Gotta love what Alpine are doing with their headunits... :p - diyAudio
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Old 15th December 2003, 12:24 PM   #1
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Default Gotta love what Alpine are doing with their headunits... :p

It's inIngenious as it is rugged and reliable, our V-Drive MOSFET power unit boosts the voltage to 17.2 volts so the amplifier can convert this into a 60Watts x 4. With power to spare for large musical peaks, this amplifier will deliver the full dynamic range of digital sources with stunning sound clarity from bass, mid and high ranges


gotta love it... I mean, my maths suggests 37 watts rms with a PERFECT amplifier.. which isn't going to happen..

and what about the heat?? I doubt it would be class D... maybe its not class AB either.. maybe its class G or H or whatever it was.. lol but you are NOT going to get 60 watts X 4 from 17.2 volts, in a small almost sealed metal box, inside a car.. :P
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Old 15th December 2003, 01:12 PM   #2
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Default Re: Gotta love what Alpine are doing with their headunits... :p

Quote:
Originally posted by SkinnyBoy
It's inIngenious as it is rugged and reliable, our V-Drive MOSFET power unit boosts the voltage to 17.2 volts so the amplifier can convert this into a 60Watts x 4. With power to spare for large musical peaks, this amplifier will deliver the full dynamic range of digital sources with stunning sound clarity from bass, mid and high ranges


gotta love it... I mean, my maths suggests 37 watts rms with a PERFECT amplifier.. which isn't going to happen..

and what about the heat?? I doubt it would be class D... maybe its not class AB either.. maybe its class G or H or whatever it was.. lol but you are NOT going to get 60 watts X 4 from 17.2 volts, in a small almost sealed metal box, inside a car.. :P
No doubt there is marketeering. However with a Bridge Tied Load (BTL) 150 watts is available to a 4 ohm load assuming you can go from rail to rail. They probably can't but at a power supply voltage of 17.2V...more power is available than you might imagine.

Heat is a good point though the dissipation of a BTL configuration is quite high. Check out the National appnote for the LM-3886 bridged configurations.

Scott
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Old 15th December 2003, 01:19 PM   #3
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did I stuff up my maths?? hmm..... it is early morning...

no.. my maths is right.. 37 watts swinging the full 17.2 volt rail...

its a single 17.2 volts, not +- 17.2 volts...
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Old 15th December 2003, 01:23 PM   #4
Vigier is offline Vigier  Netherlands
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Skinnyboy,

just like all headunits that say 4x40W or 4x50W and have 4x18W RMS, the alpine also doesn't give you 60W RMS. The installation guide of the Alpine CDA7894RB says the output power is 60W MAX, NOT RMS.

The RMS power is around 25W RMS.

Grtz, Joris
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Old 15th December 2003, 01:29 PM   #5
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Quote:
Originally posted by Vigier
Skinnyboy,

just like all headunits that say 4x40W or 4x50W and have 4x18W RMS, the alpine also doesn't give you 60W RMS. The installation guide of the Alpine CDA7894RB says the output power is 60W MAX, NOT RMS.

The RMS power is around 25W RMS.

Grtz, Joris

but the guy at tonkins said the headunit would give more power than an old Clarion amp my friend bought and I fixed that it using +-20 volt rails...

and they had "50 watt" headunits, and then they released new models that were 60 watts... and they DO NOT say max... or rms... or anything...
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Old 15th December 2003, 08:54 PM   #6
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Quote:
Originally posted by SkinnyBoy
did I stuff up my maths?? hmm..... it is early morning...

no.. my maths is right.. 37 watts swinging the full 17.2 volt rail...

its a single 17.2 volts, not +- 17.2 volts...

Yup. You're right. I'm smoking illegal substances apparently. That's what I get for posting on 3 hours sleep.

Scott
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Old 16th December 2003, 12:27 PM   #7
bknauss is offline bknauss  United States
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Alpine might claim 25W RMS, but at what THD%?

Just save up and get an amp to drive your speakers.
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Old 16th December 2003, 08:58 PM   #8
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so.. if an amp has a single 17.2 volt rail, is 37 watts the maximum power it can give, but with a huge amount of clipping?? or, would it be less than that cos the amp cannot swing the full rail even when it is clipping beyond belief??
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Old 16th December 2003, 10:28 PM   #9
Vigier is offline Vigier  Netherlands
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Hi,

As far as I know, the 25W RMS is at 1% THD+N. (not measured by Alpine, but a German carhifi magazine)

If you don't want to turn the volume high, the power of those amplifiers is enough, but if you want a little more, you MUST have an external amplifier.

Right now I have a Pioneer DEH-P77MP (the CDA7894RB has been stolen a few months ago), and use a Emphaser EA4100-500 to get enough power. I NEVER use the amplifiers in the headunit because of the lack of power, en the poor quality (compared to good external amplifiers)

Grtz, Joris
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Old 16th December 2003, 10:33 PM   #10
paulb is offline paulb  Canada
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Quote:
Originally posted by ScottRHinson



Yup. You're right. I'm smoking illegal substances apparently. That's what I get for posting on 3 hours sleep.

Scott
Come to Canada. It's practically legal.
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