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Topic: ? re: AC wall warts |
Jerry Overstreet
From:
Louisville Ky
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Posted 11 Oct 2008 8:43 am |
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For you electronics whizzes here....can a single A/C wall wart power supply be used to power up more than one device? I know there are several possibilities for DC daisy chaining, but what about AC? Must AC devices of identical power requirements [ac voltage output and milliamps] have an individual transformer per piece?
I have several of the Boss Pro rm pieces that require the same 12v AC power supply. Just wondering if I can use a multi-jack cable to power up a couple of them.
Thought I'd ask here first before I just "up and try it". Thanks in advance for your input. JO. |
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Johnne Lee Ables
From:
Minnesota, USA
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Posted 11 Oct 2008 8:59 am Re: ? re: AC wall warts
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| Jerry Overstreet wrote: |
For you electronics whizzes here....can a single A/C wall wart power supply be used to power up more than one device? I know there are several possibilities for DC daisy chaining, but what about AC? Must AC devices of identical power requirements [ac voltage output and milliamps] have an individual transformer per piece?
I have several of the Boss Pro rm pieces that require the same 12v AC power supply. Just wondering if I can use a multi-jack cable to power up a couple of them.
Thought I'd ask here first before I just "up and try it". Thanks in advance for your input. JO. |
It depends on the limitations of the power supply and the total draw of each attached device. In my Ham Shack I always err on the side of caution, but then I'm running 1500 watts and a huge current draw.
JL
_________________
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"In the course of a long life a wise man will be prepared to abandon his baggage several times." |
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Ray Minich
From:
Bradford, Pa. Frozen Tundra
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Posted 12 Oct 2008 4:06 pm
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| This should be possible because I have two "stomp box" power supplies for Boss gear that have a few (like 6 or more) of the plugs wired in daisy-chain to the wallwart. They even make an adapter cable that has one female (to plug in to the single wall wart male connector) and 6 or more male connectors (for the devices) just for that purpose. |
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Bob Bowden
From:
Vancouver, BC, Canada * R.I.P.
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Posted 12 Oct 2008 4:28 pm
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I use the Godlyke PA-9 Power-All
The Visual Sound 1 SPOT looks very similar with near identical specs.
Simple, easy to use and gets the job done. |
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Jon Light
From:
Saugerties, NY
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Posted 12 Oct 2008 4:58 pm
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| Johnne's answer is the correct one. First of all, the other responses are about dc power. But that's beside the point---the rules will apply to ac or dc. It doesn't matter that the cables will allow multiple connections. What matters is the current draw of the devices and the current specs of the power unit. Different devices draw different current. Some require very little power---you can run a bunch of them on a daisy chain. Some draw a lot---then you have to pay attention to the cumulative mA numbers. |
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Jack Stoner
From:
Kansas City, MO
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Posted 13 Oct 2008 2:20 am
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In order to use one power supply, all the devices must first use the same voltage. Some devices require an AC voltage, some devices require an unregulated DC voltage and some require a regulated DC voltage. And for the devices that use DC voltage you have to contend with the polarity. Thus "one size does not fit all".
9VDC unregulated seems to be a common power requirement of many stomp boxes, but not all. Generally, if you stay with one brand they will have the same voltage requirement (but will vary in the power (current) requirements). |
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Jerry Overstreet
From:
Louisville Ky
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Posted 13 Oct 2008 6:55 am talkin' 'bout AC output here
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...yeah, I'm hip to the dc multi-use supplies like the Godlyke. I have one of those [1.7 milliamp] plus a few others. I'm aware of the polarity issue with those. I don't pay much attention to the power requirements of my boxes that use those. If some of them were really widely varying voltage, might be different. Most of them are 9v. but they can range between 6 and 12 volts dc. I just make sure I maintain proper polarity and gang those fx units together.
I sometimes use one of those cheapo universal dc adaptors set at the highest level [12v] to power up an old Ibanez echo stomp box requiring 18 volts....No problem so far.
My question is about devices that require wall warts with AC output. To be specific, 2 pieces of Boss Pro 1/2 sp. gear. Each has a seperate 12v, 500Ma ac transformer, power supply. Trying to reduce the clutter in a rack case. I was just wondering if I could use only one of those to power both devices. Perhaps someone here has had some practical experience doing this.
I don't recall ever seeing a power supply for powering multiple pro audio devices that use ac output. I don't know if it's because they could be confused for dc units and erroneously applied or what but there must be a good reason. |
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Jon Light
From:
Saugerties, NY
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Posted 13 Oct 2008 12:37 pm
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Actually, Voodoo Labs Pedal Power is available in a multi- output AC version HERE
The question is, what is the current draw of both of your 12 volt ac Boss devices? I'd look in the manual for those specs. The 500mA power supply may be provided because the one unit needs all of that that or it could be because that was the power unit they happened to have and it has more than enough to handle two units. Since they are both 12v and since polarity is irrelevant, current draw is all that's left to consider. |
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Jerry Overstreet
From:
Louisville Ky
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Posted 13 Oct 2008 4:39 pm
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Thanks Jon. My old internet terminal freezes up when I try to download pdf files, so I couldn't get to the manual to review the current output of this voodoo labs unit. A transformer of this design might be a possiblity at a more affordable price.
My units call for 500 ma ea. piece. So, I guess a ps of at least 1000ma would be indicated to run 2 units. I'm familiar matching dc devices to a sufficient amount of ma output, but I wasn't sure that ac devices would behave the same way. |
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Jon Light
From:
Saugerties, NY
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Posted 13 Oct 2008 5:10 pm
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here's the pertinent info:
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Jerry Overstreet
From:
Louisville Ky
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Posted 13 Oct 2008 5:53 pm
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| OK Thanks. Thanks to Johnne Lee and the other guys that took time to respond....now, back to the LCS. |
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Jim Sliff
From:
Lawndale California, USA
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Posted 14 Oct 2008 4:58 am
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With two 500ma units I'd use at minimum a 1200ma supply; always leave yourself a litle cushion, as wall warts are seldom exactly on spec. Voltages and current vary quite a bit.
| Quote: |
| And for the devices that use DC voltage you have to contend with the polarity. |
You have to contend with polarity in AC circuits as well - it's not as obviously critical (things will work reversed) but it does affect grounding, and you can spend a lot of time chasing hum if you mix polarities.
_________________
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Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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