vicwatson Registered User
#1

http://www.dealextreme.com/p/180w-hi-fi-stereo-amplifier-mp3-player-with-fm-radio-for-car-motorcycle-red-silver-sd-usb-90265

Or is it not that simple? It's say it's 12v but maybe using with a transformer ?

Thanks for help in advance

coylemj Registered User
#2

Yes those are standard speaker terminals around the back. Getting a 12V transformer (220V AC in, 12V DC out) will be easy, external hard disk drives use the same power.

One thing to watch out for: different regions have different frequency steps for FM radio so for example in the US they only use even decimals such as 90.2, 90.4, 90.6 etc. while in other regions they only use odd decimals such as 92.1, 92.3, 92.5 etc. In Ireland we use an increment of 0.1 MHz (100 KHz) so that we can tune to 98.1 or 104.4 MHz. You need to make sure that that device can tune in increments of 0.1 MHz if you want to use the radio in Ireland.

Fuzzy Clam Registered User
#3

coylemj said:


One thing to watch out for: different regions have different frequency steps for FM radio so for example in the US they only use even decimals such as 90.2, 90.4, 90.6 etc. while in other regions they only use odd decimals such as 92.1, 92.3, 92.5 etc. In Ireland we use an increment of 0.1 MHz (100 KHz) so that we can tune to 98.1 or 104.4 MHz. You need to make sure that that device can tune in increments of 0.1 MHz if you want to use the radio in Ireland.


De-emphasis on FM may be different too. 75 micro secs in the states as against 50 us here so if it's designed for the US market, it will sound a bit duller .

ZENER Registered User
#4

You'll also need a power supply that can provide 180 watts minimum ! At 12VDC that's going to be 15 amps. Not cheap !!

Ken

coylemj Registered User
#5

ZENER said:
You'll also need a power supply that can provide 180 watts minimum ! At 12VDC that's going to be 15 amps. Not cheap !!

Ken


At the risk of asking a stupid question - are speaker 'watts' the same as real watts? I mean how can each speaker burn 90 watts?

There is no way that you could feed that machine 15 amps, it would melt it straight away.

ZENER Registered User
#6

The amp is rated (and I use that term loosely ) at 90 W per channel RMS. These are real watts unless you want to get into phase shifting between the voltage and current! That's the energy the amp uses to move the speaker cone to produce the sound.

Also the 90 Watts per side is only the audio power assuming 100% efficiency. The real power the amp "uses" could be a lot more than this depending on the type of output stages employed in the amplifier. So you could be looking at in excess of twice that figure !

But I couldn't imagine that amp giving distortion free audio at those kind of levels so have assumed it may never be used to those extremes. The amp won't be delivering 180W continuously (unless you like listening to sine-waves ) so in real terms it would consume less power.

Ken

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