Hi, I know that you guys have great knowledge about things electrical/electronic, so I'm asking for some info. I need to get an external power adapter for an out-of-production synthesizer module I have. The specs in the manual call for the following: "9 VAC, 5 Volt Amps external Transformer". The 9vac I understand, but what is "5 volt Amp"? I just need to know the amperage rating , right? Can you figure it out from these specs... Any help would be greatly appreciated... Thank you, Angelo
Try Goodwill. 5va = approximately 5 Watts. P or, I=P/E P=Power in Watts I=Current in Amps E=Voltage in Volts I=5/9 or .56A (560 mA) The higher the Amp rating, the cooler it will run. The load will only draw what it needs, so anything over 600 mA should be OK. McSparky On 10/27/06, Angelo wrote: <Snip>
What kind of synth module is it? I'm a keyboard player, and have always had good luck with the guys at Sweetwater Sound (www.sweetwater.com) to take care of me, even with obsolete parts like this. Tim On 10/27/06, Michael Mccandless wrote: <Snip> -- Timothy Wat timothywat
Angelo. volt amp, roughly is volts times amperes.... since you already know the volts 9... you have to figure out 9 times what will equal roughly 5.... say about 600 milliamperes. (ok not exact but you always want a little head room) if it takes 5 va you want a power supply that supplies a bit more than this so you are not running it at 100 % it's capacity all the time. They run cooler and last longer. Radio shack sells a universal adapter that is good for an amp or so that should be oh maybe 20 bucks most?? You can select the voltage on it, and select the tip to use, there are a few models and they have a whole rack with different tips to choose from so it plugs into your item properly. If need be, bring your thing in with you and you can compare to make sure you have the right tip for it. Aaron
Tim, I actually have two units that use the same adapter. They're the Alesis Nanosynth and Nanobass. I'll be using the Nanosynth with an EWI 4000s windcontroller. I'm not really looking for original equipment, but rather a Radio Shack multi voltage/tip unit. I just needed to know the minimum miliamps needed...and thanks to you guys, I do :-) Ciao, Angelo Btw, I've dealt with Sweetwater before and they are good... <Snip>
Angelo, Be sure to check polarity. Mike (just plain)
Make sure it is AC. McSparky On 10/28/06, Michael Dhabolt wrote: <Snip>
Thrift stores usually have a rat's nest of these "Power adapters" or "Wall warts" hanging somewhere, or they're in a box or drawer somewhere near the electronic doo-dads. If you need to save $$, a 12-13vdc adapter would work. Cheers -RayO, aka Opa! Got Grinder?
A DC adapter may or may not work. Depends on hot the AC is rectified. The spec calls out an AC adapter. McSparky On 10/28/06, raymanowen wrote: <Snip>
The OP says the manual wants "9 VAC, 5 Volt Amps external Transformer" A lot of wall bricks are DC as indicated in ray's post. Just in case you thought it was gonna be easy. ;-) Dean raymanowen wrote: <Snip>
I made my previous comment because your music box already has an internal rectifier and filter capacitors. If the synthesizer waveform generators are voltage critical, the internal power supply (5VA !?!?) already has a voltage regulator chip in it. 9vac rms will give 12vdc (+) when it's rectified and filtered, so if you can't find a 9vac 1/2amp (+) adapter, many others will work, including DC! (The waveform generators sure don't work on AC even in China.) Cheers -RayO, aka Opa! On 10/28/06, raymanowen wrote: <Snip> "When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty Wichita (ex- NYC Paramount) WurliTzer- 1976
No, the DC produced from 9VAC will depend on the type of rectification used - half wave, full wave, doubler ... all produce a differnt DC voltage. Best to just stay with the specs, and find a 9VAC source On 10/28/06, raymanowen wrote: <Snip> -- "In theory, there is no difference between theory and practice; In practice, there is." - Chuck Reid
I was under the (mistaken?) impression that polarity wasn't an issue with AC... <Snip>
I've learned to avoid assuming that a circuit may be designed a certain way. There's no end to the possibilities. Inputs to power supply circuits aren't always as straight foreward as one might assume. Some may contain series caps, etc. Without a schematic, or visual perusal, it's not a good idea to connect non conforming to equipment. It will most likely work 99% of the time, but Murphy has a way of finding that 1% when least expected. McSparky On 10/28/06, raymanowen wrote: <Snip>
Angelo, in conventional thinking polarity generally isn't... or wasn't an issue with A/C however, given that many devices have floating grounds, swaping polarity can potentially give one a nasty shock if they were to touch two a/c devices where one was wired up with the wires swapped. Swapping the hot lead and the neutral lead can cause problems in some devices. With a wall transformer like your device needs, were only talking 9 volts, and that 9 is it's own totally isolated system, so it's a non issue there, but for stuff that just 'plugs into the wall' yes, polarity is an isuue. Aaron who is saying "neutral is NOT ground"