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Projects => Build Reports => Topic started by: nzCdog on October 09, 2016, 08:49:11 AM

Title: Power supply! Mk2
Post by: nzCdog on October 09, 2016, 08:49:11 AM
(http://i757.photobucket.com/albums/xx219/nzCdog/IMG_20161009_180632_zpslyzlxgyk.jpg) (http://s757.photobucket.com/user/nzCdog/media/IMG_20161009_180632_zpslyzlxgyk.jpg.html)
(http://i757.photobucket.com/albums/xx219/nzCdog/IMG_20161009_180127_zps2ohskdvu.jpg) (http://s757.photobucket.com/user/nzCdog/media/IMG_20161009_180127_zps2ohskdvu.jpg.html)
(http://i757.photobucket.com/albums/xx219/nzCdog/IMG_20161009_175547_zpslajkx1gi.jpg) (http://s757.photobucket.com/user/nzCdog/media/IMG_20161009_175547_zpslajkx1gi.jpg.html)
(http://i757.photobucket.com/albums/xx219/nzCdog/IMG_20161009_181103_zpsu0nswecu.jpg) (http://s757.photobucket.com/user/nzCdog/media/IMG_20161009_181103_zpsu0nswecu.jpg.html)
(http://i757.photobucket.com/albums/xx219/nzCdog/IMG_20161009_175645_zpsmtq4xddh.jpg) (http://s757.photobucket.com/user/nzCdog/media/IMG_20161009_175645_zpsmtq4xddh.jpg.html)
(http://i757.photobucket.com/albums/xx219/nzCdog/IMG_20161009_180020_zpstenqcfxi.jpg) (http://s757.photobucket.com/user/nzCdog/media/IMG_20161009_180020_zpstenqcfxi.jpg.html)

What to say?  I built a power-supply with this transformer a few years ago, but dropped it.  Oops.  Well this is the remake, decided to fab a pcb.  LM317 based variable power supply, x4 isolated, tweakable DCV from the outside.  Heatsinked to the enclosure.  I use this on the bench, but nice to have a backup for the pedalboard... not that I play much.  This has been sitting almost finished for a while, it was great to knock it off this weekend :)

Oh, and how about those skyscraper electros!?!  ;D
Title: Re: Power supply! Mk2
Post by: m-Kresol on October 09, 2016, 09:05:27 AM
Nice build! I dig that the voltages are variable
One thing though: the GND from the plug to the enclosure should use crimped connectors only and the GND connection to the transformer should not be the same point on the enclosure. Don't ask me why that would matter.
Title: Re: Power supply! Mk2
Post by: nzCdog on October 09, 2016, 09:25:07 AM
Quote from: m-Kresol on October 09, 2016, 09:05:27 AM
Nice build! I dig that the voltages are variable
One thing though: the GND from the plug to the enclosure should use crimped connectors only and the GND connection to the transformer should not be the same point on the enclosure. Don't ask me why that would matter.

Thanks Felix! Oh ok, perhaps there is something like that in our wiring code here in New Zealand.  Class 1 appliances do have some funny rules, I'll have to get the ASNZS out and double check that.  By the way I was in Austria... for all of 2 hours in August!  I was staying in Switzerland for work, rode a bicycle across the Rhine to have a look.  Beautiful part of the world you live in :)
Title: Re: Power supply! Mk2
Post by: m-Kresol on October 09, 2016, 09:50:03 AM
I never understood why a crimped connector is supposed to be stronger than a soldered one. Sure tin is softer than other metals, but it's not likely that the connection would just come loose. But I guess there are reasons for that beyond my understanding of electronics.

funny thing, Vorarlberg (the most western province at the border to Switzerland) is actually were I grew up and were my parents live. I love it there. We've got the lake and the mountains, it's really beautiful to go hiking and do outdoor stuff. A friend visited me there in August and we took the bike around parts of the Lake of constance (we cheated and took the ferry to shortcut)
Title: Re: Power supply! Mk2
Post by: stecykmi on October 09, 2016, 03:28:50 PM
neat build, i like the just-tall-enough caps on the outputs. are those little black disks fuses? i think i've seen that format before but are they resetable? or replace after trip?
Title: Re: Power supply! Mk2
Post by: m-Kresol on October 09, 2016, 03:32:18 PM
I think those are the bridge rectifiers.
Title: Re: Power supply! Mk2
Post by: nzCdog on October 09, 2016, 06:05:40 PM
Quote from: stecykmi on October 09, 2016, 03:28:50 PM
neat build, i like the just-tall-enough caps on the outputs. are those little black disks fuses? i think i've seen that format before but are they resetable? or replace after trip?
Thanks Misha! Yes, a hasty order from element 14... and I will now always double check the height as well as width of electro's! Heh, they still fit. You know I never thought of including polyfuses, it would have been a good idea... Those are bridge rectifiers, as Felix said.  :)
Title: Re: Power supply! Mk2
Post by: nzCdog on October 09, 2016, 06:18:12 PM
Quote from: m-Kresol on October 09, 2016, 09:50:03 AM
I never understood why a crimped connector is supposed to be stronger than a soldered one. Sure tin is softer than other metals, but it's not likely that the connection would just come loose. But I guess there are reasons for that beyond my understanding of electronics.
Well the safety function of the earth is to permit the easy discharge of current to earth in a phase to frame fault, so that a fuse will trigger. Perhaps it is a heat consideration then, which would make sense. A crimp connection will obviously stand the heat of a rush of current better than solder.  I will change this when I get time, thanks for mentioning it, best practice! :)
Title: Re: Power supply! Mk2
Post by: tcpoint on October 10, 2016, 08:45:39 PM
Nice build.  I like the r-core transformer
Title: Re: Power supply! Mk2
Post by: gordo on October 11, 2016, 01:46:21 AM
You had me at the blue glow on the top in the first shot.  Everything else is just bacon.

Very nicely done.
Title: Re: Power supply! Mk2
Post by: nzCdog on October 11, 2016, 07:42:39 PM
Thanks guys :)