Hi, sorry if this topic has been discussed before. I've built my own ESLs and I've been using one pair for over two years now. They still work well, at least in my opinion. They don't have the problem that my Final ESLs have: losing output.
I bought a secondhand bias supply and I don't know what voltage it produces. I could calculate it, I suppose, but I'm wondering if it is as simple as calculating the circuit output voltage? Or should I get an HV proble and measure it? Are there any articles on how to do this, or how to build a HV probe yourself, if necessary?
Another question is about noise coming from the stators when there is no audio: as soon as I connect the bias supply I hear a hissing sound when I put my ear close to the stators. It seems to be stable. Is this considered to be ok? There are no sparcs (at least not that I'm aware of) or whatsoever. I can see some dust on the glue between the wire stators. Would a speaker grille be a good practice for ESL stators to prevent dust from settling and possibly creating (future) leak-paths? I can change the bias output by using a potmeter. At a certain point / output parts of the diaphragm touches the wire staror. (I can see this when looking at a certain angle with certain light).
I bought a secondhand bias supply and I don't know what voltage it produces. I could calculate it, I suppose, but I'm wondering if it is as simple as calculating the circuit output voltage? Or should I get an HV proble and measure it? Are there any articles on how to do this, or how to build a HV probe yourself, if necessary?
Another question is about noise coming from the stators when there is no audio: as soon as I connect the bias supply I hear a hissing sound when I put my ear close to the stators. It seems to be stable. Is this considered to be ok? There are no sparcs (at least not that I'm aware of) or whatsoever. I can see some dust on the glue between the wire stators. Would a speaker grille be a good practice for ESL stators to prevent dust from settling and possibly creating (future) leak-paths? I can change the bias output by using a potmeter. At a certain point / output parts of the diaphragm touches the wire staror. (I can see this when looking at a certain angle with certain light).
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The simplest and cheapest way to measure HV is with a resistor divider string.
Be sure to observe the voltage ratings of the resistors.You still need a meter
with good isolation. HV probes are very expensive.
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Use a resistor Divider with a Unity Gain opamp buffer to feed the meter, else you will have to include your meters input resistance (if known) to get and accurate voltage measuremnt.
See this thread,
Voltage reading Error issue,
how can test the stator insulation and mylar coating?
Construction of the resistor divider
how can test the stator insulation and mylar coating?
Final Schematics,
how can test the stator insulation and mylar coating?
jer
See this thread,
Voltage reading Error issue,
how can test the stator insulation and mylar coating?
Construction of the resistor divider
how can test the stator insulation and mylar coating?
Final Schematics,
how can test the stator insulation and mylar coating?
jer
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I don't know the specifics of your speaker, but I expect that there should be zero sound with the audio disconnected and ideally also with the amplifier connected.
I suspect you have a small corona discharge happening.
Others might be able to provide better advice, but try turning the speaker on and looking in very dark conditions, your eyes will take about 20 minutes to adapt to the low light. If you are lucky, you will see a small blue discharge that will be associated with a piece of dust, dead bug, or a sharp edge on a conductor which you can later fix. Also try listening closely too, you will be able to hear approximately where the discharge is occurring.
Do not touch the live speaker - it will bite.
I suspect you have a small corona discharge happening.
Others might be able to provide better advice, but try turning the speaker on and looking in very dark conditions, your eyes will take about 20 minutes to adapt to the low light. If you are lucky, you will see a small blue discharge that will be associated with a piece of dust, dead bug, or a sharp edge on a conductor which you can later fix. Also try listening closely too, you will be able to hear approximately where the discharge is occurring.
Do not touch the live speaker - it will bite.
I have set the bias on the Big sound lab ESL panels....Sound lab tell you,too tune the bias pot up till you hear a hissing an then a buzz....an that's with your ears away from the panels....then tune it back down till you cant hear it....so if you put your ear right up to the sound lab panels... youll hear this white noise sound hissing....also dust or a hair.. on the mylar can case this noise....
I say enjoy, less you play your speakers with your ear that close to the panels all the time....good luck
I say enjoy, less you play your speakers with your ear that close to the panels all the time....good luck
Hi, thanks for your replies!
Beside modifying my DIY esl panels and measuring bias voltage I could change / upgrade my amplifier. Currently I use a Harman Kardon HK 680 amplifier to drive my stats:
Harman Kardon HK680 - Manual - Stereo Integrated Amplifier - HiFi Engine
I use second hand trannies that were used in Audiostatic stats. I use a pair of 1:75 per stat. I managed to get an oscilloscope and I was able to detect clipping at +40 volts and -40 volts. The volume knob was at 50% scale. After this new insight I'm wondering how to solve this problem. I would like to be able to play a little bit louder and get a bit more headroom.
Before upgrading to a heavier specced amplifier I'm wondering what would be the maximum power / voltage rating for the Audiostatic trannies? I found some specs of the ES-100 stating 250 Watts maximum. Do you have any idea about what would be safe?
Beside modifying my DIY esl panels and measuring bias voltage I could change / upgrade my amplifier. Currently I use a Harman Kardon HK 680 amplifier to drive my stats:
Harman Kardon HK680 - Manual - Stereo Integrated Amplifier - HiFi Engine
I use second hand trannies that were used in Audiostatic stats. I use a pair of 1:75 per stat. I managed to get an oscilloscope and I was able to detect clipping at +40 volts and -40 volts. The volume knob was at 50% scale. After this new insight I'm wondering how to solve this problem. I would like to be able to play a little bit louder and get a bit more headroom.
Before upgrading to a heavier specced amplifier I'm wondering what would be the maximum power / voltage rating for the Audiostatic trannies? I found some specs of the ES-100 stating 250 Watts maximum. Do you have any idea about what would be safe?
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Good test.
Yes, ESLs run on volts but familiar audio amps are not really appropriate drivers. If your speakers are a suitable load, then the amp voltage rails are your limit.
But if you are harassing the amp due to low impedance load somewhere in the freq compass, the question is how the signal can be configured to avoid it or how otherwise to keep your amp from pooping out.
To get big voltages, some of us use monstrous large amps like 600wpc into low loads.... and even then, loud testing high freq sweeps can blow fuses.
B.
Are you thinking of doing this because of the hiss with no audio? Diagnose: if you mean by 'no audio' that the amp is on and connected but volume turned down, it *could* be the amp noise.
If you mean by 'no audio' the amp disconnected, it definitely is not amp noise and the remaining cause is corona discharge. Your bias may be too high in that case.
BTW simple HV meter: a very large resistor (or a bunch in series) into a 50uA 'draaispoelmeter' (d'arsonval current meter), these can be had cheaply on eBay.
Example: a series R of 100 megohm will give 50uA max meter indication with 5000V. You really shouldn't play with this stuff without some metering facility.
Jan
To check leakage Quad's approach is the best: 47nF film capacitor in parallel with small neon bulb/tube. This circuit connected in series with HV supply output will give you estimation of leakage current. Such bulb can be found in voltage detector (looks like screw driver). Flash repetition rate is proportional to the leakage.
@bentoronto: thanks for your reply. I will do an impedance measurement soon. (should have done that much earlier...)
@Jan Didden: thanks for your directions, I will try the large resistor + draaispoelmeter By 'no audio' I meant: amplifier turned off, esl panels with HS turned on were hissing.
@alexberg: thanks for sharing this idea, sounds like a good upgrade, I will implement it!
@Jan Didden: thanks for your directions, I will try the large resistor + draaispoelmeter
By 'no audio' I meant: amplifier turned off, esl panels with HS turned on were hissing.@alexberg: thanks for sharing this idea, sounds like a good upgrade, I will implement it!
Simple way is just to take any large resistor (say, 200 Ohms, doesn't matter) and wire in series. Then have a few little resistors like 2, 10, and 15.
Plot the resistors' FR impedance just as you would the speaker, with REW but not to bother with their calibration. Then plot the speaker. Easiest way to see how your speaker plot relates to 2, 10, and 15. Exact values not important but using that kind of clean method is important.
B
Hi, I recently connected my big ESL panels. Unfortunately one of them had a small tear in the mylar (5 mm length) which I repaired with tape. It was hissing, especially in that area. The other panel is completely silent. It wasn't a problem because when I was playing music the hissing was inaudible. I used it with success for three weeks.
But today, after moving my panels to a different location in my room, the hissing panel sounds much quieter and more dull than the other panel. I vacuumed it but that didn't improve things. I looked in the dark and raised the bias voltage to max setting but I was not able to detect any sparcs - only the hissing gets louder.
I'm wondering what to do now. It seems there is a big leakage path but I don't know where it is and how to detect it. Could it cause the dull sound? Any suggestions? And is this a common problem for stats?
But today, after moving my panels to a different location in my room, the hissing panel sounds much quieter and more dull than the other panel. I vacuumed it but that didn't improve things. I looked in the dark and raised the bias voltage to max setting but I was not able to detect any sparcs - only the hissing gets louder.
I'm wondering what to do now. It seems there is a big leakage path but I don't know where it is and how to detect it. Could it cause the dull sound? Any suggestions? And is this a common problem for stats?
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Hi, I managed to fix the problem: I opened the stats and found a small piece of paper which I removed. I found some protruding glue parts which I removed. I cleaned some parts with alcohol. Two peaces of insulator strip had an air gap that could become a bias leakage path which I filled with insulator material. After that I assembled the stators again and the problem was solved! I didn't expect that.
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