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I feel dumb asking this ...

E

elevator_opratr

Guest
... this is probably something covered in electronics 101. LOL

Anyhow, I have a Radio Shack SSM-60 Stereo Sound Mixer and I had lost the AC Adaptor. I finally found a pile of AC adaptors in my closet and am trying to figure out which one belongs to this mixer.

The back of the mixer says AC 18V. The adapter I think belongs to it says "Input 120V 60Hz 18W" and "Output DC 13.5V 1A"

Is this the right adapter? Is 18V and 18W the same?

Again, sorry for the dumb question. Insult me all you want. :)
 
> The back of the mixer says AC 18V. The adapter I think
> belongs to it says "Input 120V 60Hz 18W" and "Output DC
> 13.5V 1A"
>
> Is this the right adapter? Is 18V and 18W the same?

No, what you need to look at is the output from the adapter, which is 13.5V DC. You would need an adapter that outputs 18V AC.
 
> No, what you need to look at is the output from the adapter,
> which is 13.5V DC. You would need an adapter that outputs
> 18V AC.

An adapter that outputs 18V AC is going to be a difficult find.

DEFINITELY don't plug any DC adapter into the unit. At best, it simply won't work. At worst, you'll fry hardware.

Later,
Matt Smith
 
> ... this is probably something covered in electronics 101.
> LOL
>
> Anyhow, I have a Radio Shack SSM-60 Stereo Sound Mixer and I
> had lost the AC Adaptor. I finally found a pile of AC
> adaptors in my closet and am trying to figure out which one
> belongs to this mixer.
>
> The back of the mixer says AC 18V. The adapter I think
> belongs to it says "Input 120V 60Hz 18W" and "Output DC
> 13.5V 1A"
>
> Is this the right adapter? Is 18V and 18W the same?
>
> Again, sorry for the dumb question. Insult me all you want.
> :)
>

search (ebay) for "18v ac"... most of those will work. as long as
its above 330ma. probably get it for around $15 shipped!
 
Clarified response...reread?

> The back of the mixer says AC 18V.

Before taking anything marked on a Radio Shack product as gospel find
the manual. If both the manual and the label say AC 18V then it's
probably correct. If not, I do wish you well.

> The adapter I think
> belongs to it says "Input 120V 60Hz 18W" and "Output DC
> 13.5V 1A"

The "Input" information just means the adapter wants to see standard
plug-in-the-wall power as you have in your home (120 Volts/ 60 Hertz).
When plugged in it'll consume 18 Watts. Divide 18W by 120V and you
get the current drawn by the wall-wart; 0.15 Amperes (150 milliAmperes).

On the output side, it means the adapter contains not only a
transformer (to turn the 120VAC into 13.5VAC) but also some diodes
and (we might hope) some filtering (capacitors/inductors) and,
with lots and lots of luck, some sort of regulation, probably
a packaged device.

> Is this the right adapter? Is 18V and 18W the same?

Probably not the right adapter unless the mixer is mis-labeled.

18V and 18W are not the same.

V means "Volts", effectively a measure of electrical "pressure".
W means "Watts", an instantaneous measurement of power consumption.
They're indirectly related, Wattage being determined through
multiplying Voltage by Amperage.

If your mixer is labeled only "AC 18V", there isn't enough
information to calculate how much power (how many Watts) it needs.

The wall-wart you're looking at is capable of a maximum of 13.5
Watts (13.5V x 1A = 13.5 Watts). So...not only is the output
of the wrong kind...DC instead of AC, the Voltage is too
low but the available current (1 Ampere) is pretty high! Typically
wall-warts, unless they're very large, provide about 1/2 of
that (around 500 milliAmperes).

I've seen devices that specify a nominal voltage but will run
happily on quite a bit less if you don't push them. If they
work at all, the maximum audio volume you can get out of them
without extreme distortion is severely limited. But in this
case it's the DC vs. AC that's the killer.

Other problems very commonly overlooked:

1. Physical size of the connector on the mixer vs. the physical
size of the connector on the cord off the wall-wart.

2. When the device (in this case the mixer) wants to see DC
you have to investigate the polarization of the connectors. Some
makers make the outer shell of the male connector negative with
the "hole" in the connector positive. BUT, a few do it the
other way around. Look for markings like these:

- -Co- + (with the o tucked inside the C) indicating the
shell is negative and the "hole" positive".

or

+ -Co- - Shell positive, hole negative.

The - closest to the C and the o are just to point to the
polarity symbol adjacent to them.

I know...way too wordy...but I figure a question deserves an answer that
not only satisfies the question but offers some information that will help
in future situations. There is only ONE dumb question; the one that a
person doesn't ask for fear of having intelligence question. How in hell
do we add to intelligence without asking questions???<P ID="signature">______________
I once took something seriously.
And was accused of shoplifting.</P><P ID="edit"><FONT class="small">Edited by Les on 09/10/05 11:28 PM.</FONT></P>
 
>
> If your mixer is labeled correctly it requires one full
> Ampere at 18 Volts (18W/18V=1A). The wall-wart you're
> looking at is capable of a maximum of 13.5 Watts
> (13.5V x 1A = 13.5 Watts). So...not only is the output
> of the wrong kind...DC instead of AC, the Voltage is too
> low and there is insufficient power available out of the
> package.

FYI, The adapter that comes with it is only 330ma... I think the
18w he was getting was on the other power adaper he got.



> I know...way too wordy...but I figure a question deserves an
> answer that
> not only satisfies the question but offers some information
> that will help
> in future situations. There is only ONE dumb question; the
> one that a
> person doesn't ask for fear of having intelligence question.
> How in hell
> do we add to intelligence without asking questions???
>

agreed!!
 
> >
> > If your mixer is labeled correctly it requires one full
> > Ampere at 18 Volts (18W/18V=1A). The wall-wart you're
> > looking at is capable of a maximum of 13.5 Watts
> > (13.5V x 1A = 13.5 Watts). So...not only is the output
> > of the wrong kind...DC instead of AC, the Voltage is too
> > low and there is insufficient power available out of the
> > package.
>
> FYI, The adapter that comes with it is only 330ma... I
> think the
> 18w he was getting was on the other power adaper he got.

I went back and revised things, having falsely assumed that
the 18 Volts required by the label was at a full amp. My
bad. I missed where the 330 mA came from...is it that you
have a similar unit? If so, any manufacturer name and/or
part number? More complete specification so he could shop
around more easily?

Thanks for catching this!<P ID="signature">______________
I once took something seriously.
And was accused of shoplifting.</P>
 
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