On 17/01/2011 01:30 PM, scott wrote:
>> I wouldn't have thought there's any relationship at all between quality
>> and power consumption. Not for a DAC, anyway.
>
> In general more power means you have more possibilities to do stuff to
> increase the quality. If you've designed what you think is a great DAC,
> and someone tells you to reduce the power by 25%, chances are the
> quality will suffer as a result. All sorts of things used to increase
> quality (eg digital filters, analogue filters, voltage regulators) draw
> power, and usually can be removed/replaced to reduce the power.

I still rather suspect that rather than put in a high-quality DAC and a 
low-quality DAC, they'll just not bother with the high-quality one at all.

>> Either way it's a pretty low-power device.
>
> Only if it's designed that way, according to Wikipedia a typical DAC for
> PC soundcards is the CS4382, which draws almost half a Watt during
> normal operation - not really suitable for a portable device!

OK. But also not *designed* for a portable device either. I'm sure 
somebody has come up with much more frugal designs.

>> Presumably the transmitter and backlight use vastly more power...
>
> Backlights usually use around 100 - 200 mW depending on the screen size,
> but I don't think they usually stay on (at least not at full power)
> whilst music is playing, do they?

I would hope not.

> The transmitter should be on almost zero power whilst playing music

I don't know that much about GSM, but doesn't it have to periodically 
broadcast to keep in touch with the network?

> and judging by the talk times and
> battery capacities, looks around half a Watt whilst in a call.

Mmm, maybe.

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