multi 12v power supply

[Mgt280y]

Been building some of Frequency Central tube pedals, all of which are running 12v and planning to build the murder 1 to run a small practice amp.

Are there any builds anyone has done for a 12v clean power supply multi output ideally something that could run pedals and the amp not sure if they need to be isolated outputs or not and i havent got the consumption of each of the pedals yet.

Anyone got any ideas

[antonis]

Ideally, they must be isolated..

That's the first think you have to consider 'cause something like "Spyder" (R.G. Keen at Geofex) is of totally different design from "conventional" multi-output PS..
(at least on AC part..)

[Mgt280y]

Thanks for the reply the spyder concept may just work, started drawing up schematic and board layout in eagle, thinking I will start with a basic filter setup as dead battery and adjustable isn't necessary at the min.

I'm looking at a board with 2 Block transformers 230v primary with 2 x 15v secondary then rectifying filtering and 7812 reg to give me 4 x 12v outputs so far straight forward.

Couple of design questions
I'm arranging the 230v input and neutral on the side with a symmetrical set of pads on the other side so a second board could be added, hope that makes sense lol, in terms of the trace from 230 input - tx - tx - output(optional add on board) is there a calculation or rule for the width of the trace?

Other thing is for the section after the rectifier I have drawn 4 individual ground planes (plains?) for DC section only. Does anyone disagree with this and further more should I add a top plane for any reason

Having a second pair of eyes check over all my Ac off board as not taking any risk there but on that subject what are people using for the termination of the Ac to the board and also if anyone as used anything specific for jumpering Ac from board to board as I say not taking chances with Ac.

Thanks

[antonis]

!!! MAINS HAS NO PLACE ON PCB !!! !!! MAINS HAS NO PLACE ON PCB !!! !!! MAINS HAS NO PLACE ON PCB !!!



As for ground planes, keep them individual for each 15AC secondary...

P.S.
I hope that 2 X 15 V ISN'T a 30VCT type..

[bluebunny]

!!! MAINS HAS NO PLACE ON PCB !!!

Tell that to the many manufacturers making PCB-mounted transformers.   

[antonis]

Tell that to the many manufacturers making PCB-mounted transformers.   

I can't 'cause I also use them in low current power supplies.. 

[bluebunny]

Ha ha!  Me too, but don't tell anyone...   

[Mgt280y]

It was a pcb mounted transformer that i had spotted thought it would make light work of the ac connections and no mounting of the tx needed.
altho after looking im wondering if the tx i found is going to be right as witht his type im looking realistically at around 70ma per secondary, so might need a re think half the issue is i want 230v primary anyone else used a uk spec tx

[Rixen]

PCB mount screw terminals for mains connection to PCB, but best done with plated through holes as single sided pads can let go a bit too easily.

Other options are 6.3mm tab terminals or soldering wires direct to the PCB (as is done in virtually all computer SMPS that don't have a board mounted IEC connector)

Watch the conductor separation for mains voltage- you need to allow for 2 kv spikes and there are standards available to cover this