I bought a pair of used E160 a while ago. Their sensitivity was very low, and one of the speakers had a mains hum, even lower sensitivity than the other one and a ragged frequency response. I brought the panels to Silberstatic to have them refurbished with new membranes. Dirk Jesberger told me to swap the electrolytic, and that two segment resistors on the panel had burnt out.
When I received the refurbished panels back, I changed the cap. The old one was not terrible (something like 305 instead of 330 µF and a few 10 mR ESR). I also noticed that the HV trim pot was at max and changed it back to the setting of the other board (about 3/4 of the range). Putting everything together, the speakers played, but the one with that had the board I changed the electrolytic on made a popping sound about every 20 s (it takes a little longer at first, and the interval between pops can be anything from 2 to 40 s).
The pops are like an LP record with a really bad scratch. They don't seem to be an electric discharge in the panel as they are a little too dull for that and I can't localize them, i.e. they are the same loudness at the bottom and top of the panel. They also stop the very second I unplug from mains. The speakers will play on after that (and sound absolutely gorgeous), grow slightly fainter after a few minutes but play for maybe half an hour before they residual HV is completely gone.
I just got off the phone with Dirk Jesberger, and he confirms that it is the board and a common problem. He said it was probably a transistor but wasn't sure.
- Does anyone have an idea or a schematic of the Capaciti board?
- I didn't have this popping sound when the panel was in poor condition and the was HV dialed to max. Any chance going back to max will solve the problem? I haven't really dared to do that with the newly refurbished panel.
- Is the fact that the popping diappears the second the mains are disconnected, but takes about 30 s to reappear when mains is reconnected a hint? My idea was that there is a discharge due to overvoltage or a shady component somewhere on the board, but since it takes about 20 s for the voltage to build, this does not really explain why it stops immediately when mains are disconnected.
- Does anyone know what the original voltage setting was supposed to be? Dirk Jesberger said I could probably dial it down because his membranes are more sensitive.
Thanks
When I received the refurbished panels back, I changed the cap. The old one was not terrible (something like 305 instead of 330 µF and a few 10 mR ESR). I also noticed that the HV trim pot was at max and changed it back to the setting of the other board (about 3/4 of the range). Putting everything together, the speakers played, but the one with that had the board I changed the electrolytic on made a popping sound about every 20 s (it takes a little longer at first, and the interval between pops can be anything from 2 to 40 s).
The pops are like an LP record with a really bad scratch. They don't seem to be an electric discharge in the panel as they are a little too dull for that and I can't localize them, i.e. they are the same loudness at the bottom and top of the panel. They also stop the very second I unplug from mains. The speakers will play on after that (and sound absolutely gorgeous), grow slightly fainter after a few minutes but play for maybe half an hour before they residual HV is completely gone.
I just got off the phone with Dirk Jesberger, and he confirms that it is the board and a common problem. He said it was probably a transistor but wasn't sure.
- Does anyone have an idea or a schematic of the Capaciti board?
- I didn't have this popping sound when the panel was in poor condition and the was HV dialed to max. Any chance going back to max will solve the problem? I haven't really dared to do that with the newly refurbished panel.
- Is the fact that the popping diappears the second the mains are disconnected, but takes about 30 s to reappear when mains is reconnected a hint? My idea was that there is a discharge due to overvoltage or a shady component somewhere on the board, but since it takes about 20 s for the voltage to build, this does not really explain why it stops immediately when mains are disconnected.
- Does anyone know what the original voltage setting was supposed to be? Dirk Jesberger said I could probably dial it down because his membranes are more sensitive.
Thanks
No I haven't. What should I be lookign for?
What really surprised my, and I didn't discover this until I was running the Speaker and the rest of the electronics from different switchable extension cords, was that there is no auto-mute when mains is removed from the speaker.
The speaker / board in question wasn't doing the popping sounds before the panel was refurbed and while the HV was still dialled way up and while it still had the slightly aged 330 µF / 35 V capacitor in its power supply. So my guess is its related to one of these three things.
What really surprised my, and I didn't discover this until I was running the Speaker and the rest of the electronics from different switchable extension cords, was that there is no auto-mute when mains is removed from the speaker.
The speaker / board in question wasn't doing the popping sounds before the panel was refurbed and while the HV was still dialled way up and while it still had the slightly aged 330 µF / 35 V capacitor in its power supply. So my guess is its related to one of these three things.
There is a sensing auto on/off circuitry. I would check transistors doing the switching. A good clean of the high voltage components with isopropylalcohol also cant hurt. Did you change all segmentation resistors. IMHO they are too small.
Thanks. The alcohol wash might be a good idea. Dirk Jesberger told me he changed two segmentation resistors I have not yet opened the panels.
How exactly does the auto on/off work? I suppose the mains transformer is on all the time but the auto on/off switches on the supply to the HV cascade? Is it normal for the circuit not to drain the HV supply when the mains is switched off? The other speaker which is working fine also continues playing when the mains is cut.
I suppose you don't have the nominal voltage for the HV supply?
How exactly does the auto on/off work? I suppose the mains transformer is on all the time but the auto on/off switches on the supply to the HV cascade? Is it normal for the circuit not to drain the HV supply when the mains is switched off? The other speaker which is working fine also continues playing when the mains is cut.
I suppose you don't have the nominal voltage for the HV supply?
I only know the voltage required for ESW80/23 and ESW80/14 which is 2800 and 3000 volt respectively. Exact schematic I dont have but it is safe to asume main transformer is always on. When mains is off there is enough charge left in the HV to play music as well as to give you a shock.
If it is gone the moment you unplug the mains, it is a flash-over somewhere in the HV bias circuit, because that is mains-powered.
Most probably on the primary side. Does this circuit consists of a voltage multiplier?
Jan
Most probably on the primary side. Does this circuit consists of a voltage multiplier?
Jan
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The membrane tends to the stator (sticking), but the membrane tension returns it to its original state, at this time a "clap" is heard.
The reason may be too high a polarizing voltage or too low-resistance conductive membrane coating for a given bias.
In your particular case, you need to reduce the polarizing voltage on the membrane by any available method.
The reason may be too high a polarizing voltage or too low-resistance conductive membrane coating for a given bias.
In your particular case, you need to reduce the polarizing voltage on the membrane by any available method.
But he says it disappears the moment the mains is removed. That does definitely not point to a sticking membrane - the membrane HV does only change very slowly with removal of the mains.
The most logical cause, when it stops when the mains is removed, is something that is fed by the mains - the HV multiplier and associated circuitry.
Jan
The most logical cause, when it stops when the mains is removed, is something that is fed by the mains - the HV multiplier and associated circuitry.
Jan
And I didn't write that the membrane stuck to the stator, but wrote that the membrane tends to the stator, but the tension is sufficient to return it back, time passes and the membrane again tends to the stator, the charge from the membrane goes to the stator and the membrane returns to its original state.
Reducing the bias will eliminate this problem.
Moreover, if the problem is not eliminated, then over time the membrane will weaken in tension and will stick to the stator, but the “pops” are a harbinger of membrane sticking.
Reducing the bias will eliminate this problem.
Moreover, if the problem is not eliminated, then over time the membrane will weaken in tension and will stick to the stator, but the “pops” are a harbinger of membrane sticking.
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As far as I know any 'bending' of the film should not generate pops unless there is a voltage breakdown. Because of the PVC insulated wire this is very unlikely. Either the Mylar is stable (as expected after refurbishment) either it isnt. Swapping HV board will make clear if the problem is in the board or the element itself.
Jan, I don't have a schematic. I will likely have to analyze the circuit and draw one.
There is definitely a cascade of 1N4007 diodes and 33 nF MKP capacitors, 13 of them, if I remember correctly. If it is mains driven, that will result in way more than 3 kV. I wonder how the HV voltage setting works.
And I will have to research how to measure the voltage safely, such as using very large resistors as a voltage divider.
Havun, are you saying there are two stable positions for the membrane, center and somewhere closer to one stator, and it oscillates between these positions? I think this is unlikely:
1. The HV circuit and panel have a very long time constant on the order of 20 Minutes for 1/e. Cutting the power stops the popping immediately, no matter whether I do it right after a pop or just before I would expect the next pop.
2. Given mechanical tolerances, I would expect this to happen at a single point, but I can't hear a particular location that the pops originate from
3. I would expect bass notes to bring the membrane closer either stator and acerbate the popping, but the frequency is absolutely independent of what music I play, how loud it is or wether I don't play anything.
There is definitely a cascade of 1N4007 diodes and 33 nF MKP capacitors, 13 of them, if I remember correctly. If it is mains driven, that will result in way more than 3 kV. I wonder how the HV voltage setting works.
And I will have to research how to measure the voltage safely, such as using very large resistors as a voltage divider.
Havun, are you saying there are two stable positions for the membrane, center and somewhere closer to one stator, and it oscillates between these positions? I think this is unlikely:
1. The HV circuit and panel have a very long time constant on the order of 20 Minutes for 1/e. Cutting the power stops the popping immediately, no matter whether I do it right after a pop or just before I would expect the next pop.
2. Given mechanical tolerances, I would expect this to happen at a single point, but I can't hear a particular location that the pops originate from
3. I would expect bass notes to bring the membrane closer either stator and acerbate the popping, but the frequency is absolutely independent of what music I play, how loud it is or wether I don't play anything.
Did you swap the HV boards? Assuming one faulty board the problem should move to the other speaker when swapping the boards. If it doesnt matter the problem is in the ESL.
If in the board also check the safety resistor at tbe output of the kaskade
If in the board also check the safety resistor at tbe output of the kaskade
I haven't swapped the boards yet. Bolting the panels to the "feet" was a major pain, as was putting the board I exchanged the electrolytic on back into the foot. But I will do that once all other options are exhausted.
By safety resistor you mean a resistor at the end of the cascade? I'll look for that. It could well be fried considering someone turned up the voltage to max. I just wonder why there wasn't an issue with the old membrane.
By the way, after I wash the board, is coating it with plastic spray a good idea?
By safety resistor you mean a resistor at the end of the cascade? I'll look for that. It could well be fried considering someone turned up the voltage to max. I just wonder why there wasn't an issue with the old membrane.
By the way, after I wash the board, is coating it with plastic spray a good idea?
Yes it is the resistor at the end of the cacade. It could be 'open' although I never have seen one myself.
Plastikpray is good. Did this myself. Ofcourse after you have checked that the components are fine and after a good clean
Plastikpray is good. Did this myself. Ofcourse after you have checked that the components are fine and after a good clean