A fair question (I think)

[Anonymous]

Dear fellow Sunn Sickos, I have a non-Sunn question that demands answering; you folks here I trust to guide me.

The problem:  I like Alesis effects as part of my PA system.  Alesis gear uses the outboard power transformers, or wall-warts, if you will.  I am crazy nuts downright fed-up with the wall-warts.  They waste space, they break, they get lost, they make a mess, and in general they suck.

My proposed solution:  I want to power up to six Alesis devices, all 9VAC.  The biggest Alesis wall-wart I have is 120VAC 60Hz 15W input, and 9VAC @ 830 mA output.  Is there any reason I can't (or shouldn't) use a 50VA 9VAC tranny with parallel outputs for the Alesis stuff, with the 120VAC primary plugged into a cheap Furman power conditioner?  The Furmans advertise 1.8 kW capacity.  Is this even neccessary?  I can't imagine there being a whole heck of a lot of regulation in the wall-wart.  So six at 15W is 90W.  Proper and safe wiring is assumed.

This seems too simple.  Am I missing something really obvious?  If so, please let me know gently.  I really do appreciate the brains and common sense that tend to gather on this site.  Thanks.

[Fred Cook]

The issue may be more regulation, i.e., 9v regulated or not. (This assumes that you have the polarity of your adapters right, etc.)

I would e-mail Bob Weil of Visual Sound. They sell a "One-Spot" wall wart which is regulated and, with their daisy chain adapter, can run up to four devices. (Add another adapter, etc.) He can probably answer your questions immediately. Unless one of your Alesis effects is a real power hog, I suspect that one or two of these beasts, with the daisy chain adapter will get you in business.

Look Here --  http://www.visualsound.net/1SPOTpage.html

Failing that, Radio Shack  almost certainly  has something you can use. Hint: If you build your own cable chain, use zip cord, not for the amperes, but rather to protect against people stepping on the  wire, etc.

Hope this helps.

[Don T.]

Hello:
 Generally the AC supplies are unregulated. They are supposed to have 9v output at the rated current draw, however, the volts output unloaded is considerably higher. Polarity makes no difference in the AC supply as both leads have sign waves present. What the device is looking for is a regulated + - DC supply (required by most ICs)which is probably done inside. You could check this on the schematic if you have one. As long as the AC you are applying to the device does not exceed the voltage breakdown of the components (caps & transistors) in the regulator then you will be OK. be sure to verify this before trying it or "POOF" the smoke will come out.
Don T.

[Rocketboy]

Thanks Don.  That's a good point regarding the unloaded voltage.  Maybe a 1-megohm, 1-watt resistor at any unused output should even the overall output voltage.  The Alesis devices do have a range of acceptable operating voltage, but I sure haven't been able to get that info from Alesis.  Since my installation will be "semi-permanent" in the sense that the devices will be infrequently changed, the dummy load at each unused output sounds like a reasonable prelude to any smoke test.  So does a DVM!  Thanks!
Ric