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jgazal

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Everything posted by jgazal

  1. SR-202 for 250E right now at the other forum.
  2. There are very peculiar entrepreneurial practices in Japan: https://en.wikipedia.org/wiki/Keiretsu. Not saying it is a good or a bad thing, just different cultures.
  3. I would like to understand this also. There is no physical discontinuity between both ends of dynamic voice coil. There is some resistance to direct current. If a certain level of direct current flows through the voice coil, heat is produced and the voice coil can be damaged. There is a physical discontinuity between both stators. Direct current cannot flow from one stator to another in a functional condition. Direct current through the stators means failure (dielectric breakdown of air is achieved and an arc is produced, damaging the diaphragm). This one I learned from Birgir. There is some alternating current flowing in the stators. You can see such alternating current as flowing from one stator to another, but in the imaginary plane. This one I learned from Dr. Gilmore. I like this explanation about capacitors (java required): http://micro.magnet.fsu.edu/electromag/java/capacitor/index.html. The engineers will have to jump in if I said something wrong, but I think there is ground at the transformer primaries, but a bipolar power supply may push pull all the circuit.. edit: said something really wrong before...
  4. Thank you again guys. The more I read, the more I realize how little I know. I like the graphite-coated diaphragm. Interesting that Sanders admits that "constant charge" is somewhat controversial given that aluminum coated diaphragms also work well... The idea was to improve voltage swing. So it seems this scheme may introduce more distortion than I thought. So Megatron is the only way to go...
  5. Thank you cetoole, spritzer and beecee. I did not know this article. Now I see the reason for those high ohm resistors in the bias supply ("high resistance, very high resistance"). This led me to my last question. Is there a way to supply a low frequency signal (perhaps DC to 400Hz or DC to 200Hz) with a high resistance amplifier leg? So then you would have voltage swings and more and less "constant charge". Then you would leave the high frequency signal content to the balanced amplifier driving the stators. Is it possible? For instance, is it possible to join the same SRM-323 circuit (with a better current source) and a single ended tube amplifier with high resistance (enough to have voltage swing and “constant charge”)?
  6. That little increase in electrostatic force is an interesting fact. Is there any published graph "bias voltage" (i.e. 0V to 1000V) vs. electrostatic force (with i.e. constant 100V DC at one stator)? Is it possible to simultaneously drive the stators and the diaphragm with audio signal? Well, if it were possible, Stax would have already adopted such scheme from the very beginning... I thought using a third amplifier board, but running the signal at higher voltages than the balanced legs driving the stator. That implies a six pin headphone plug and a balanced + single ended all-in-one amplifier. Besides increasing costs, what are the side effects of such scheme?
  7. What is the advantage of LiFePO4 batteries? Does the PS need any alteration when adopting SiC diodes?
  8. I am not against exposing children to music and proper education as soon as possible. But which are the healthy limits? http://mje.mcgill.ca/index.php/MJE/article/download/8237/6165 This particular child possibly will grow-up self-confident.
  9. Who said about Russians and camcorders? http://www.youtube.c...ed/G6r5q_jXE04" http://youtu.be/G6r5q_jXE04
  10. Related: http://www.japantimes.co.jp/print/nn20120106f1.html
  11. Does that mean no more DIY? Did the SR-001MK2 system used to have neutral bass response? Sorry asking that, but I have never heard it.
  12. Three Lions / Getty Images Women firefighters direct a hose after the Japanese attack on the US naval base at Pearl Harbor. http://photoblog.msn...ks-70-years-ago
  13. Try to tell her this: Kaplow, Louis. "The Theory of Taxation and Public Economics". Princeton University Press. 2008. Pages 123-124.
  14. Please be patient with me as I am layman and naive. Definition of physics from wikipedia: Sound is air motion. It is a mechanical force. A transducer transform one form of energy to another form of energy (of course no transducer is perfect and the input energy might be transformed into other forms of undesired energy, such as light or heat). For bulb lamps light is interesting, but heat is not. An electrostatic audio transducer aim to transform electrical energy into sound energy (air motion). I see that electrostatic transducers are driven with little current. I also understand that no current flows through the transducer, which acts as a capacitor, but there is current flow in the signal path (alternated). Dr. KG said once the current pass on the imaginary plain (which I assumed as a mathematical description - square root of -1 – instead of some exotic hidden dimension). If you need to transform electrical energy into sound energy, how a transducer would not “waist” real power on sound energy? Electrostatic transducers could be highly efficient and consume little current, but as far as I understand, it would be impossible to consume no current and to deliver no real power. Is that correct? How much real power a dynamic transducer transform into sound energy (don’t take into account power loss in other forms of energy)? Is that so much different of 1 watt?
  15. http://www.youtube.c...bed/irkxIpNBJJU
  16. It is not the music genre itself, but the way some genres are used to be recorded.
  17. Are IMD measurements in the road map?
  18. Well, then my "static charge on the ear cup" hypothesis is useless. I better shut up my mouth and stop writting things I do not understand...
  19. I feel better now someone replied. I thought I had written something so stupid that you were closing your eyes to my post… It happens to me all the time... @Wachara: I am not an EE also and I admire your skills. I am not saying aluminum is worst than plastic or vice-versa to the purpose you mentioned (hold the driver in its proper place). They might have their acoustical pros and cons. But is it possible the ear cup surface (that is out of the circuit) to become naturally charged? Does that charge affect the circuit? For instance, we would have both stators at peak (outer -450V and inner +450V), the diaphragm at +580V and the earcup with some charge (I do not know, let's say -300V). The earcup charges could build up from touching other insulators (our hands, our clothes, the sofa, the firm molded foam at the wooden box etc.) and not from the circuitry. Well, is that possible? Or the earcup surface stays always neutral? @Spritzer: you are a living Stax encyclopedia (okay, Stax mafia member...). Why they abandoned such metal frame ground? Does that ground keep the ear cup surface always neutral? Are there pictures available?
  20. One additional thought. Suppose you were an Stax engineer and such potential imbalance was really derived from the earcup electrostatic charge. At first I thought a route to earth would help. But it is difficult to add a ground pin to pro connectors. And how to implement such earth connection? If you reach the inner part of the earcup, it would become a pole whenever the stator apply a magnetic force into it, would not? So the mentioned ground should touch only the surface, so the anodized insulation keeps its integrity. But again, if such anodized coating is not a conductor, is an earth connection able to discharge its whole surface? So I start using such earspeaker on dry weather and then the earcup surface touches other insulating materials. The earcup gets charged. Suddenly the imbalance leads the diaphragm into the stators and the diaphragm discharges. Lower volume occurs. I thought time and humid air was enough to discharge the earcup and bring things back to normal. So if I were an Stax engineer I would take the following procedures: 1) replicate a dry environment, with air conditioning, carpets, wool clothes (is Japan dry during winter? I bet it is not dry during Monsoon…); 2) see if such earcup becomes charged (the electrostatic voltmeter); 3) calculate if such charge is able to affect the stator/diaphragm system; 4) if yes, apply anti-static coating to the aluminum anodized coat (more cost). Chances are there is no problem using aluminum anodized earcups without such anti-static coat. I am just thinking about that possibility. There is still the micro dust hypothesis. I do not have any idea how to prove this alternative hyphothesis... Sorry for the long post. p.s.: These subject reminds me Hindenburg (hydrogen). Winds blows and the airship is charged (charge is static). It was connected to the post of the ground winch with wet mooring lines. Then possibly "static" electricity/current (controversial).
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