Power Supply Input for Effects

[modsquad]

Weird thing going on.  I have a wall wort putting out 9v and 1700ma.  When I plug my DIY stuff into it, they power up and work fine.  I have an EVH Phase 90 and an Orange Phase 90 that when I plug them into it they hardly power up and all I get is a ticking sound.  However the weird part is that with a 9v battery in them they work fine.  So what's the deal is there a problem with the current that the chips in the Phasers have a problem with?

[Processaurus]

Those heavy current switching power supplies are weird, they can get into a state of continually starting up and shutting down if there isn't a certain minimum current draw.  I've seen that happen with some pedals, the LED will just sort of blink.  Solution is to daisy chain more stuff on there, or put a dummy load in the pedal so it sucks more current.

Either that or something's shorting out your power supply when you plug them in.

[modsquad]

Funny thing is its  both the MXR phasers that have the problem.

[GibsonGM]

That tells you something...might have to do with the current draw of the MXR's.  If you tweak them to up the draw, remember that it will also do that to your 9V battery if you return to using one!   
Better off just finding a good power supply designed for pedals (or build one!) 

Remember, a circuit will only "take" current - the PS doesn't "force" anything into it.  Larger PSU's require a minimum draw to get to the right voltage output and to switch correctly.  The voltage output (unregulated) is not actually the 9V listed until you approach the rating.   This has happened to me, trying to use an unregulated 9V/200mA supply that's actually putting out 15V!  It only is at 9v with the 200mA applied, and my pedal pulled 5mA....likely, your MXR stuff is very low-current, too. 

1.7A is an awful large 'reserve', and I agree that there just might not be enough draw to switch it correctly.  Could've been a good thing, depending on how sensitive the MXR's are (ZAPPP  blue smoke maybe).
 

[R.G.]

Those heavy current switching power supplies are weird, they can get into a state of continually starting up and shutting down if there isn't a certain minimum current draw.  I've seen that happen with some pedals, the LED will just sort of blink.  Solution is to daisy chain more stuff on there, or put a dummy load in the pedal so it sucks more current.

That startup/shutdown behavior is part of the protection setup. They start up and the output voltage is either too high or two low to be good, and the circuit can't make it right within a few milliseconds. So they are designed to shut down and try again. This doesn't run things very well, but it doesn't burn them out either.

Either that or something's shorting out your power supply when you plug them in.

That is a highly likely possibility. When run into a short or any load over their maximum, they are designed to stop supplying current, and try to restart. Again, it's nondestructive. I would check the wiring on the DC input jacks carefully. Or do both pedals work OK with other adapters? The DC jack switches when something is plugged in. It's possible it shorts the DC plug, maybe.

Funny thing is its  both the MXR phasers that have the problem.

Once is an accident. Twice is coincidence. Three times is enemy action. I would consider it more likely that two pedals from the same manufacturer would act alike. They have the same heritage.

Better off just finding a good power supply designed for pedals (or build one!)

Good point. But there are two adapters marketed for pedals with that rating that I know of - the 1Spot and the Power-All.

I don't know about the Power-All, but the 1Spot is designed for operation with pedals. The 1Spot is stable with loads down to zero and up to the full 1.7A, and is tested to be so. We have the occasional 1Spot which ticks with normal pedals which are not faulty,  but those are clearly defective and are replaced if still under warranty.

[MartyMart]

"Gigrig" also make a 9v 5amp pedal PSU : http://www.thegigrig.com/acatalog/The_GigRig_Products_UK.html
Probably all you'll ever need - £79 though.
Two friends of mine use them, one is Rob Harris who plays for Jamiraqui.
MM

[GibsonGM]

Right, but Modsquad didn't specify if his wart was designed for use with low current circuits (regulated), or just something he found lying around with the same polarity.  Always hit or miss with those things!! 

A 5AMP PSU for effects, Marty? Holy cow!   

[Processaurus]

I don't know about the Power-All, but the 1Spot is designed for operation with pedals. The 1Spot is stable with loads down to zero and up to the full 1.7A, and is tested to be so. We have the occasional 1Spot which ticks with normal pedals which are not faulty,  but those are clearly defective and are replaced if still under warranty.

A friend using a great cheddar clone of mine (4.5mA draw) had the "tick" using a VS one spot he "found in the van".  I'll let him know its defective.  Think its unsafe to use with heavier draw effects?

[R.G.]

A friend using a great cheddar clone of mine (4.5mA draw) had the "tick" using a VS one spot he "found in the van".  I'll let him know its defective.  Think its unsafe to use with heavier draw effects?

It's almost certainly not unsafe to use with heavier draw effects. In fact, chances are good that it will work fine with heavier loads.

The ticking restart is a nonspecific flaw. On all switching power supplies, there must be some minimum load, or the output would go overvoltage. Good design practice dictates that you put this minimum load inside the power supply itself and make it as small as possible. Mother Nature being the lady that she is, sometimes the tolerances don't add up the right way and you just barely miss the minimum. Or a resistor value drifts, or ... well, you see where that goes.

If it's still under warranty take it to a dealer and get another one, or send it in for warranty claim.

If it's an older unit that the warranty has expired on, and he "found in the van" it may already have had a hard life. But there is hope. I suggest that you try it with a heavier load, maybe two or three pedals. It may be that the ticking goes away at modest loads like two or three pedals. If so, it's fine to use up to its full spec. We don't get many defective units back, but of those that we do get back, some of them act like this.

If it still ticks with modest loads, it's still not likely to be unsafe in the sense of hurting your or your pedals. But if the ticking subsides with bigger loads, it's probably fine to use it that way.

[Processaurus]

Thanks RG!  Great to know, those are handy to have around.

I was a little jealous, all I find in our van are 6 month old leftovers   

[modsquad]

Wow excellent stuff guys.   I neglected to say that the PSU is designed for pedals it has a daisy chained jack chord with about 5 outputs on it.  In fact I just looked at it and its a 1-Spot.