Power Supply build

[yeeshkul]

necessary parts:
- transformer: 10VAC, primary - mains VAC, secondary - 2x 15VAC/2x330mA
- caps: electrolyte, 2x1000uF/35V, 3x10uF/25V
- diode bridge (the round type with +- on the opposite sides)
- voltage regulators (TO220 case, 1A): 7809,7815,7909
- fuse (primary side): 100mA,  slow(T) type (the value depends on what you want to feed from the supply)

optional parts for the primary(hot) side:
- PCB terminal block: to connect high voltage wires to the primary side - i find it usefull
- high voltage switch
- socket with an inbuilt fuse drawer
- heat-shrink isolation for switch and socket lugs

SCHEMATICS:


BOARD (300dpi) print it out first to check and possibly adjust the distances

[yeeshkul]

for george:

If you wanna build this one, please notice that the fuse is not a part of the board so you have to either extend the primary side of the board to add the fuse socket or get a high voltage socket with an inbuilt fuse holder.

Also:
- measure everything 10 times before you plug it in
- isolate all the hot parts
- check the orientation of all caps
- if you want to add some sort of cooler to the voltage regulators you can't connect the metal extension of the 7909 wit the others because of the different pinout (the metal piece is connected to the ground in case of 78xx UNLIKE the 79xx where the connection goes to the input lug)

[mat]

Hi yeeshkul !
Thanks for the layout for the PS 
I built similar powersupply for my multieffectbox (orange squeezer,rangemaster,FF,neovibe,drive1,drive2,rebote2,small stone,ea tremolo). Its almost ready but I was wondering if there might be a hum problem when all the effects (not talking about the rangemaster and FF=negative ground) has same ground. I mean I have read something about the neovibe project and not to use same ground as the neovibe for other effects.

mat

[yeeshkul]

Hey Mat, i did use the same ground (star grounding => all grounds, volumes etc. to one point on the output jack ground) for NV, FF and RM and there is no hum (the power source has to be separated by some sort of shield if in the same box). If i understand the idea well though - NV works with 200 times bigger current than FF or RM, which may cause some sort of parasite resistances at ground due to the fact that no conductor is perfect (=it has a miniature resistance and therefor a voltage loss). Also FF and RM have each a decoupling cap.

EDIT i asked for explaining somthing about separate grounds - not needed anymore, i've just got it

[Auke Haarsma]

Nice post, thanks for sharing!

I'm planning to build a PS like this one. I have a DIY-PS but it is too big (it's for my multi-fx project, see my sig). I currently use 3 xformers, but like to reduce it to just one.

I've read that for an even more stable supply you can use a 10 uF and a 10 nF cap in parallel. Have you considered this?

You use a x-former with 2 secondaries. And you combine the two inner-pins to form ground. In other powersupplies (see GGG) I see that the "-" after the diode-bridge is taken as ground. I've read some at wiki (http://en.wikipedia.org/wiki/Split_phase) but I don't really understand this. Could you shed some light on this?

@Mat: do you have any info/pics on your ps? I'm curious to see what you've come up with

[yeeshkul]

I've read that for an even more stable supply you can use a 10 uF and a 10 nF cap in parallel. Have you considered this?

I haven't but it sounds like a good idea to have the high frequencies sorted by smaller cap in parallel - R.G. recently stated he added a small cap that helped to prevent oscillation.

You use a x-former with 2 secondaries. And you combine the two inner-pins to form ground. In other powersupplies (see GGG) I see that the "-" after the diode-bridge is taken as ground. I've read some at wiki (http://en.wikipedia.org/wiki/Split_phase) but I don't really understand this. Could you shed some light on this?

This is symmetric power source +/- 9V taken from the output of the bridge towards the independent ground in the centre. I didn't read about supplies at GGG, i've just pulled out my old textbook and spent a few days reading it again, haha

[yeeshkul]

Funny story about this one: this was my first hi-voltage unit i've ever made so i was a quite massively nervous about burning my flat down and stuff. When i first fired the thing up - bang - complete dropout in the whole flat. Well, it was a general blackout in the whole housing-estate .. they were repairing something ... at the very second i turned my first hi-voltage unit on for the first time.   

[Auke Haarsma]

LOL

And thanks for explaining. Seems I need to do some further reading

[mat]

@Mat: do you have any info/pics on your ps? I'm curious to see what you've come up with

Actually I built my PS exactly as the yeeshkuls layout shows. Transformer is 2x15V toroid. I'll fire the PS next week - will report back how it went.

Matti T.

[rogeryu_ph]

I think the 24V is not regulated isn't it? They also recommend to use diode protection for IC regulator.  Nice clean built there yeeshkul.

Roger

[yeeshkul]

it is not regulated and i think that it is 19.7V really 15(rms)x1.4(to get peak after the filtering cap) - 1.3V(voltage drop on the bridge)

[yeeshkul]

Also, i feed Neovibe, FF and RM from this, all of them in one box. There can be a noise issue if you leave the bulb pumping when Neovibe is bypassed - use 3PDT switch and cancel(see the explanation below) LFO with the 2 spare 3PDT pins. You can still have LED attached - coming right out of the circuit with a resistor in parallel:



Then -  when NV is off LED is on (= power is on), when NV is on LED is pulsing.

[yeeshkul]

Sorry i used the word "cancel" - that may be missleading - using the cancel switch would not help here, you have to lower the intensity to minimum when Nevibe is turned off. Just connect the 2 spare pins on 3PDT to the intensity pot the way that 3PDT will shorten the pot lugs hereby lowering the intensity to its minimum -> no noise.

[petemoore]

you have to lower the intensity to minimum when Nevibe is turned off. Just connect the 2 spare pins on 3PDT to the intensity pot the way that 3PDT will shorten the pot lugs hereby lowering the intensity to its minimum -> no noise.
  Good think through achieved the goal !