Power supply problem

[Max Roberts]

Many of you have seen my rig recently. If you don't know it goes Foxrox Octron > Tonefactor Cream Pie > BJF Blueberry > Tonefactor Huckleberry > Chunk Brown Dog > Chunk Agent 00Funk > Tonefactor 442 > Maxon PH-350 > Boss BF-2 > Roland Jet Phase.

I have two power supplies on my board because I need isolated outputs for my Jet Phase. So I have one power supply going into the Octron, the Brown Dog, the 00Funk, the 442, Ph-350, BF-2 and one of the inputs of the Jet Phase. The other is going into the other input of Jet Phase, the cream pie, blueberry and huckleberry.

Now, the first chain is ok, no problems with that. But when I put in all the daisy chain things into the other set of effects there is a horrible popping sound (like budum budum budum if you know what I mean )

I have tape over about 3 of the daisy chain bits of the problematic chain of effects if that changes anything?

Thanks in advance.

[Stuggi]

Daisy-chaining isn't really the way to go for hum-free sounds...
A power supply with separate transformer-taps for each effect would be the way to go, or a separate transformer for each output. Dunno if someone makes anything like this since I would probably make one myself if I needed one (if you're handy I could send you instructions, it isn't complicated at all...)

[Max Roberts]

It's nothing to do with hum, it's just an abnormal popping sound that shouldn't be happening.

[Stuggi]

Yeah, I phrased myself a bit badly (english isn't my first language ). What I meant was that when you're running multiple different circuits with a common ground that aren't specifically designed to work with each other, you're bound to get some problems. If the two powersupplies are otherwise somewhat identical (ergo, they're both capable of doing the same thing) I suggest that you try to swap 'em out and see if that helps.

[bongomania]

It's hard to know (from here) exactly which unit is causing the problem, but you can solve it on your end by removing pedals from the chain one at a time. I tend to agree that all of those pedals having a common ground is the issue, although it's probably just one or two of them making the noise. So after going through the process of elimination and figuring out which pedals are not happy having a common ground, I would get a Voodoo Labs PPII which has all isolated outputs, and use that for the finicky pedals, and your other non-isolated-output power supply for the pedals that work well on it.

[Max Roberts]

I tried unplugging the jet phase from the daisy chain and putting the daisy chain into the 3 pedals and they all worked with no noise, so it must be some kind of isolation problem.

But how come the same thing isn't happening to the other chain with the jet phase in the daisy chain?

[Stuggi]

Did you try switching around the powersupplies, or isn't that an option?

Now I'm not familiar with the Jet Phaser (I'm assuming you're referring to the roland ap-7), but since it's a vintage effect there might be an issue with the pedal itself. You could try using a separate wall-wart(s) to power the ap-7, and then daisychain all else, to see if there's an issue that individual isolated outputs would solve.

[bongomania]

Remember that ground is not only common with the pedals in each daisy chain, it is also common with the instrument cables that connect them. So even when you're isolating one or two of the power sources, the grounds are all still connected by patch cords.

[Max Roberts]

Originally Posted by Stuggi

Did you try switching around the powersupplies, or isn't that an option?

Now I'm not familiar with the Jet Phaser (I'm assuming you're referring to the roland ap-7), but since it's a vintage effect there might be an issue with the pedal itself. You could try using a separate wall-wart(s) to power the ap-7, and then daisychain all else, to see if there's an issue that individual isolated outputs would solve.

I haven't tried swapping them yet. It is the old AP-7 btw. I think it's just the isolation issue at the moment, easiest way for me to fix it is to get a Burkley Flatliner or Voodoo Labs Pedal Power so I have isolated power outputs to use on the Jet Phase.

[Stuggi]

T-Rex make a really cheap (100 € or so) power supply with 5 9V outputs, which are transformer-isolated from each other.

[Max Roberts]

Oh, I didn't know that it was isolated. I always tried to find out if it was but I could never find the information!

[Stuggi]

Originally Posted by bongomania

Remember that ground is not only common with the pedals in each daisy chain, it is also common with the instrument cables that connect them. So even when you're isolating one or two of the power sources, the grounds are all still connected by patch cords.

Oops, how was I able not think of that? It's insanely obvious... :/
Though you will not get any ground-loops that way, you need too separate paths to ground, which out get in the daisy-chains.

There could be another problem here as well. The pop-ing could indicate different ground potentials, which when added to the same pedal could introduce unwanted effects. Are your powersupplies earthed?

BTW, did I understand this right, the AP-7 needs two isolated power sources?

[Max Roberts]

Is this it?

Fuel Tank

[Stuggi]

Originally Posted by FunkyAssBassMan

Oh, I didn't know that it was isolated. I always tried to find out if it was but I could never find the information!

The ordinary fueltank isn't, but the junior has this feature.
http://www.t-rex-engineering.com/def...w=page&id=2783

[Max Roberts]

Originally Posted by Stuggi

The ordinary fueltank isn't, but the junior has this feature.
http://www.t-rex-engineering.com/def...w=page&id=2783

Oh yeah! Thanks.

[bongomania]

Originally Posted by Stuggi

BTW, did I understand this right, the AP-7 needs two isolated power sources?

It runs on two 9V batteries supplying +9 and -9, so the best way to do that using adapters is to have two isolated 9V supplies.

[Max Roberts]

Will the Fuel Tank junior (which was mentioned before) be able to have a daisy chain coming off one of the outputs? Or will there not be enough power?

Thanks for your responses so far!

[Stuggi]

From the T-Rex site:

Fuel Tank Junior comes with 10 standard pedal cables and a link cable that lets you power 5 separate units (total maximum of 120mA) off a single output

[Max Roberts]

Originally Posted by Stuggi

From the T-Rex site:

Oh, ok. That's cool. Does this mean each pedal can only have a 120ma draw or something? Sorry if I'm making no sense, I haven't got a clue about any of this power stuff.

[bongomania]

No, the part where it says "total maximum" means all pedals in the daisy chain added together. So it is only useful if you happen to have multiple pedals with very low current draw.