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Daisy chain related questions

O

ourworldisgrey

Jan 7, 2009
262
2
South Jersey
#1
I recently got a one spot daisy chain, but not the actual power adapter, and have been using the adapter from my opto stomp, and I have been getting a really large amount of hum from my pedalboard. Everything still lights up fine, but there is a really annoying level of hum. I checked the adapter and it is 200 mA 9v. I am powering between 3 and 5 pedals (I'm still working out my chain). I looked up specs of a one spot adapter and it supplies 1700mA, and I couldn't find a voltage rating, but I'm assuming 9v(correct me if I'm wrong).

Now my questions:

Will switching to a one spot power adapter eliminate hum problems? I don't even think my board uses 100mA (only digital pedal being a tuner).

Will using a 200 mA adapter cause any damage to any of my pedals?
 
#4
Power supplies intended for single pedals are often "unregulated". I'm not really sure what this means in technical terms, but I know it means "more likely to hum with a daisy chain". 1spots are regulated, and so yes, are less likely to hum. Nothing is guaranteed of course, but much less likely.

I've powered up to 15 pedals off one 1spot with no hum problems, running to multiple amps in a church building where the monitors usually pick up AM radio and ground loops are an everyday occurrence. So as far as I'm concerned, 1spot is very unlikely to hum.

Steve
 
#5
That is interesting Steve, I had never thought about unregulated/ regulated power supplies causing problems. That does make alot of sense though.

Would anyone know if using my adapter would cause any damage to my pedals? I really doubt it, the worst thing, as I understand it, that could happen is the pedal won't have enough juice to turn on.
 
#6
It is likely that you're under-powering your pedals, causing distortion. It is also likely that one or more of your pedals is center positive ground (most pedals are center negative). It could also be that you have a ground loop or a faulty cable. Unregulated means that the voltage and mA output would fluctuate, especially the more pedals you connected to the supply. That could also be a reason for the hum.

I'd say trying a 1-Spot or a Godlyke Power-All first. That BBE power supply wasn't meant to be daisy chained.
 
#8
SteveMcB said:
Power supplies intended for single pedals are often "unregulated".
Click to expand...

Not anymore - most power supplies nowadays, even for single pedals, ARE regulated. Take Boss, for example - you'd have to look back to some of their ancient pedals like the DM-2 to find an ACA adapter (which was unregulated) required. They've all used PSA adapters (which ARE regulated) for nearly two decades.

Exceptions exist, but your typical effect pedal power supply is regulated. I'm 99% sure his BBE supply is regulated, because that's what the pedal calls for.

ourworldisgrey said:
Would anyone know if using my adapter would cause any damage to my pedals? I really doubt it, the worst thing, as I understand it, that could happen is the pedal won't have enough juice to turn on.
Click to expand...

Actually, if you run a pedal at less voltage than it requires, it's harmless (hence, why some specialized power supplies offer "dying battery" simulators which simply turn down the output voltage). But running it with a power supply that can't supply enough current CAN harm something. The power supply could burn out, and other problems could arise. Some pedals will simply not function when they don't have enough current, but others might actually try to push the limits of the supply.

So, let's get to the source of the problem by answering a few questions first, rather than speculating to no productive end. ;)

Now, you say you're getting hum. My first step would be to ensure that I'm not demanding more current than my power supply can provide. My second step would be to see if any of my pedals are prone to causing hum problems when daisy-chained. Both of these steps require that I know what the pedals are... so what's in your chain when it hums? Does it hum when only one pedal is on, or when several are turned on?
 
#9
MysticBoo said:
Both of these steps require that I know what the pedals are... so what's in your chain when it hums? Does it hum when only one pedal is on, or when several are turned on?
Click to expand...

My chain is opto stomp > modded ts9dx >modded proco rat > fender tuner. Sometimes I add a stereo electric mistress or a rocktron hush (which actually adds noise when on, which is doesn't do at all when used on my big powered skb board, I don't use the skb becuase its huge and really overkill for what I want/ need for bass).

It hums when anything is on.

I don't think I'm going over the current limit of my power supply, unless there is some kind of headroom needed.
 
#10
Hmm...

I know the Mistress is digital, but I'm not sure of its usage. With that exception, your other pedals do not add up to more than 200mA. Additionally, you only pull more current with each pedal that's turned on... so if only one or two pedals are on at a time, there shouldn't be an issue as far as current is concerned. That rules out lack of current as a culprit.

As far as polarity, I don't see any problems either. But you did mention two pedals are modded... maybe there's a ground or power jack issue somewhere?

If it is indeed humming regardless of what's turned on... that's actually fairly odd. Transformer-based power supplies (like your standard wall wart) are known for being less noisy than switch-mode supplies like the Visual Sound 1 Spot or Godlyke Powerall.

Perhaps there's something wrong with the adapter itself. Try plugging it in directly to just one pedal. Try the Mistress first, because I know that one has no known problems of that kind. If you're still getting the noise, then try plugging the adapter into another wall outlet in your room. Turn off any fluorescent lights in your room.

And lastly... what about your bass? Your gain pedals will contribute to and amplify any noise already in the chain. If you're running a bass with single-coil pickups of some kind (i.e., Jazz basses), you can expect hum, and it will be amplified by gain pedals.
 
#11
So reading this, I am having the same issue with a 9v 1300mah output until I checked it and saw that it was not regulated (clean it was putting out 13.2v, smooth)

So when I've been looking online, I see that a lot of pedal power supplies are 90+ and the 1 spot ranks in at $20, is there a real reason to get a bigger pedal power supply?
 
#12
Yes, there is, but not for the average musician. Most people are using ordinary pedals that run off of "Boss standard" supplies... in other words, regulated 9VDC, 2.1mm barrel plug, center-negative. The nickname comes from the fact that those are the exact specs of the modern Boss PSA series wall wart, which is what most Boss pedals use. Any decent supply which meets these specs (which happens to be almost all of them) will work.

The more expensive supplies are for those of us who run into uncommon problems or are trying to power pedals with odd requirements. Let's take my case, for example. One of my pedals, an MXR Blowtorch, uses an 18VDC supply. I need an 18VDC source. Rather than use a separate adapter, I use the Voodoo Lab Pedal Power 2+, which will take care of that with a special Y-cable and still power my 9VDC pedals with ease.

The important distinction to watch out for in shopping for an expensive power supply is whether its outputs are "isolated." Isolated outputs allow you to avoid some of the pitfalls of daisy chains by electrically treating each output as if it were an individual wall wart. If your "problem" pedal uses PNP transistors (creating a "positive" ground), has a weird design which creates a lot of noise on daisy chains (such as most Line 6 pedals), or requires a voltage other than 9VDC, then having isolated outputs to work with on your supply is essential.

Mid-priced supplies like the Dunlop DC Brick don't have isolated outputs, but they do offer other perks (like 9VDC and 18VDC outputs, in the case of the Brick).

But if you have nothing out of the ordinary in your chain, then I wouldn't go nuts on your supply. Most musicians will not benefit from the expense unless their circumstances call for it.
 
#13
One pedal plugged into the adapter by itself is fine, even the mistress which I thought might be a culprit because of its weird power needs (MysticBoo thanks for your review, it helped me deciede to get a SEM),but with the daisy chain it gets real bad, even with nothing turned on.

As for the mods, I used the ts9dx and the rat on my powered skb board I use for guitar(I don't use it for bass becuase its huge and I don't want to carry that around for 5 pedals at the max) and it is not very noisy. I can't speak for what was done to the ts9dx, but the rat was just an IC and some diodes getting swapped, and some resistors switched for pots.

My bass is a fender jazz which is not particularly noisy by itself, or just with a comp and tuner, which is what I used to use before I got into effects (comp powered with the supply, tuner with batteries)
 
#14
TheMutt said:
It is likely that you're under-powering your pedals, causing distortion. It is also likely that one or more of your pedals is center positive ground (most pedals are center negative). It could also be that you have a ground loop or a faulty cable. Unregulated means that the voltage and mA output would fluctuate, especially the more pedals you connected to the supply. That could also be a reason for the hum.

I'd say trying a 1-Spot or a Godlyke Power-All first. That BBE power supply wasn't meant to be daisy chained.
Click to expand...

In an unregulated supply, usually all you have is a transformer applying what ever voltage it is wound for. In a regulated supply they use a curcuit with, of all things, voltage regulators. A kind of transistor type component that will supply a set voltage over a wide (but not too wide) variety of input voltages and current draws (mA's). Curcuits employing voltage regulators are usually delivering "clean" power since you can have a slight increase in current draw and the voltage regulator and its supporting componets will compensate and still deliver a steady output voltage. A transformer by itself on the other hand is rated at a particular voltage under a set load, in other words if whatever it is plugged into will draw a set amount of amps, it'll deliver its target voltage. But if that load increases, drawing more current, the transformer has no way to keep the voltage at its target.
 

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