Perhaps wash that panels again? It's possible that you have a leakage path from diaphragm to stators at the supports and that is preventing the panel from fully charging up. Do you have increased hum in that quiet panel? That would be an indication that the leakage is pulling down the power supply. As I see it, you don't have much to lose at this point.
Another band-aid would be to reduce the bias voltage on the loud speaker to balance to the weak speaker. This will limit the overall loudness of the pair, and it's not really a fix, but a patch.
Sheldon
Hello Friends,
I am really worried about my right panel not souding loud as the left one, so today I continued to troubleshoot the problem.
I want, I would, understand the root causes, if not to fix the panel, at least to know something more about the ML ES panels.
Today I measured the capacities and the residestance among the 3 "contacts" of the Sequel II panels.
And these are the results:
Left ES panel (the one OK)
- Between Black & Blue: 1.777 nF capacity and >20 MOhm resistance (my instrument limit is 20 M Ohm and it reported overrange)
- Between Black & Red: 0.258 nF capacity and >20 MOhm resistance
- Between Blue & Red: 0.263 nF capacity and >20 MOhm resistance
Right ES panel (the one playing 6dB lower!)
- Between Black & Blue: 1.699 nF capacity and >20 MOhm resistance (my instrument limit is 20 M Ohm and it reported overrange)
- Between Black & Red: 0.258 nF capacity and >20 MOhm resistance
- Between Blue & Red: 0.265 nF capacity and >20 MOhm resistance
Looking at these parameters, I cannot detect any real issue related to the panel physics.
So, not believing that it could really sound different from the other, I decided to swap the entire power supply and high voltage transformer, but, again, nothing changed, so the right panel played 6..8dB lower than the left... and I don't know the causes.
What am I missing?
Many thanks and kind regards,
Andrea
I am really worried about my right panel not souding loud as the left one, so today I continued to troubleshoot the problem.
I want, I would, understand the root causes, if not to fix the panel, at least to know something more about the ML ES panels.
Today I measured the capacities and the residestance among the 3 "contacts" of the Sequel II panels.
And these are the results:
Left ES panel (the one OK)
- Between Black & Blue: 1.777 nF capacity and >20 MOhm resistance (my instrument limit is 20 M Ohm and it reported overrange)
- Between Black & Red: 0.258 nF capacity and >20 MOhm resistance
- Between Blue & Red: 0.263 nF capacity and >20 MOhm resistance
Right ES panel (the one playing 6dB lower!)
- Between Black & Blue: 1.699 nF capacity and >20 MOhm resistance (my instrument limit is 20 M Ohm and it reported overrange)
- Between Black & Red: 0.258 nF capacity and >20 MOhm resistance
- Between Blue & Red: 0.265 nF capacity and >20 MOhm resistance
Looking at these parameters, I cannot detect any real issue related to the panel physics.
So, not believing that it could really sound different from the other, I decided to swap the entire power supply and high voltage transformer, but, again, nothing changed, so the right panel played 6..8dB lower than the left... and I don't know the causes.
What am I missing?
Many thanks and kind regards,
Andrea
AndreaT,
Just to be sure: It's not possible that the lower output is due to some room acoustics or measuring problem, right?
I think if you stay patient and keep your posts about this problem in this thread only, that eventually you will get useful suggestions to help solve the problem. Many experienced members don't check in here so often....
Just to be sure: It's not possible that the lower output is due to some room acoustics or measuring problem, right?
I think if you stay patient and keep your posts about this problem in this thread only, that eventually you will get useful suggestions to help solve the problem. Many experienced members don't check in here so often....
Dear Andersonix,
I would esclude room issues because the measurements before the washing were practically identical (+/- 1dB).
After washing, the 6dB lower output level I mesured twice, at 30 cm (1 foot) and at my LP (2.5 m away, about 8 feet).
I also swapped completely the filter+transformer+high voltage supply unit.
Of course, to dismount the panels I moved my loudspeaker, so I have to say that the current placing is not exactly the original, but it is within 5 cm.
Morevoer, I moved a bit away the "bad" loudspeaker and did other measurements and I got identical results.
I can also exclude measuring problems because I am sure of the correct placement of the mic and I also used a second mic, and I got always the same results.
Many thanks.
Kind regards, Andrea
I would esclude room issues because the measurements before the washing were practically identical (+/- 1dB).
After washing, the 6dB lower output level I mesured twice, at 30 cm (1 foot) and at my LP (2.5 m away, about 8 feet).
I also swapped completely the filter+transformer+high voltage supply unit.
Of course, to dismount the panels I moved my loudspeaker, so I have to say that the current placing is not exactly the original, but it is within 5 cm.
Morevoer, I moved a bit away the "bad" loudspeaker and did other measurements and I got identical results.
I can also exclude measuring problems because I am sure of the correct placement of the mic and I also used a second mic, and I got always the same results.
Many thanks.
Kind regards, Andrea
Better results after 2nd washing with water + alcohol
Hello Friends,
I have a partial good news after have washed again the "bad" panel yesterday.
Yesterday I washed again only my "bad" ES panel. As before, I used worm demineralized water (from my house demineralizer system) and denatured alcohol (about 1.5 litres).
A large soft bristle brush (6 x 1 cm sized) has been used to clean the mylar through the grid.
As shown in the below graph, today (so after 24h drying), I have reduced the unbalance gap below 2dB avg.
I hope that this <2dB unbalance is due to residual himidity (the other panel was washed the 4th August).
Anyway, now the small unbalance is acptable, even because is perfectly linear (see light blue line at the bottom, it is the math "good" / "bad" response.
After this 2nd washing I also realized that the multimeter I used to measure the capacities I mentioned before, is not suited for such a kind of large distributed capacity component.
So, the numbers I posted, are basically erratic and anyway not valued if not measured again with my own multimeter.
The next week I will update you all about.
And if all will be fine, I will post precise instruction on my "own" washing process .
Regards,
Andrea
Hello Friends,
I have a partial good news after have washed again the "bad" panel yesterday.
Yesterday I washed again only my "bad" ES panel. As before, I used worm demineralized water (from my house demineralizer system) and denatured alcohol (about 1.5 litres).
A large soft bristle brush (6 x 1 cm sized) has been used to clean the mylar through the grid.
As shown in the below graph, today (so after 24h drying), I have reduced the unbalance gap below 2dB avg.
I hope that this <2dB unbalance is due to residual himidity (the other panel was washed the 4th August).
Anyway, now the small unbalance is acptable, even because is perfectly linear (see light blue line at the bottom, it is the math "good" / "bad" response.
After this 2nd washing I also realized that the multimeter I used to measure the capacities I mentioned before, is not suited for such a kind of large distributed capacity component.
So, the numbers I posted, are basically erratic and anyway not valued if not measured again with my own multimeter.
The next week I will update you all about.
And if all will be fine, I will post precise instruction on my "own" washing process .
Regards,
Andrea
Bad news! After 2 more days drying-up the bad ES panel got back 5dB lower sensitivity
Hello Worl,
I am going to be crazy...
This is what happened after the 2° washing of my "bad" ES panel:
- After 1 day (24 h) of dry-up I got a sensitivy unbalance within 2dB (see my previous post)
- Today, after 2 more days of dry-up I got a very bad 5dB sensitivity unbalance, as better described in the below measurement graph
The green line at the bottom is the math "good panel sensitivity / bad panel sensitivity", so it is the net unbalance gap.
I really do not understand how this panel worked better when still a bit humit, while getting dryed is working progressively worse.
Anyone has an idea about this very strange behavior?
Many thanks and, again, kind regards,
Andrea
Hello Worl,I am going to be crazy...
This is what happened after the 2° washing of my "bad" ES panel:
- After 1 day (24 h) of dry-up I got a sensitivy unbalance within 2dB (see my previous post)
- Today, after 2 more days of dry-up I got a very bad 5dB sensitivity unbalance, as better described in the below measurement graph
The green line at the bottom is the math "good panel sensitivity / bad panel sensitivity", so it is the net unbalance gap.
I really do not understand how this panel worked better when still a bit humit, while getting dryed is working progressively worse.
Anyone has an idea about this very strange behavior?
Many thanks and, again, kind regards,
Andrea
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Needing instruction to open the ML ES panel
Hello Friends,
I would re-coat my old Sequel II ES panel, so I need to open my Martin Logan Sequel II panels.
Anybody out there is willing to give me precise instruction to correctly separate the back stator from the front stator without tearing the diaphragm film?
I never did it before and I have fear to damage something.
Many thanks in advance!
Kind regards,
Andrea
Hello Friends,
I would re-coat my old Sequel II ES panel, so I need to open my Martin Logan Sequel II panels.
Anybody out there is willing to give me precise instruction to correctly separate the back stator from the front stator without tearing the diaphragm film?
I never did it before and I have fear to damage something.
Many thanks in advance!
Kind regards,
Andrea
I have similar problem on my single CLS panel I washed/opened up/recoated. I now have a leak from mylar to back stator.
I still think there is moisture in foam tape allowing leak of charge, making the panel less efficient.
After playing, unplug the I/F from amp and power, and short the bias on mylar to the stator. See if you get a nice sharp spark. Do teh sameon other panel.
On my CLS, I see /hear a nice sharp spark on unwashed panel ,while on the washed panel that I have a 6db difference, I barely see / hear a spark. This is confirmed by my Neon Bias Charge indicator.
Still think the moisture is leaking charge, so I am going to wait a week to better dry before trying anything new...
I still think there is moisture in foam tape allowing leak of charge, making the panel less efficient.
After playing, unplug the I/F from amp and power, and short the bias on mylar to the stator. See if you get a nice sharp spark. Do teh sameon other panel.
On my CLS, I see /hear a nice sharp spark on unwashed panel ,while on the washed panel that I have a 6db difference, I barely see / hear a spark. This is confirmed by my Neon Bias Charge indicator.
Still think the moisture is leaking charge, so I am going to wait a week to better dry before trying anything new...
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