goyousalukis Posted October 22, 2004 Report Share Posted October 22, 2004 Hey, so I'm trying my hand at the MidiBox LFO extension by TK :http://www.ucapps.de/midibox_ext.htmlI am building the power supply first:http://www.ucapps.de/midibox_ext/lfo/lfo_powersupply.pdfI bought this transformer from Mouser:http://www.mouser.com/index.cfm?&handler=data.listcategory&D=*553FP3085*&terms=553-FP30-85++&Ntt=*553FP3085*&Dk=1&Ns=MfgrPartNumber%7c%7cSField&N=0&crc=trueIs this ok? I am unsure of how to connect the rectifiers to my transformer. To get 15VAC, I have to tie pins 5 and 7 together and 6&8 together. The schematic shows three outputs to the rectifiers, but I only have 2 - do I just connect each of the 15V outputs to the ~ terminals of the rectifiers?Thanks for your help...Justin Quote Link to comment Share on other sites More sharing options...
illogik Posted October 22, 2004 Report Share Posted October 22, 2004 hey justin, not an answer, but can you find the LFO-ic's? I wanted to build them half a year ago and i couldn't find them (wasn't looking for long though ;) )As for the question; if the transformer is like the ones i used you need to connect the 2 output pins in the middle together (pin 6 and 7 i guess). By connecting the middle ones they become the "ground pin" (sorry for the unprofessional terms guys) ; the transformer will keep the voltage between either of the outside output pins (pin 5 or pin 8 ) and the middle 15Volts.So now you have the 3 outputs to the rectifiers. BUT BEFORE YOU START WITH MY ADVICE ASK/WAIT FOR A SECOND OPINION, I'VE BEEN WRONG BEFORE (high voltages etc.) :-/anyway, good luck!marcel Quote Link to comment Share on other sites More sharing options...
moebius Posted October 22, 2004 Report Share Posted October 22, 2004 Yup, Â illogik is absolutely right ;)You generate +/-15VAC, by connecting secondary windings in series (the ends will give that 30VAC) and "central tap" (those pins connected together) is a reference ground, or 0V.bye, Moebiusp.s. I found ICL3038 from a trashed CT (roentgen) machine laying in the backjard of a hospital. Man, You should have seen "the quality" of the "scan motor control" PCB - I hope it wasn't tested on living subjects as backside of the board had 'bout dozen jumperwires in it. ;) Quote Link to comment Share on other sites More sharing options...
goyousalukis Posted October 23, 2004 Author Report Share Posted October 23, 2004 Thanks for your replies, thats what I've done so far, I just don't seem to be getting the 12V DC yet. I'll double check everything.illogik, I bought the IC's from Mouser part num: 512-LM324AN and 570-8038CCPDJustin Quote Link to comment Share on other sites More sharing options...
dcer10 Posted November 1, 2005 Report Share Posted November 1, 2005 goyousalukis , did you land up finishing your LFO box? I am interested in building one myself, but theres not much information and it looks a little daunting for a beginner! I have built a midibox seqencer, but that had lots of info and a parts list etc as well as an interface laid out already.. Any tips would be appreciated!Thanks,John Quote Link to comment Share on other sites More sharing options...
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