Build Your Own Arcade Controls Forum
Main => Main Forum => Topic started by: Jeehemdee on November 15, 2002, 12:24:15 pm
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This is surely a stupid question ???
But I've to change the adapter of the amplified speakers of my cabinet (12v, 1000ma)...
But they do have 2 kinds of adapters at Radioshack:
1) AC to AC
2) AC to DC
I think it's the second one, isn't it ?
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F004%5F001%5F001%5F000&product%5Fid=273%2D1779 (http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F004%5F001%5F001%5F000&product%5Fid=273%2D1779)
Thanks !
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This is surely a stupid question ???
But I've to change the adapter of the amplified speakers of my cabinet (12v, 1000ma)...
But they do have 2 kinds of adapters at Radioshack:
1) AC to AC
2) AC to DC
I think it's the second one, isn't it ?
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F004%5F001%5F001%5F000&product%5Fid=273%2D1779 (http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F004%5F001%5F001%5F000&product%5Fid=273%2D1779)
Thanks !
You really have to look for a label on the speakers to see what it says. Most of the time it's AC-DC, but I actually own some speakers that use the AC-AC type adapter.
The rule of thumb here is: There is no rule.
RandyT
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The rule of thumb here is: There is no rule.
I though the rule was:
1. Try it and find out
2. If it fails, see number 1.
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The rule of thumb here is: There is no rule.
I though the rule was:
1. Try it and find out
2. If it fails, see number 1.
That rule only applies if you have a spare set of speakers :)
Seriously though, it probably wouldn't hurt anything, but you never know!
Randy
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Well, let me put it this way.
The only difference between an AC-DC power supply and AC-AC power supply is that the AC-AC is only a transformer, while the AC-DC power supply contains a transformer with a full-bridge rectifier circuit built into it.
AC-DC case (using 12VDC supply)
If the input to your amplifier is in fact 12VAC, this will most likely be full rectified to about 10 VDC after full-wave rectification (Vout = 2*12*SQRT(2)/pi) and probably won't hurt the amplifier as this goes into a 78XX type linear regulator which can withstand a higher voltage. In fact after the diode voltage drops, the 12VDC input will be around the 10VDC which is what a 12VAC full-rectified would be equivalent to.
AC-AC case (using a 12VAC supply)
In this case, you have a problem. Your amplifier requires 12VDC and you are inputting 12VAC which gives peak voltages of almost 18V which could likely damage your amplifier. Vpeak = Vrms * SQRT(2)
So better, make sure before you plug in a supply.
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Wow !!
Liche,
Thanks very much for a so complete answer !!
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Jeehemdee,
If you use and AC/DC converter it will put you on a hiway to hell! ;D Just don't do it!
Rocky
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Jeehemdee,
have you tried emailing the company who made the speakers? Often they will tell you whether it is ac or dc (and if dc, what polarity) that the speakers need.
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Actually, if you can open up your speakers (amplifier) and trace your input, you can very EASILY determine whether its AC or DC.
If the input wires / circuit board traces go directly to your other components on the amplifier, or into a 3 terminal device which the identifier LM78xx such as LM7805, LM7809, etc..., then the input is DC.
If the input wires / circuit board traces go to either:
(4) cylindrical devices (usually black with a single stripe on it) - these are diodes for the full bridge rectifier
OR
a single round device which usually has the following designations on it (+, -, AC, AC) or (+, -, "sine wave", "sine wave") where "sine wave" is a small graphical representation of a sine wave
then your device requires 12 VAC.
This is very simple to see, and if you have a digital camera, you could even take a picture and post the link here. I could easily tell you just by looking at the picture if its AC or DC input.
Then again, just contact the manufacturer as the last person stated.