Not all 9V power supplies are created equal. What specs should I be looking for?

[fingerace]

I was looking for a 9 volt dc power supply to run my pedals on. I went to the local electronics shop and got one with enough current to power all the pedals at once. It's also "Regulated". I also got a splitter for 8, and I was all set.

It's so noisy! When the amp is at low levels, you can't really tell, but once cranked up - unbearable. I tested everything in the signal chain, it's the power supply.

So the question is, why is it noisy? Is there something in the specs that I should be looking at?

Thanks

 

[bancika]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

you want isolated supply where each output is independent, like voodoo lab iso 5 or similar. Otherwise, you may get ground loop noise. With daisy chain (non-isolated) supplies, all outputs share the same ground and your pedals also share ground through jumper cables which causes ground loop.

 

[fingerace]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

you want isolated supply where each output is independent, like voodoo lab iso 5 or similar. Otherwise, you may get ground loop noise. With daisy chain (non-isolated) supplies, all outputs share the same ground and your pedals also share ground through jumper cables which causes ground loop.

Thank you very much for the explanation. I am looking it up on google, but if you have any links explaining what's going on with this ground loop business, they would be greatly appreciated.

Is there any way to fix this when running a daisy chain?

 

[bancika]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

you can cut the negative lead between the first and the second output of the daisy chain, so only the first output gives ground reference to the first pedal and all other pedals get connected to ground through jumper pedals...just make sure to always connect the first output to one pedal.
Or you can go the other way round and modify each jumper cable between pedals to have ground connection desoldered (or cut) on one side.
It's useful to have one jumper cable like that at all times so you can debug noise problems, just move it between pedals until you find two that form the problematic loop.

But it's still better to have isolated outputs....imagine going out and having to drink beer together with 5 of your friends from the same large glass. It would work but is less than ideal...the same is with power supplies

Here's some article http://stinkfoot.se/archives/528

 

[fingerace]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

you can cut the negative lead between the first and the second output of the daisy chain, so only the first output gives ground reference to the first pedal and all other pedals get connected to ground through jumper pedals...just make sure to always connect the first output to one pedal.
Or you can go the other way round and modify each jumper cable between pedals to have ground connection desoldered (or cut) on one side.
It's useful to have one jumper cable like that at all times so you can debug noise problems, just move it between pedals until you find two that form the problematic loop.

But it's still better to have isolated outputs....imagine going out and having to drink beer together with 5 of your friends from the same large glass. It would work but is less than ideal...the same is with power supplies

Here's some article http://stinkfoot.se/archives/528

Thank you very much. You've been very helpful.

 

[TwilightOdyssey]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

Great, tho disgusting analogy, bancika!

 

[Little Pigbacon]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

Here's some article http://stinkfoot.se/archives/528

Good article. Thanks for the link. I never would have guessed that about the effects loop vs. in front of the amp.

 

[uOpt]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

I wish somebody would make 1/4" plugs with a built in ground lift switch. I have so many uses for that.

 

[Little Pigbacon]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

Do you get good results from lifting the ground on the signal cable? I've never tried it with guitar stuff -- just A/V, where it usually makes things worse.

 

[the guy who invented fire]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

regulated and isolated are the 2 big things you want to look for.

 

[uOpt]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

Do you get good results from lifting the ground on the signal cable? I've never tried it with guitar stuff -- just A/V, where it usually makes things worse.

I am listening to youtube on a soundlifted speaker set right now.

I think the tricky bit is that not every piece of noise is in the strict sense of the term caused by a ground loop. Most people only have a fuzzy concept of shielding, grounding, humbucking, symmetric cables, pair twisting and the like.

If a piece of noise is not from a "real" ground loop then lifting ground usually screws up the shielding even more than before.

 

[Stratman]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

I have tried several power supplies, including Dunlop DC Brick, all of the voodoo lab series, and T-Rex Fuel Tank ‘Chameleon'

While the T-Rex cost the most, it also works the best.

T-Rex has Isolated output, regulated, and all necessary voltages and can handle current (Amperage) needs of pedals.

http://www.musiciansfriend.com/accessories/t-rex-engineering-fuel-tank-chameleon-power-supply :cool2:

http://www.musiciansfriend.com/accessories/t-rex-engineering-fueltank-classic-power-supply


Voodoo Labs are good, but on some if you need 18V you need to use a jumper cable.

http://www.musiciansfriend.com/accessories/voodoo-lab-pedal-power-2-power-supply

http://www.musiciansfriend.com/accessories/voodoo-lab-pedal-power-iso-5-power-supply

http://www.musiciansfriend.com/accessories/voodoo-lab-pedal-power-digital-power-supply

http://www.musiciansfriend.com/accessories/voodoo-lab-pedal-power-ac (AC unit)


Dunlop DC brick does not have isolated outputs and a funky power connection.

http://www.musiciansfriend.com/accessories/dunlop-dc-brick-multi-power-supply and rebranded unit (e.g., Same unit) http://www.musiciansfriend.com/accessories/gator-g-bus-8-us-pedal-board-power-supply


AND THEN some people like http://www.musiciansfriend.com/accessories/visual-sound-1-spot-combo-pack

 

[Little Pigbacon]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

There's also this T-Rex piece here, perhaps the baby brother.
http://www.musiciansfriend.com/accessories/t-rex-engineering-9v-fuel-tank-junior-guitar-effects-pedal-power-supply
They look like good products. The flexibility seems pretty awesome. It's nice that they take in a regular mains power cord, instead of being powered, in turn, by another wall wart.

Based on the looks alone, I'd gladly pay the extra for the Dunlop over the Gator. I just really like that fit and finish.

I use a 1-Spot myself, but that's mainly because I haven't gotten around to deciding on the "perfect" power unit like we're discussing here, and also because I haven't used the 1-Spot in enough different situations to run into issues with it yet. I'm sure I will, if I get creative enough.

 

[Stratman]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

There's also this T-Rex piece here, perhaps the baby brother.
http://www.musiciansfriend.com/acce...tank-junior-guitar-effects-pedal-power-supply
They look like good products. The flexibility seems pretty awesome. It's nice that they take in a regular mains power cord, instead of being powered, in turn, by another wall wart.

Based on the looks alone, I'd gladly pay the extra for the Dunlop over the Gator. I just really like that fit and finish.

I use a 1-Spot myself, but that's mainly because I haven't gotten around to deciding on the "perfect" power unit like we're discussing here, and also because I haven't used the 1-Spot in enough different situations to run into issues with it yet. I'm sure I will, if I get creative enough.

Dunlop and Gator are the same piece of equipment, just painted differently. I know because I have purchased both, few year ago.

Neither is an isolated power supply and both have junk power connectors.

 

[Little Pigbacon]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

Dunlop and Gator are the same piece of equipment, just painted differently. I know because I have purchased both, few year ago.

Neither is an isolated power supply and both have junk power connectors.

They might be the same on the inside, but it looks like they have completely different cases. Just saying I like the Dunlop case a lot better. But if the outputs aren't isolated and the connectors are lousy, it's a moot point. They look like 1/8" mono (3.5mm) tip/sleeve jacks. Are they? Because those usually do suck. And powering your power supply with an outboard plastic wall wart does seem to take some of the fun out of it.

Good to know there are better options.

 

[bancika]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

dunlop is nothing more than a glorified daisy chain in the box....not worth even close to what it costs. I own one and it does work OK with my 3 pedals, but hums like hell when I connect wah or portable recorder

 

[Jeff5]

Re: Not all 9V power supplies are created equal. What specs should I be looking for?

I've had the Dunlop for a long time and it is pretty noisy. I didn't use it for several years because I really didn't use pedals. With my Blackstar HT5 and set up in my study I started using pedals again and needed power so dusted it off. For my (relatively) low volumes in my study it's fine, but if I was playing even moderately loud with this set up or playing out I'd invest in a Voodoo Labs or other isolated power supply.