I have a pair of classic Stax Lambda headphones (earspeakers ) that I have had for more than 20 years. They still sound great, but after all this time the foam inside each speaker has more or less withered away. Not the padding around the ears, but the foam between your ears and the diaphragm. This has made me a little bit concerned.
We are talking about 580V. Does anyone of you with more extensive knowledge than I have about electronics know if this can be a safety problem?
Well, it can jolt you, but it can be hazardous only if it can draw some serious current, 0.2A or more.
I have several pairs of ES phones, and none of them appear to have enough current capability to do more than deliver a mild shock - which I've never experienced. The Koss, Pioneer and A-T units, at least, are sufficiently high impedance that they don't need much current to work. The ESP-9 adapter does run off line power; having done repair work on it I'd say you're way more likely to be hurt by touching the AC line terminals inside than the HVDC supply output. ;-)
We are talking about 580V.
But not much power. Although your driverbox may
consume 50 watts, there isn't much going out in the speakers themselves. A brief googling reveals that at 100 dB it requires 100 V, which using nominal impedance of 50 k? measures up to 0.2 watts power and 0.2 milliamperes current. That's the music signal -- the bias probably delivers much less current. Of course, capacitors may give you more over a short period.
I'm using these: http://www.nakremotes.com/Geo/Stax/Stax_SRD-P_SRD-X.jpg (http://www.nakremotes.com/Geo/Stax/Stax_SRD-P_SRD-X.jpg) , and they don't even consume 2 watts.
OK, so no big worries.
And I guess, if you do get a jolt, you would get it on just one ear or both ears separately, and not as a current from one side of your head to the other?
I have a pair of classic Stax Lambda headphones (earspeakers ) that I have had for more than 20 years. They still sound great, but after all this time the foam inside each speaker has more or less withered away. Not the padding around the ears, but the foam between your ears and the diaphragm. This has made me a little bit concerned.
The loss of padding between the ears and the diaphragm suggests that there has been slow loss of sound quality, particularly smoothness at high frequencies. Since it came on slowly, you probably never noticed it.
We are talking about 580V. Does anyone of you with more extensive knowledge than I have about electronics know if this can be a safety problem?
As a rule, electrostatic speakers have a grounded element between the listener and the parts with high voltage on them. There are also very large current-limiting resistors in series with the high voltage power supply, so any shock you get is like one that you get when you walk across a carpet on a dry day.
The loss of padding between the ears and the diaphragm suggests that there has been slow loss of sound quality, particularly smoothness at high frequencies. Since it came on slowly, you probably never noticed it.
You could be right. At the same time, perhaps this is compensated by my gradual loss of high frequency hearing over the years.
The perfect headphones to grow old with!