schematics/PCB for +/- 18V, 48V power supply?

[blakbeltjonez]

i'm looking to either buy or build a relatively simple/cheap +/- 18V power supply (1A or so ) with 48V phantom power (anywhere from $30-60 or so). i've looked around the metas but haven't seen exactly what i need.... anybody know where i can either buy a ready to go supply, or maybe a parts list/schematic, even PCB artwork that i could knock out myself?

 

[blakbeltjonez]

whoops....spoke too soon - back to searching the meta's and saw Fabio's power supply for the 312's .... but after looking at the .pdf schematic it's not entirely clear to me.

 

[Family Hoof]

http://www.beatbazar.com/guests/ssltech/kps-1/index.htm

 

[blakbeltjonez]

nice...prayers answered - thanks for the heads up, Hoof!

 

[Greg]

SSLTech also has a nice +/- 18V and 48V schematic. It's a bit simpler than Fabio's... Fabio's also has the 5V for relays. You could probably even build SSLTech's on perf board.

 

[blakbeltjonez]

Jeeee-zus... looking through mouser.com's selection of transformers is like making a sandcastle one grain of sand at a time. ugh....


the transformer that's listed in keith's PSU is a 20v-0-20v transformer - but nothing's listed like that on the Mouser site. unfortunately i am transformer illiterate, hence the FNG questions... so:

would a transformer listed as 36V CT, 20V = 20-0-20? i'm guessing that both secondaries wired together would give you close to 40v, wired with the secondaries separate would give you two independant 20V legs with a 0v center?

if anyone could fill in the blanks, i would be grateful.... a model #, etc. for an appropriate transformer would be great too! thanks, and sorry for so many N00b 101 questions..

 

[tmbg]

What about these?

http://www.jlmaudio.com/JLM%20Power%20Supply.htm

I think I want to order some of those!

 

[Family Hoof]

[quote author="blakbeltjonez"]the transformer that's listed in keith's PSU is a 20v-0-20v transformer - but nothing's listed like that on the Mouser site. unfortunately i am transformer illiterate, hence the FNG questions... so:[/quote]
Keith's (aka SSL Tech) supply calls for a mains transformer with a 40V CT (center tapped) secondary. It is center tapped, and thus also labeled as 20-0-20, etc. because it has two identical 20V secondary windings, which when wired in series (the two inner terminals connected = - of secondary #1 tied to the + of secondary #2) yield an equivalent single 40V secondary with a tap in the middle that can function as 0V aka ground. Digikey, mouser, and the manufacturers that they distribute list this in a number of ways but it all means the same thing. Some variations are 2x20V, 20V parallel, 40V CT, and so on... And to add to the confusion, there are also mains transformers with only one 40V secondary winding that has a third lead which is actually connected to the center, hence center tapped. This will work the same.

Also, in case you missed this page in the Meta.

 

[blakbeltjonez]

[quote author="tmbg"]What about these?

http://www.jlmaudio.com/JLM%20Power%20Supply.htm

I think I want to order some of those![/quote]

that looks really cool, but for me it's overkill..... by the time i added a transformer i'd be over the $60 U.S. mark, and with Keith's PSU i could build it for half that. i'm just powering 2-4 Neotek modules, prolly only 100mA draw from each.

 

[blakbeltjonez]

i did miss that diagram in the meta - but your explanation made things even clearer. thanks again, Hoof.....


[quote author="Family Hoof"][quote author="blakbeltjonez"]the transformer that's listed in keith's PSU is a 20v-0-20v transformer - but nothing's listed like that on the Mouser site. unfortunately i am transformer illiterate, hence the FNG questions... so:[/quote]
Keith's (aka SSL Tech) supply calls for a mains transformer with a 40V CT (center tapped) secondary. It is center tapped, and thus also labeled as 20-0-20, etc. because it has two identical 20V secondary windings, which when wired in series (the two inner terminals connected = - of secondary #1 tied to the + of secondary #2) yield an equivalent single 40V secondary with a tap in the middle that can function as 0V aka ground. Digikey, mouser, and the manufacturers that they distribute list this in a number of ways but it all means the same thing. Some variations are 2x20V, 20V parallel, 40V CT, and so on...

Also, in case you missed this page in the Meta.[/quote]

 

[Flatpicker]

Digi-Key has 22-0-22 toroidals in several VA sizes for not much $. One of those will work just fine.