sorenb Posted June 27, 2015 Report Posted June 27, 2015 I would definitely go with the 550v caps. depends on the voltage range of your power. if you go with standard voltage +/-5% you might squeeze in to the 500v but if its standard voltage +/-10%, that's pushing it. So if 500V or 550V is needed one needs two times the cap in order to be able to serialise and still maintain the capacitance?
s_r Posted June 27, 2015 Report Posted June 27, 2015 might be a stupid question, but don't you need the 20k resistor to maintain a drop of 10V? something like (Vcc-10V)/0,5mA = total value of two resistors in series ? so in case one cannot get the resistor values needed, the 20k can be changed a bit up/down as long as there are 10V across ...right? Pretty certain he means the two 390kOhm resistors. For 450V you'd sub in two 440kOhm (or any two that add up to 880k).
sorenb Posted June 27, 2015 Report Posted June 27, 2015 Pretty certain he means the two 390kOhm resistors. For 450V you'd sub in two 440kOhm (or any two that add up to 880k). I guess that is obvious .... but not that obvious that you need to maintain 10v across the resistor that is currently 20k ...it might be higher/lower as far as I can figur out.
insanity Posted June 27, 2015 Report Posted June 27, 2015 I have some question concerning the SIC Psu What is the rating of the 330pf caps? 1kv? Why do the 500k bleeding resistors need to be so big? Is it just because they need to be rated more than 550v and nothing but the 3w is available with such a rating?? Furthermore I wanted to ask if there would be any noticeable benefit in using the goldenreference LV supply instead of the tight and small standard LV supply?
kevin gilmore Posted June 27, 2015 Author Report Posted June 27, 2015 (edited) 330pf caps are 1kv on the old power supply 2 caps were in series with a resistor on each cap, so the voltages just made the ratings of the resistors, actually slightly more than ratings on the 500v supply. the new supply is only one cap, and that would exceed the voltage of a rn60 so the 3 watt (or 1 watt) things are actually rated for voltage. obviously you need only .5 watt could go with 2 resistors in series, room for that. sorenb wants to use the higher quality lv supply. don't know if it makes any difference, but the lower noise might definitely make it better. Edited June 27, 2015 by kevin gilmore
kevin gilmore Posted June 27, 2015 Author Report Posted June 27, 2015 Pretty certain he means the two 390kOhm resistors. For 450V you'd sub in two 440kOhm (or any two that add up to 880k). yep, exactly like it works on the original supply
s_r Posted June 27, 2015 Report Posted June 27, 2015 Any problem with using these two for the higher wattage resistors on the PSU? Also, how exactly is the output current for the amp boards calculated?
kevin gilmore Posted June 28, 2015 Author Report Posted June 28, 2015 those are fine current limit is .75 volts across the 10 or 5.1 ohm resistor, or whatever value you stick in there
mwl168 Posted June 28, 2015 Report Posted June 28, 2015 As promised, I started a separate thread for the KGSSHV Carbon and the GoldenReference HV PS group buy: Due to the options for different PS boards, I need to ask those that have already expressed interest in the GB here to read the new thread and post your response again over at the new thread. I am also going to need some help checking the boards. Thanks! 1
insanity Posted June 28, 2015 Report Posted June 28, 2015 (edited) Is this the correct part for the tantalum cap in the psu? http://www.mouser.ch/ProductDetail/AVX/TAP476K035CCS/?qs=%2fha2pyFadui71WG8SrZyHASq76qCrPj52xoQTMHd5BCDxIOadHKMAA%3d%3d Never bought a tantalum cap before, but quite expensive... Which heatsink is recommended for the 7815/7915 combo? http://www.mouser.ch/ProductDetail/Aavid-Thermalloy/531102B02500G/?qs=%2fha2pyFaduh5%2fZtDq%2fcwTRGN9T%2fczmwSyk%2fScPY%2fv0hYslkXdMgYig%3d%3d Is this one fine? Length is 1.5inch. Or is 1inch also sufficient? Edited June 28, 2015 by insanity
spritzer Posted June 28, 2015 Report Posted June 28, 2015 For the impatient ones, one of my Carbon PCB orders was thought to be lost so I had to double up the orders. It turned up on Friday though so now I have too many PCB's. This version hasn't been tested but it is just a smaller take on the ones I've been using so issues aren't likely. These are my own custom boards so smaller than any of the other ones and with shielding on both the front and the back. Price is 47$ each so 94$ for the pair of boards thanks to my expensive tastes and Icelandic taxes...
kevin gilmore Posted June 28, 2015 Author Report Posted June 28, 2015 (edited) here is the final stuff unless someone finds an error http://gilmore.chem....shvcarbonv2.jpg http://gilmore.chem....fetdual2new.jpg http://gilmore.chem....fetdual2new.zip http://gilmore.chem....shvcarbonv2.zip remember on the +/-15 regulators, the tabs are hot, so insulators on both parts, and either plastic screw, or metal screw with the plastic rings on both sides. Edited June 28, 2015 by kevin gilmore
insanity Posted June 28, 2015 Report Posted June 28, 2015 There are also isolated versions of those regulators available from mouser... http://www.mouser.ch/ProductDetail/STMicroelectronics/L7815CP/?qs=sGAEpiMZZMuLLNXTG1MZairwzCPaUz3f5oHn6KFuv5w%3d
kevin gilmore Posted June 28, 2015 Author Report Posted June 28, 2015 (edited) did not know that, makes it easier amp board 5.45 x 4.05 inches 211 holes psdual board 6 x 6.48 inches 287 holes ps single boards 3 x 6.48 inches if there was a 3U heatsink chassis that was only say 10 inches wide on the inside I could do the power boards for that. Edited June 28, 2015 by kevin gilmore
gepardcv Posted June 28, 2015 Report Posted June 28, 2015 Considering all the questions coming in about voltage ratings for the caps on the PSU boards, would you considering updating the silkscreens (for both dual and split) to include all those notes? 1kV for the 330pf, 35V for the 47uF (and note that tantalum is needed). Maybe some others I missed. Should reduce the number of noob questions in the future.
kevin gilmore Posted June 28, 2015 Author Report Posted June 28, 2015 (edited) done, all 5 versions of the power supply fat versions are 5.45 x 4 inches now to find 3U narrow box the fat supplies would work in the 2U next to the amp boards here it is with the fat power supplies in the 2U dissipante chassis http://gilmore.chem.northwestern.edu/chassis2.jpg Edited June 28, 2015 by kevin gilmore
spritzer Posted June 28, 2015 Report Posted June 28, 2015 (edited) No, sleep is for the weak... Edited June 28, 2015 by spritzer
kevin gilmore Posted June 28, 2015 Author Report Posted June 28, 2015 you would be surprised how little time these boards take to make. but but but ray samuels says that gerber files are tens of thousands of dollars each 3
s_r Posted June 28, 2015 Report Posted June 28, 2015 What should the forward voltage on the LEDs be? 2.1V? Also earlier I meant how the current for the amp is calculated, not the PSU. For example, what resistance at the current adjust would yield 20mA per leg?
insanity Posted June 28, 2015 Report Posted June 28, 2015 The Led seems to be the same as usual: 859-LTL-307ELC
kevin gilmore Posted June 28, 2015 Author Report Posted June 28, 2015 too much variance in the parts so you measure the voltage across the testpoints which is a 150 ohm resistor. 3 volts == 20ma
wokstarr26 Posted June 29, 2015 Report Posted June 29, 2015 A suggestion. In the single right fat supply board, the 10m90s on the small heatsink should be mounted on the main al bracket.
chiguy Posted June 29, 2015 Report Posted June 29, 2015 A suggestion. In the single right fat supply board, the 10m90s on the small heatsink should be mounted on the main al bracket. If going along with this, maybe move the 7815 and 7915 on the left board onto the bracket as well.
kevin gilmore Posted June 29, 2015 Author Report Posted June 29, 2015 (edited) that is unnecessary but i could probably do it. the result would be that those parts would get hotter. i have updated the fat boards to be exactly the same size as the amp boards, makes doing the bottom panel easier with the fat power supply boards, definitely fits in this one http://www.ebay.com/...=item3cfcbccb96 iec hole already in the back panel Edited June 29, 2015 by kevin gilmore
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