diablojoy Posted December 20, 2008 Report Share Posted December 20, 2008 Jaycar in oz sell a regulated power supply providing +15/-15 /+5 in kit form from Aud $17.95 each for board and components cat. no.kc5418and a suitable toroidal transformer cat. no. MT2086 from Aud $21.95 with a better price on multiplesas far as i can tell they will ship outside australia if ordering onlineand considering the state of the aussie dollar at the momentit could be worth checking out. http://www.jaycar.com.au Quote Link to comment Share on other sites More sharing options...
stryd_one Posted December 20, 2008 Report Share Posted December 20, 2008 Not too bad at all! Thanks diablo. I wonder how hard it would be to mod to +/-12V...hmmmm Quote Link to comment Share on other sites More sharing options...
lylehaze Posted December 20, 2008 Report Share Posted December 20, 2008 Based purely on the picture given, I'd say you would need a 7812 and a 7912.But that's just a guess. :-)LyleHaze Quote Link to comment Share on other sites More sharing options...
stryd_one Posted December 21, 2008 Report Share Posted December 21, 2008 Yeh that's what I was thinkin. Not bad! Quote Link to comment Share on other sites More sharing options...
diablojoy Posted December 21, 2008 Author Report Share Posted December 21, 2008 I don't think you would need to do even that the regs used for the +15 / -15 are adjustable you only need to change 2 resistors on each side i haven't checked it out fully yet but i think i maybe able to add a couple of trimmers to adjust the outputs so exact voltages can be obtainedthey specify at the moment the standard cct to be within +-5% I want to see if i can improve on thatI will look into the data sheets of the regs and see what i can come up with they areLM317 and LM337. any input would be very much appreciated :) Quote Link to comment Share on other sites More sharing options...
asafnetzer Posted December 21, 2008 Report Share Posted December 21, 2008 Great find, thanks for sharing this.So good to see that they use the LM3x7 regulators, with trimpots added they can be adjusted up to 30V if I remember correctly.This could be a nice substitute for the C64 power supply. Quote Link to comment Share on other sites More sharing options...
Futureman Posted December 21, 2008 Report Share Posted December 21, 2008 Nice! Quote Link to comment Share on other sites More sharing options...
diablojoy Posted December 22, 2008 Author Report Share Posted December 22, 2008 yes modify with 2k trimpots in place of the 1.1k resistorsthen adjust to your requirements roughly 3 volts up to about 25 volts usefullyI guess. current supply will drop off at higher volts and heat becomes an issue at lower volts however between 10 and 18 volts should be good for about 1 ampyou do need to recheck and adjust once you have connected up whatever you are poweringas the voltage will drop roughly by 1 volt once a load is connected .cheers :) Quote Link to comment Share on other sites More sharing options...
Soclt Posted February 17, 2009 Report Share Posted February 17, 2009 Image taken from www.elektronika.ltThose parts starting KP... are 7812 and 7912. Diodes can be replaced with common ones.According to this schematic, you can get +/-15V easily. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted February 17, 2009 Report Share Posted February 17, 2009 Err, that's +/- 12V :) Quote Link to comment Share on other sites More sharing options...
Soclt Posted February 19, 2009 Report Share Posted February 19, 2009 Err, that's +/- 12V :)There are no 7815 and 7915? Quote Link to comment Share on other sites More sharing options...
stryd_one Posted February 19, 2009 Report Share Posted February 19, 2009 In that image? no. Quote Link to comment Share on other sites More sharing options...
diablojoy Posted February 20, 2009 Author Report Share Posted February 20, 2009 have built this as a bench supply and improved it +/-15 within .01 volt adjustable by +/- 1volt from front panel+/- 12 volt is easily acheived also with correct resistor changeswill post mods for both voltages when i can Quote Link to comment Share on other sites More sharing options...
Soclt Posted May 15, 2009 Report Share Posted May 15, 2009 I have built +15/-15 from +12 using two MC34063A. Inductors are a little bit noisy and I can hear sound, when they have load, but this DC-DC changer works perfectly. Online calculator that also draws schematic can be found here: http://www.nomad.ee/micros/mc34063a/index.shtmlUsed these values:Vin:12VVout:-15VIout:200mAVripple:5mVFmin:30kHzSorry for mistakes :) Quote Link to comment Share on other sites More sharing options...
stryd_one Posted May 16, 2009 Report Share Posted May 16, 2009 Hmmm, switchmode... how's the noisefloor? :/Don't you wish *all* PSU chips had their own java schematic generator though? :D Quote Link to comment Share on other sites More sharing options...
lylehaze Posted May 16, 2009 Report Share Posted May 16, 2009 Inductors are quiet noisy Quiet Noisy?? Sounds a bit confusing. :-)Switchers are great for efficiency, but they can create electrical noise that might be heard in an audio signal.Since most of the bipolar supplies needed around here are for audio, I prefer to use linear regulators.But that's just my opinion. I'm really glad it works for you.One thing I really like about 7815/7915 or 7812/7912 is that they are not adjustable, so there's a few less things that need to be adjusted. I just like to keep it simple when I can.Have Fun,LyleHaze Quote Link to comment Share on other sites More sharing options...
Soclt Posted May 17, 2009 Report Share Posted May 17, 2009 Sorry, removed mistake :) Well yes, I made DC-DC changer because it was interesting to test and do it first time. Quote Link to comment Share on other sites More sharing options...
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