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-   -   Alpine ipod head unit (http://www.diyaudio.com/forums/car-audio/106087-alpine-ipod-head-unit.html)

vizion 30th July 2007 06:46 PM

Alpine ipod head unit
 
hello guys,


what is the voltage of pre-outs for Alpine's ipod head unit ? 350mv or 4 volts ? A typical cd player at home would be 1 volt for comparison.


Thanks.

junglejuice 30th July 2007 10:55 PM

You would have to assume that it would be 4v like the others...

vizion 30th July 2007 10:58 PM

I checked with Tru Technology and Zed Audio. Head units only put out 350 mv loaded. Home cd units put out around a volt. 2 volts and higher are just for measurement. But with music, it's only 350 mv.

junglejuice 31st July 2007 12:49 AM

I somehow don't think so, music is very dynamic so 4v head units will put out up to 4v when the output is at it's maximum and I fail to see how a 10000 ohm load can drag that down to 350mv....

Perry Babin 31st July 2007 12:59 AM

What load did they use to test the RCA outputs?

No normal amplifier front end has a low enough input impedance to significantly pull down the output of a head unit. Most head units produce at least one volt RMS.

I measured the output voltage of a Pioneer DEH-P3500 I have on the bench (rated at 2v). The following voltages are RMS. The head unit is capable of slightly greater output but the digital volume doesn't allow fine adjustment of the level at full volume. This was done with a 1hHz signal.

Unloaded: 2.07v
Loaded with 10K resistor: 1.90v
Loaded with a 1k resistor: 1.09v
Loaded with a 600 ohm resistor: 0.83.

junglejuice 31st July 2007 01:50 AM

Really early head units put out 500mv then they went up to 1v then 2v and then a few at 4v or even higher.
Of course that assumes the programme material is recorded at the maximum level that a cd can handle.
I have an Autosound 2000 test disc that has test tones on it that is recorded at the limit of a cd and used it to measure the output of my 14 year old Alpine 7620 and whilst I can't remember the exact output voltage it was well in excess of 350mv using a cro and a fluke mulitmeter and yes it was loaded with a 14 year old Alpine 3331 equaliser.
Now maybe the sources you contacted are referring to an averaged level of an average music cd but certainly not a cd recorded near to the max.
Just a thought what sort of input level do the Tru and the Zed amps accept?

vizion 31st July 2007 03:47 AM

thanks for the input, guys.


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