Hi all,
After my speakers were out of use for about a year, I noticed a loss of high frequencies and transparency. The year of production is 2002 and it was to be expected that it was time to replace the esl panels. Before buying new panels, I checked the bias DC voltage (1Gohm in series with a multimeter) and the voltage was 22.3V (2230V), also connection between step up transformer and front/rear stators. ML support confirmed that the voltage is within the expected range. I also checked the capacitors in the crossover. 10 years ago I replaced Solen and Benic with Duelund and Mudorf and the result was even more detail and a more natural sound. I also disconnected Jumper J1 to disconnect the "ML DEC" limiter circuit and the sound was still just as bad. I was sure the panels were faulty. After replacing the new panels, the sound did not change. I tried another amplifier, but no change in the sound. Then I ordered new step up audio transformers for both speakers but that didn't help either. I have no idea what to do. Is it possible that the new ESL panels are defect? ML support told me that every panel is tested before delivery. I tried another pair of speakers (they are not ESL, standard dynamic speakers) and the details, treble sone sound much better. I hope someone can give me some advice.
After my speakers were out of use for about a year, I noticed a loss of high frequencies and transparency. The year of production is 2002 and it was to be expected that it was time to replace the esl panels. Before buying new panels, I checked the bias DC voltage (1Gohm in series with a multimeter) and the voltage was 22.3V (2230V), also connection between step up transformer and front/rear stators. ML support confirmed that the voltage is within the expected range. I also checked the capacitors in the crossover. 10 years ago I replaced Solen and Benic with Duelund and Mudorf and the result was even more detail and a more natural sound. I also disconnected Jumper J1 to disconnect the "ML DEC" limiter circuit and the sound was still just as bad. I was sure the panels were faulty. After replacing the new panels, the sound did not change. I tried another amplifier, but no change in the sound. Then I ordered new step up audio transformers for both speakers but that didn't help either. I have no idea what to do. Is it possible that the new ESL panels are defect? ML support told me that every panel is tested before delivery. I tried another pair of speakers (they are not ESL, standard dynamic speakers) and the details, treble sone sound much better. I hope someone can give me some advice.
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Is it the whole midrange and treble range that's depressed or just the treble frequencies?
Is it both speakers?
Is it both speakers?
Hi Mattstat,
The midrange sounds dull, without detail, but loud. Overall heavy sound.
Both speakers sound equally bad.
Today I replaced all the capacitors, diodes 1N4007,10Mohm in the voltage multiplier (Bias unit). Also all the zener diodes in the regulation in front of the voltage multiplier. The triac that regulates the ON/OFF function has also been replaced. Now I measure the bias voltage 2300V. I measured 254V AC on the secondary of the main transformer. The same values were measured on both speakers. Unfortunately I did not notice any improvement in the sound. I measured the capacity between the front and rear stator. 2nF was measured. Old ESL panels have the same 2nF capacity.
The midrange sounds dull, without detail, but loud. Overall heavy sound.
Both speakers sound equally bad.
Today I replaced all the capacitors, diodes 1N4007,10Mohm in the voltage multiplier (Bias unit). Also all the zener diodes in the regulation in front of the voltage multiplier. The triac that regulates the ON/OFF function has also been replaced. Now I measure the bias voltage 2300V. I measured 254V AC on the secondary of the main transformer. The same values were measured on both speakers. Unfortunately I did not notice any improvement in the sound. I measured the capacity between the front and rear stator. 2nF was measured. Old ESL panels have the same 2nF capacity.
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Just to clarify, is the amplifier you are running now the same amp you were running before the speakers went in storage? (Wolcott Presence, I assume from your pictures) What I'm trying to get at is whether the amplifiers you recently tried were ever successfully used with the Ascents previously.
What solid state amp did you try? Martin Logans do tend to be a very demanding load.
Is the loss of detail a measurable amount of frequency response difference or are you describing something on the order of losing what you feel you gained with crossover capacitor upgrades? A bias supply problem would typically affect the entire range covered by the electrostatic panel. If you're saying it's loud, that seems to indicate the problem is elsewhere.
The ML Ascent is a hybrid speaker, with conventional woofer, so low bias could produce the effect you are observing. Low bias will bring down the output of the ESL portion, but not the woofer. Therefore, the system could sound "off balance" and lacking in mids / highs.
Are you driving both woofer and ESL in parallel from one amplifier channel, or bi-amping?
Are you driving both woofer and ESL in parallel from one amplifier channel, or bi-amping?
If both speakers sound effectively the same, it would be hard to believe that it's a component or panel failure, since it's pretty unlikely that two speakers would fail in exactly the same way.
Sheldon
Sheldon
You have my sympathy as I have Ascent'i' and will follow along with positive thoughts.
Are you hearing the woofers? If you disconnect the rear jumpers to the bass to play only the ESL, do you get any sound at all? And old panel and new panels have the same symptoms, on both sides? Very odd...