[Voyage-linux] Re: Any Hardware Voltage Monitoring/Usage Sensors Available for ALIX boards?

[Jon Meek]

I believe that PC Engines recommends 18 volt power for ALIX boards
(other than the alix1d which requires 12 v). In any case, PC Engines
sells only 12v and 18v power supplies if you buy from them
directly. The 18 v PS from PC Engines is rated at 1.2 A DC but from
the measurements below much less power is needed, and the switching
power supply will waste little.

Here are some measurements for DC and AC (120 volt) power consumption
by an alix2d3 with various power sources:

Switching "Wall Wart" Power Supply

 14.85 v  0.210 A   3.1 W DC

Add HRT MusicStreamer II USB DAC:

 14.82 v  0.29 A  4.3 W    45 mA   5.4 W AC
 18.11 v  0.24 A  4.3 W    48 mA   5.8 W AC


Linear Lab Supply

 10.97 v  0.39 A  4.3 W   0.29 A  34.8 W AC
 12.03 v  0.36 A  4.3 W   0.29 A  34.8 W AC
 13.00 v  0.33 A  4.3 W   0.29 A  34.8 W AC
 14.00 v  0.31 A  4.3 W   0.31 A  37.2 W AC
 15.00 v  0.29 A  4.3 W   0.33 A  37.2 W AC

Linear Lab Supply with No Load: 0.15 A  18 W

So, the switching power supplies are much more efficient as
expected. There may be a question of noise from a switching power
supply, but I assume that the optical isolation in the Ayre DAC will
handle it. Of course you have a computer here with its own switching
noise.

I probably have more switching wall wart voltage choices, but the
results will probably not vary much.

Be careful with limiting the current to your alix board, it is going
to have the need for higher power at times, just like your audio
amplifier!

Jon



On Mon, Jan 23, 2012 at 7:33 PM, linux123 <24bits at comcast.net> wrote:
>
> I wanted to thank everyone who responded with this information. It’s a shame
> that there are no software based sensors but I guess at the end of the day
> it would only add additional overhead.
>
> It’s interesting to hear that there would be a 5v regulator of some sort
> just after the DC Input jack. If that's the case then I can see no reason
> why the manual for the board tells you to use between 7-20v MAX. I chose the
> 15.5v value only because it matched the Wall Wart that came with the board
> and planned on working backwards from there in terms of Input power once I
> felt I had sufficient information to pull the trigger....err, I mean, twist
> the knob lower
>
> One thing I will mention is that I did have the board dialed down to the
> 12.5v range for a few hours one evening during a jam session and swore the
> soundstage seemed a bit more distant than usual but it may have been the
> beer talking to me. I will need to do further testing before I am willing to
> say much more about that occurrence.
>
> To "Jeff Mai",
>
> I would love to be able to feed the board between 9-10v but before I try it
> out I am going to place a call into Ayre to find out how much juice the DAC
> is looking for to run its circuitry. If the DAC is looking for 5v, then I
> may need to stay around the 13.5-14v range for Input power in order to keep
> everything happy.
>
> Thanks again
>
>
>
>
> --
> View this message in context: http://voyage-linux.34677.n3.nabble.com/Any-Hardware-Voltage-Monitoring-Usage-Sensors-Available-for-ALIX-boards-tp3680043p3683456.html
> Sent from the Voyage Linux mailing list archive at Nabble.com.
>
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