February 2, 201214 yr So birgir asked for this one, but truth be told, i have been working on it for quite a while, and i have a working prototype. Specs: DC to 200khz +0, -.2 db Slew Rate >350 volts per microsecond Thd < .01% Voltage Peak to Peak, Stator to Stator 2950 http://gilmore.chem....n.edu/togte.pdf This is not for the faint of heart. The amp actually can go higher in voltage by a bit, but anything over +/-750 for the power supply gets to be Very difficult to regulate well. The +/-250 is actually resistor dividers off the +/-750 Its the only push pull fully dc coupled electrostatic amp that i know of Since this schematic i have replaced the 2s3840 with ksc5026 which is a higher voltage transistor and a better match for the 2sa1968. Edited February 2, 201214 yr by kevin gilmore
February 3, 201214 yr Does TOGTE stands for The One Gilmore To End (It all)? Check the title of the thread.
February 3, 201214 yr Gazing upon all this high voltage goodness gives me a woodie! @KG - Got any proto pix? So what do you use for a psu? Jumper cables to the nearest substation? Is everything rated for ~1KV, or are you stacking components?
February 3, 201214 yr Doh. I'll never figure out why that didn't connect. I'll be honest, when I saw the filename, it took a few moments to put it together. It didn't click for me immediately either.
February 3, 201214 yr Author The high voltage power supply is the kgsshv supply with all the pnp's replaced with 2sa1968's and the 2sc3840 replaced with ksc5026, and the pass fets replaced with the 900 volt versions. (and changes to the zener string and feedback resistors) Eventually due to the march to surface mount, i will be making DPAK to TO220 converter boards so that we can use the 2sa1413, or the ROHM parts in place of the 2sa1486. This will apply to the kgsshv too. The low voltage (well +/-85 is low voltage) is a dynahi supply with upgraded parts. Due to all this stuff, and the heatsinks required its going to be the size of the T2. The only person that really needs this is pabbi1. Practically, voltage swings above the bias voltage may do damage to the heaphones, so really +/-600 volt supplies are sufficient. Yes its a stacked transistor design. No other way to do it with solid state. Edited February 3, 201214 yr by kevin gilmore
February 3, 201214 yr Wire some large conducting rubber pads to the output and you'll have an high end defibrillator!
February 3, 201214 yr The only person that really needs this is pabbi1. Yes, but since Cavalli isn't building it I doubt he's interested. Ooh, did I just say that publicly? What is pabbi1 doing with this beast? He's joking about Al's volume levels. Remember how you can hear Al's headphones all the way across the library, in meet conditions? Edited February 3, 201214 yr by swt61
February 3, 201214 yr Could have sworn that I posted to this thread - or am I losing my marbles and imagined it?
February 3, 201214 yr Ahh the things I'm responsible for... As Kevin said, going past +/-600V would be a very bad idea since the amp would have no problem burning up drivers. On the plus side this one has no problem driving Jecklin Floats...
February 3, 201214 yr He's joking about Al's volume levels. Remember how you can hear Al's headphones all the way across the library, in meet conditions? Ah yes. Been a while since our last meet.
February 3, 201214 yr On the plus side this one has no problem driving Jecklin Floats... . This has to be a GOOD thing.
February 4, 201214 yr It is, I don't think anybody has heard what they really can do due to crappy enclosure design and crazy power requirements. The latest transformers have a ratio of 1:120 which is five times what Stax were using... Now for the second problem, find a set of Floats that fit my head...
February 5, 201214 yr It is, I don't think anybody has heard what they really can do due to crappy enclosure design and crazy power requirements. The latest transformers have a ratio of 1:120 which is five times what Stax were using... Now for the second problem, find a set of Floats that fit my head... Even with the transformer driver, the dynamics and speed of this phone were shockingly good. No deep bass at all - Tony Levin's downward stick run in a track on Projekct One literally disappeared with the Float Electrostatics/PS2 transformers, whereas with the Sigmas (not known for their low frequency response), he was present and well accounted for. From memory, the bias voltage is +/- 1200 volts isn't it? I always suspected a well driven set could be giant slayers. They were oddly shaped - I agree - but my head managed to just fit in there. Edited February 5, 201214 yr by John Buchanan
February 5, 201214 yr Yup, bias of +1200V for the PS1 and PS2 series, -1550V for the PS0. Crazy levels but then again these were originally speaker drivers fixed to the plastic frame.
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