CLS II panel quirks

[The Observatory]

Hi Forum,
now that the aches with my Sequels were solved in no time at all through ONE post on this forum (how much more efficient can you get - thanks to you Forum guys), on to the next problem area, one of my CLS II panels.

I am listening to the CLS IIs for about 6 months now and notice ever so often (I know this is vague but I have not been able to ascertain any pattern or specific situation yet) that one and the same panel goes down in loudness by about 70% (estimate) after about something like 20 minutes playing. I reversed the cables to the other stereo channel, have used four different power amplifiers (from low 80 W output to way beyond the panels capacity), all the same. I turn them off, after some time (hours to a day, not minutes) I turn on the power again, the panels sound equally loud. Then, same game again, my left panel goes "dim" but not after the same time as before. It is also independent of the music and loudness I play them at.

I have vacuumed them, have not had them under the shower yet but they do not look dirty.
What I have not done yet is switch the electrics boxes from one panel to the other. Will do that next.

When they play with equal loudness, they sound great (yes, I have read all the bass threads!! More than interesting - fascinating). They also still sound great when the one panel goes down in loudness. It plays all across the panel all the time; no dead areas. I slide my ears across and up and down. Given enough amps in the amplifier, I can get them to sound equally loud by using the power output knob for the weak channel but I do not feel comfortable doing that. The left panel remains at that low output level then, it does not get any weaker even after many hours playing.

My CLS IIs are used in a quadrophonic system as front speakers with two Aerius as rear speakers in a Swiss wooden "barn" from 1837 in its 40' x 22' A-frame attic. I use spikes on a granite plate under the CLS IIs, mainly listen to classical music, and, yes, am thinking about a subwoofer setup. When I added the Aerius as rear speakers, the bass question was helped a bit.

Does anyone have an idea what could be the problem with the CLS II panel going down in loudness level?

Thanks folks,

Arthur

(I'll use smilies when I feel more familiar with these creatures)

 

[roberto]

Hi Forum,
now that the aches with my Sequels were solved in no time at all through ONE post on this forum (how much more efficient can you get - thanks to you Forum guys), on to the next problem area, one of my CLS II panels.

I am listening to the CLS IIs for about 6 months now and notice ever so often (I know this is vague but I have not been able to ascertain any pattern or specific situation yet) that one and the same panel goes down in loudness by about 70% (estimate) after about something like 20 minutes playing. I reversed the cables to the other stereo channel, have used four different power amplifiers (from low 80 W output to way beyond the panels capacity), all the same. I turn them off, after some time (hours to a day, not minutes) I turn on the power again, the panels sound equally loud. Then, same game again, my left panel goes "dim" but not after the same time as before. It is also independent of the music and loudness I play them at.

I have vacuumed them, have not had them under the shower yet but they do not look dirty.
What I have not done yet is switch the electrics boxes from one panel to the other. Will do that next.

When they play with equal loudness, they sound great (yes, I have read all the bass threads!! More than interesting - fascinating). They also still sound great when the one panel goes down in loudness. It plays all across the panel all the time; no dead areas. I slide my ears across and up and down. Given enough amps in the amplifier, I can get them to sound equally loud by using the power output knob for the weak channel but I do not feel comfortable doing that. The left panel remains at that low output level then, it does not get any weaker even after many hours playing.

My CLS IIs are used in a quadrophonic system as front speakers with two Aerius as rear speakers in a Swiss wooden "barn" from 1837 in its 40' x 22' A-frame attic. I use spikes on a granite plate under the CLS IIs, mainly listen to classical music, and, yes, am thinking about a subwoofer setup. When I added the Aerius as rear speakers, the bass question was helped a bit.

Does anyone have an idea what could be the problem with the CLS II panel going down in loudness level?

Thanks folks,

Arthur

(I'll use smilies when I feel more familiar with these creatures)

Hola Arturo...just thinking loud, it looks that you have a panels foulty solder joint. Usually is the blue cable at the bottom of the panel. To solder it back, you have to take it apart and need at least 100 Watt soldering station. Contact Jim Power, at Martin Logan ([email protected]) for the right procedure. Happy listening,
Roberto.

 

[The Observatory]

CLS II loudness remedy attempt

Hola Roberto,

cannot wait to get the soldering gun out but it is probably a wise thing to catch some sleep first. Will let you know how I fare before I trouble Jim.

Thanks for the suggestion.
Arthur

 

[Jeff Zaret]

Arthur,
Have you tried and swapping the electronic boxes to see if the problem moves? I do not remember if you said that.

Jeff

 

[Gordon Gray]

Cold solder problem

I agree with Roberto's hypothesis. Sounds like a classic cold solder joint problem. It usually occurs once the electronics have a chance to warm up.

GG:rocker:

 

[enilsen]

It sounds to me like something simpler than a soldering problem. I've notice things like this when the power cable has loosened at the plug to the box. Just wiggle it a bit and the sound re-appears as if the bias charge was turned off. (could be a loose fit in the plug)

There is no heat in the CLS that should impact the soldering points and cold solder issues would be more significant then just a loss of volume after a short playing time.

 

[amey01]

Don't shower them until you've made absolutely sure it's not an electronic problem. It definitely dosen't sound like a dust/dirt/panel issue, but as Roberto said, more likely a problem somewhere in the HV circuitry.

 

[The Observatory]

CLS II loudness problem solved

Hi and thanks for the replies to my problem. As expected, the answer to the problem was found and solved. This is what I did:

Following Jeff's advice, I swapped the boxes first (although I had the soldering gun ready). While undoing the bolts to the electronic box on the panel in question (the one that changed loudness) I discover a 20" long crack in the outside wood panellig bar from the bottom upwards. That crack goes all the way through the wood and was fastened together with two giant (4" and 6" long) wood screws painted black (one of the previous owners must have repaired that). The crack - following Murphy's law - is on the side where the cables enter the wood inside a 1/4" or so hole. There is no way the woodscrews can have avoided the cables. So, I assume that they were producing a short of some sort.

I have swapped the electronic boxes anyway and played the panels for some hours now, even swapped amplifiers and cables (twin Marantz 4300 and PM 80 to a single Philips Audio Labs producing some 2x 290 W into 8 Ohms). The panels both play with even loudness all the time! This really sounds much better.
Needless to say, I did not put the woodscrews back and will have to fill the crack with wood glue and clamp the frame up over night.

When analysing the problem. I can only assume that it was the wood screws touching and chafing on the cables inside. And I do not dare to put them back for fear they might rip a cable altogether. Of course, I wiggled all the cables inside and going to the box. Everything seemed tight and producing a good contact.

Among many program sources, I checked the loudness level with the Erato CD "Orfeo" by Monteverdi producing many situations where you have voices, lutes, instruments, etc. changing direction all the time becoming very noticible - all seems to work perfectly.

Thanks again for the help. I really appreciate that. What a wonderful way to join the Forum!

Arthur

 

[roberto]

Hi and thanks for the replies to my problem. As expected, the answer to the problem was found and solved. This is what I did:

Following Jeff's advice, I swapped the boxes first (although I had the soldering gun ready). While undoing the bolts to the electronic box on the panel in question (the one that changed loudness) I discover a 20" long crack in the outside wood panellig bar from the bottom upwards. That crack goes all the way through the wood and was fastened together with two giant (4" and 6" long) wood screws painted black (one of the previous owners must have repaired that). The crack - following Murphy's law - is on the side where the cables enter the wood inside a 1/4" or so hole. There is no way the woodscrews can have avoided the cables. So, I assume that they were producing a short of some sort.

I have swapped the electronic boxes anyway and played the panels for some hours now, even swapped amplifiers and cables (twin Marantz 4300 and PM 80 to a single Philips Audio Labs producing some 2x 290 W into 8 Ohms). The panels both play with even loudness all the time! This really sounds much better.
Needless to say, I did not put the woodscrews back and will have to fill the crack with wood glue and clamp the frame up over night.

When analysing the problem. I can only assume that it was the wood screws touching and chafing on the cables inside. And I do not dare to put them back for fear they might rip a cable altogether. Of course, I wiggled all the cables inside and going to the box. Everything seemed tight and producing a good contact.

Among many program sources, I checked the loudness level with the Erato CD "Orfeo" by Monteverdi producing many situations where you have voices, lutes, instruments, etc. changing direction all the time becoming very noticible - all seems to work perfectly.

Thanks again for the help. I really appreciate that. What a wonderful way to join the Forum!

Arthur

Good to know that it was just a minor problem...and welcome again...happy listening,
Roberto.

 

[karma]

HI Observ,
Great that you found the problem. That's a problem no one could expect or troubleshoot over the net. Very weird!

Sparky