a good power supply?

[vince]

Hey everyone,

I'm presently building a pedalboard, and I would like to build the power supply circuit to supply a few pedals. Total amp. = about 200 mA.
Does anyone know a good design, with good regulation and minimum ripple ? I need something good quality like the wall wart adapter BOSS sells...

Thanks in advance
Vincent

[Rick]

Just do a search on 7809 regulator supplies and you will find. Very easy build, you have only xfrmr to small bridge rectifier to regulator and some filter caps, that's it.

[vince]

You are right, the design with the 7809 regulator is very simple.
I am thinking of buying the Small Bear 200 kit instead though. Much less trouble, and around here, only the parts would cost the price  he sells it.
There's the spyder design too. But.. is it really worth it to power individually each effects pedal?? I'm wondering how much noise I will get if I power them all off the same PS. The effects will all be very close to each other in my small pedalboard (approx. 6 pedals).

Another question though:
I have a few DOD and BOSS pedals. Some of them use positive tip and others have negative tip supply. Just to make sure, they are still negative ground pedals, right? The way I see it is that the supply wires comes in the effect differently. I just want to know if I can power them from the same supply, with the proper connections.

Thanks!
Vincent

[rooster18]

You are right, the design with the 7809 regulator is very simple.
I am thinking of buying the Small Bear 200 kit instead though. Much less trouble, and around here, only the parts would cost the price  he sells it.
There's the spyder design too. But.. is it really worth it to power individually each effects pedal?? I'm wondering how much noise I will get if I power them all off the same PS. The effects will all be very close to each other in my small pedalboard (approx. 6 pedals).

Another question though:
I have a few DOD and BOSS pedals. Some of them use positive tip and others have negative tip supply. Just to make sure, they are still negative ground pedals, right? The way I see it is that the supply wires comes in the effect differently. I just want to know if I can power them from the same supply, with the proper connections.

Thanks!
Vincent

I use the little transformers that Mouser sells from Tamura, they're about $3 each. I use a small bridge rectifier, and a 7809 (7909 for the Fuzz Face) and power each unit individually. On my pedalboard, the power supply goes under the deck, and I can add circuits as needed. It's absolutely worth having isolated power grounds. Especially if you run any gain at all on your amp.

My opinion, but it beats the crap out of any supply on the market.

rooster.

[momiel]

Another question though:
I have a few DOD and BOSS pedals. Some of them use positive tip and others have negative tip supply. Just to make sure, they are still negative ground pedals, right? The way I see it is that the supply wires comes in the effect differently. I just want to know if I can power them from the same supply, with the proper connections.

Thanks!
Vincent

Sure. Always negative ground, just like the Rat and a lot of EH stuff...

[R.G.]

Kewl. It's time for a new season of fresh recruits.

For power supplies, go read "Power supplies basics" at GEOhttp://www.geofex.com

While you're there, read about "The Spyder" and the dead battery faking power supply.

Might as well read the rest of it and answer the next seven questions, too.

Welcome.

Oh, almost forgot:

I use the little transformers that Mouser sells from Tamura, they're about $3 each. I use a small bridge rectifier, and a 7809 (7909 for the Fuzz Face) and power each unit individually. On my pedalboard, the power supply goes under the deck, and I can add circuits as needed. It's absolutely worth having isolated power grounds. Especially if you run any gain at all on your amp.

My opinion, but it beats the crap out of any supply on the market.

A transformer, bridge rectifier, filter cap and 7809 is what's in almost all the power supplies on the market.

[rooster18]

Kewl. It's time for a new season of fresh recruits.

For power supplies, go read "Power supplies basics" at GEOhttp://www.geofex.com

While you're there, read about "The Spyder" and the dead battery faking power supply.

Might as well read the rest of it and answer the next seven questions, too.

Welcome.

Oh, almost forgot:

I use the little transformers that Mouser sells from Tamura, they're about $3 each. I use a small bridge rectifier, and a 7809 (7909 for the Fuzz Face) and power each unit individually. On my pedalboard, the power supply goes under the deck, and I can add circuits as needed. It's absolutely worth having isolated power grounds. Especially if you run any gain at all on your amp.

My opinion, but it beats the crap out of any supply on the market.

A transformer, bridge rectifier, filter cap and 7809 is what's in almost all the power supplies on the market.

Well, yeah. I meant the individual transformer thing. And, FWIW, I got the idea for it from your GEO site with your Spyder circuit. In fact, it pretty much IS your Spyder circuit. The only diff is the enclosure, and I got that idea from you. In fact, the reason I have the FX setup that I do is due to you and Craig Anderton (who started me off 20 years ago on this).

So there.

rooster.

Oh, and BTW, for anyone else reading this, that site is THE resource for understanding you CryBaby and Univibe boxes. That's where I got the idea for a Leslie simulator, which hopefully, I'll be able to do at some point. Next project is the Tube-O-Vibe from Scott Swartz; that has GOT to be the best sounding phase shifter/vibrato I've ever heard.

[vince]

I use the little transformers that Mouser sells from Tamura, they're about $3 each. I use a small bridge rectifier, and a 7809 (7909 for the Fuzz Face) and power each unit individually. On my pedalboard, the power supply goes under the deck, and I can add circuits as needed. It's absolutely worth having isolated power grounds.

Great. They're pretty cheap. I also plan to have an elevated stage for my second row of pedals, so I could easily borrow the idea from you and add as many power supplies as  I need 

[vince]

Kewl. It's time for a new season of fresh recruits.

For power supplies, go read "Power supplies basics" at GEOhttp://www.geofex.com

While you're there, read about "The Spyder" and the dead battery faking power supply.

You're funny!  I'm not exactly a newbie because I'm at my last semester in electrical engineering! Although we didn't study electronics very much and I don't know much about effects ! Thanks for the link though. Your site has great stuff. I am thinking of building something like the Spyder.

[R.G.]

Small Bear has a transformer explicitly intended for something like the Spyder for about $15. Doesn't make sense to wind your own with that available.

[vince]

Small Bear has a transformer explicitly intended for something like the Spyder for about $15. Doesn't make sense to wind your own with that available.

I agree with you. I would never think about winding my own...
I meant that I will build a power supply with one supply per pedal (like the Spyder).

[R.G.]

I would never think about winding my own...

ACK! I view that attitude as morally WRONG!! 

We should always think about doing WHATEVER ourselves, then intelligently discard it when it makes sense.

I, for instance, know how to chip knives, axes and arrowheads out of stones, and which stones to look for to do this. I'd never use a flint pocketknife - if I had the choice. It makes me feel better knowing that if I didn't have a choice, I know.

Like I always say, a monstrous mind is a toy forever. 

[vince]

ACK! I view that attitude as morally WRONG!! 

Don't get me wrong. I built a wind generator a few years ago and I wound the 10 coils myself.
But for 15$, the transformer with 8 secondaries is definitely the best option for what I intend to do 

On another note,
What would be the best option to mount the circuit on ? Do you know of any cheap place where you can send them the PCB layout and they will produce if for you?
Did you use a PCB or Perfboard, for the PS setup shown at GEO for the Spyder (with 8 little transformers) ?

Thanks again and sorry for my English, I am a native French speaker

[jakenold]

I would never think about winding my own...

ACK! I view that attitude as morally WRONG!! 

We should always think about doing WHATEVER ourselves, then intelligently discard it when it makes sense.

I, for instance, know how to chip knives, axes and arrowheads out of stones, and which stones to look for to do this. I'd never use a flint pocketknife - if I had the choice. It makes me feel better knowing that if I didn't have a choice, I know.

Like I always say, a monstrous mind is a toy forever. 

Oh my god... If there wasn't such a long distance between Denmark and the states, I'd invite you over to watch my newly acquired MacGyver DVD's ASAP! Seems like we have a common interest! 

[vince]

Hey guys

I am still working on that power supply. It's coming along really good. I got the parts last week and I'm mostly done with the Trax file. Just wondering one thing though, do I have to wire the Neg. diode bridge pin to the chassis??
See schematic:


I'm not sure if it's needed or not. I guess if I don't, the reference voltage will be floating, right?

Thanks!
Vincent

[vince]

Bump

[Paul Perry (Frostwave)]

The various sections earth when you connnect the power out to whatever it is driving.
That's the whole point of all these independant supplies, they can drive positive or negative earth gear without worrying about what you are doing.

[moody07747]

Hey everyone,

I'm presently building a pedal board, and I would like to build the power supply circuit to supply a few pedals. Total amp. = about 200 mA.
Does anyone know a good design, with good regulation and minimum ripple ? I need something good quality like the wall wart adapter BOSS sells...

Thanks in advance
Vincent

well you could get that boss plug and use a daisy chain to jump from pedal to pedal or you could build a power unit like i did.

http://s2.photobucket.com/albums/y22/moody07747/Projects/9V%20Pedalboard%20Power%20Unit/

it will pump out around 1.5" before the VR chip heats and cuts out for safety.

I went with this circuit and its working great for me:

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=77&Itemid=106

I'm only using 1 of the 10 outlets now but have had 5 things plugged into the circuit at one time before.
It's nice to have the ten outlets but I don't think I'll ever get past 5 FX plugged into that unit at one time on my board.
the magicstomp runs at 12VAC, the EX7 digitech at 9VAC.  The only thing I need to power at 9Vdc right now is the RC2 looper I'm using.

[vince]

Just a quick update on the outcome of my project. I finished it yesterday.
I used a wall stud to build the enclosure and etched my own PCB (for the first time). Here are a few shots

Here is the PCB with the components


And the enclosure
Front Panel


Back Panel


Thanks to you all for the help you provided
Vincent

[Mark Hammer]

Whew.  I admire your determination and diligence, Vince, but was it necessary?  Not sure about that one.

The thing about power supplies is that it is a good thing to keep the transformer far away from the signal path...but the rectification and regulation can take place anywhere you want.  And, while in the world of high-end 50W/channel Class A audiophile amplification it is often a good thing to have things like individual transformers for each channel of a power amp, in the world of 5ma-here-1-ma-there pedal power the extra insurance that separate transformers provides is often a bit like have a million dollar policy on a pack of toothpicks.  In most instances, a simple daisy-chain power cable off one single puny wallwart is more than sufficient.  Especially if the pedals themselves have some extra power-supply smoothing internally.

Let me stress the word "often" at this point, and note that how often will depend in part on your penchant for digital effects and how the industry itself moves in that direction.  As more and more pedals become digital current-hogs, there is sometimes a need to have better isolation between pedals.  In some instances, running two digital pedals off one daisy chain has prompted reports of noise.  Not always, but sometimes.  And in those cases, a simple separate transformer may be the solution.  On the other hand, there are many options in between entirely separate PSUs for every pedal, whether digital or analog, and a simple daisy chain.  F'rinstance, paralleled regulators with their own individual outputs fed off a common transformer can provide all the isolation you may need.

Personally, what I like is a single remote AC wallwart (I have a couple of 9VAC/1.2A units I picked up for $5@) that feeds a power distribution block (PDB).  The PDB has the regulation inside it - as much or as little as you need/want for the application - as well as a status LED to let me know if there is power, and assorted jacks for running power patch cords between the PDB and pedals.  As RG suggests, it can also include differential powering, like multiple voltages, single AND bipolar, and/or starved supplies of various types.  With no transformer in the PDB itself, you can pack everything you need into a wee plastic 1590B-sized box in the corner of the pedal-board.  The AC wallwart plugs into the PDB, and when you're done, you unplug the wallwart and roll up its cord.  Meanwhile, the PDB remains in place.  This is, in fact, no different than what you have there (and I compliment you on the convenience and usability).  The major difference is one of cost, size, and immunity to EMI.

The EMI thing, can be an issue or a nonissue.  If you have a big pedalboard, with lots of room between pedals and PSU, a metal PSU chassis, metal shielded pedals, and patch cables with decent shielding, EMI concerns may be moot.  If you have a cramped pedalboard, modest quality patch cables, plastic Behringer or Danelectro pedals (or equivalent) on your pedalboard, etc etc., then there may be some legitimate concerns about keeping power transformers as far away as possible...in which case the AC t scenario I describe works out better.

Again, not all pedalboards and circumstances are the same.  What you've shown is clearly a Rolls-Royce solution.  Some of us, though, only drive to the corner store and back every now and then.  I just wanted to let people know that there was something in between the Rolls-Royce solution and nothing; the 2nd hand 1998 Corolla solution.

Some will note that I have completely omitted ground loops and the role of PSUs in that.  Guilty as charged.  As the electronic landscape moves ever onward, though, the sources of hum and power-line noise will change.  As I've noted, many jurisdictions are moving towards fluorescent-only lighting, and that will pose a source of hum perhaps even greater than what underdesigned PSUs will pose.  We'll see when we get there.  I just hope we see an emergent industry of shielded fluorescent fictures.  Particularly the industrial/institutional fluorescent fixtures many of us work with.  But that's fodder for another thread.