GGG Regulated Power Supply questions

[ConanB]

I'm wanting to build a power supply for my pedals to save me buying batteries all the time and was looking at the Regulated Power Supply listed on General Guitar Gadgets.

Since I'm still new to electronics and living in Australia I was looking around at different transformers to use but wasn't sure which would be best to replace the Flat Pack transformer listed in the design (http://www.generalguitargadgets.com/pdf/ggg_reg_power_supply.pdf)

I've been looking at ones from Altronics and Jaycar. Any of these fitting replacements?

http://www.altronics.com.au/index.asp?area=item&id=M2852L

http://www.jaycar.com.au/productView.asp?ID=MF1212&CATID=&keywords=MF1212&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

http://www.jaycar.com.au/productView.asp?ID=MM2006&CATID=19&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=411

Should I be looking at a different model perhaps?

I understand some of how the transformer works and how to wire it up so hopefully will be all ok there.
But I'm still a little iffy about how to wire up the ground for this one, so it'll be slow and steady going with this. Don't want to give myself a harsh zap now do I

Any tips, suggestions, websites on hooking up a simple transformer for a 240v input would be greatly appreciated!

Cheers,
Conan.

[miqbal]

Hi Conan,

The link from altronics and the second one from jaycar should work for the GGG layout. If you want to fully utilize the 7809, look for a 1Ampere (maximum) transformer. To make it a lot easier, look for a transformer with no CT.

[ConanB]

Do you mean something more like this?

http://www.jaycar.com.au/productView.asp?ID=MM2002&CATID=19&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=411

I also found this listed; not 1Ampere, but is it similar to the original design?

http://www.altronics.com.au/index.asp?area=item&id=M7024

[miqbal]

Do you mean something more like this?

http://www.jaycar.com.au/productView.asp?ID=MM2002&CATID=19&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=411

yeah, thats better, but you have to carefully use ONLY the 15V connector, since the current at the other connector is higher than 1Ampere.

I also found this listed; not 1Ampere, but is it similar to the original design?

http://www.altronics.com.au/index.asp?area=item&id=M7024

I don't know for sure, but I think if you follow the GGG layout using the transformer from Altronic,  the transformer will be wired in series, hence lower ampere/current. You have to re-layout the GGG's a bit to wire the transformer in parallel.

[ConanB]

yeah, thats better, but you have to carefully use ONLY the 15V connector, since the current at the other connector is higher than 1Ampere.

Not totally sure what you mean there; do you mean I only hook up one of the secondaries?

I don't know for sure, but I think if you follow the GGG layout using the transformer from Altronic,  the transformer will be wired in series, hence lower ampere/current. You have to re-layout the GGG's a bit to wire the transformer in parallel.

I was planning on using vero as I haven't attempted to etch my own PCBs yet, so layout shouldn't be a problem.
So that PCB Altronic transformer could work if it was just wired parallel?

I guess I'd probably prefer to go with the 15v 1Ampere one if I can understand how to hook it up.

My goal is just a power supply that could power up to 10 or so 9v pedals, so whatever layout/design I need to go with is what I'll do, and this one seems like what I'm after.
I have all the parts I need for this, just no transformer 

[miqbal]

Not totally sure what you mean there; do you mean I only hook up one of the secondaries?

Yes. If I was not misreading the explanation about that transformer on the link given (a datasheet is always better), It has six output (6.3V to 15V), i.e, it has seven solder lugs on the secondary, including the 0 Volt lug. It means you can choose the output of the secondary. The lower the voltage you choose, the higher the available current will be.

I was planning on using vero as I haven't attempted to etch my own PCBs yet, so layout shouldn't be a problem.
So that PCB Altronic transformer could work if it was just wired parallel?

It will work perfectly either in series or parallel or just one winding. The current/wattage will be doubled if you wired it in parallel. If you wired it in series, I think (sorry, I'm not quite sure about this ) the voltage will be doubled but the current will be half of the paralled one.

My goal is just a power supply that could power up to 10 or so 9v pedals, so whatever layout/design I need to go with is what I'll do, and this one seems like what I'm after.

Ok, I assume you will use the power supply to drive your solid-state stompboxes (i.e,no tube, like Boss MT-2, Ibanez TS-9, DOD, etc).
Let's take 50mA as an average value for the amount of current drawn by a stompbox. If you have a power supply with 500mA transformer, it means the power suplly can drive 500mA/50mA=10 stompboxes. If it was a 1 Ampere power supply, roughly it can drive up to 20 stompboxes. It's that simple.

But remember, the calculation was taken from an average value. Actually, the amount of current drawn will vary from approximately 4mA to 350mA.

EDIT:
Please have a look at this CURRENT CONSUMPTION TABLE below (I hope the data is still valid, though).

http://www.cioks.com/assets/CURRENT%20CONSUMPTION%20TABLE.pdf

[ConanB]

Thanks for all that! Its all definetely helped.

I think Ill probably go grab the 15v transformer when I can and try to get this thing going (heres hoping I dont zap myself in the process )

The pedals I have built and plan to build are all solid-state, but I guess sometime in the future I'll probably mess with a tube pedal, but I'll worry about it's power when I get to it

Do you know of any online resources for wiring transformers correctly? I've been searching around and have a basic understanding, but still a little unsure about the primary wiring etc

[miqbal]

I've been searching around too, but can't find any that suitable for you. I think it's not surprising considering the wide variants of transformers: CT and no CT, one/two/three primary/secondary winding, series/parallel capability, step up/step down, etc.

But I think the one from jaycar is not that complicated.  One primary winding (240V), six secondary (6.3-15V), no CT, that's all

[ConanB]

I asked around at work if anyone had done any electronics engineering before and was surprised to find one former electrician, and one former large scale electrical engineer.
They were able to put me straight on mains wiring and hooking up the transformer for a 240v environment so I should be fine.

Thanks for the help and suggestion on the 15v! I now know what it is I'm doing so the chance of killing myself is far less than it was before

[jakenold]

Look for something that from the datasheet will fit the board - that'll be the easiest, unless you are doing it on perf.

Whether less or more than 1A; a smaller transformer will be the bottleneck if you are drawing a lot of power and the regulator can handle it, but the regulator will be the bottleneck if your transformer can supply more than 1A. But that's not a problem at all!

How much power you need translates to which effects you'll hook up. If you get a 9-12V 9-12VA (Volt x Ampere) transformer, you can power at least 12 of the analog projects on these pages.

Jake

[ConanB]

Yep I pretty much understand transformers now so I should be ok.

Will be using the 15v 1Ampere transformer and will be making sure the regulator has sufficient cooling on it (may even use a tiny 30mm PC fan over it).

Will throw this all together when I get the chance and hopefully I wont need to waste any more money on batteries. Hooray!