon Gray. I have been switching wires and moving around this evening, and can confirm that it is the speaker.

I guess when pushing 21 years, panels are excused.

BTW; heres my system.....I don't know either why spars are differently positioned on each panel, but if you look closely, the spars are closer at the bottom on the left side, than on right.
http://www.martinloganowners.com/forum/showthread.php?14252-System-451-(CLS-IIz)

Click to expand...

You can also move the electronics boxes between speakers, and see if the problem follows the box, or the panel.

If you do what Peter Hogan suggests and the problem moves with the interface take a look at this thread I posted earlier in the year with the same problem.

http://www.martinloganowners.com/fo...-bite-the-dust&p=164325&highlight=#post164325

Down toward the bottom of the page was what done to fix my problem.

Good luck.