grelcar
New member
Is the internal DAC used when streaming from a digital source and not using analog line input?
DAC question
- Thread starter grelcar
- Start date
It doesn't matter which input is used. When using the analog line input, then the WiiM Amp's in-built ADC will be used, but this has nothing to do with the DAC.
DAC stands for Digital to Analog Converter. Whenever you use an analog output (the speaker binding posts are the only analog output), the DAC will be used. Right now the only digital output (not using the DAC) is Bluetooth. Bluetooth uses lossy compression and is not intended for highest quality output, anyway.
A future firmware update will enable USB output, so the USB A socket can be used to sends a digital signal to an external DAC.
DAC stands for Digital to Analog Converter. Whenever you use an analog output (the speaker binding posts are the only analog output), the DAC will be used. Right now the only digital output (not using the DAC) is Bluetooth. Bluetooth uses lossy compression and is not intended for highest quality output, anyway.
A future firmware update will enable USB output, so the USB A socket can be used to sends a digital signal to an external DAC.
grelcar
New member
I was of the understanding that a class d amplifier used a digital input signal. When streaming from a digital source would there be a need to convert the digital input to audio and then back to digital for the amplifier input or does some sort of digital to digital conversion take place to convert the source digital signal to a format that can be used by the amplifier?
Brantome
Moderator
Are you meaning things like the conversion of a FLAC music file which is converted to a digital stereo PCM for output or further processing by the amp?
It is a common misconception that the d in class d stands for digital.
grelcar
New member
I have a basic understanding of class d amplifiers, also referred to as switching amplifiers. Is the PWM input used by a class d amplifiers a digital signal. Is this signal created by the DAC or some other component. I have seen some class d equipment described as having all digital operation.
Last edited:
Mr Ee
Major Contributor
The "input" can be either analog or digital, more usually the former. The input is not PWM, that's what's output and used to turn the transistors on and off.
A dac, by definition, converts a digital signal to analog.
Maybe take a quick look at the Wiki page on class d amps. The first few paragraphs may help clear some things up for you.
Digitally controlled switching amplifiers do (still) exist (like in the case of Lyngdorf). But most designers lean more towards analogue-controlled switching amplifiers.
Shortcut for a clear definition (quite old by now, Putzeys himself later did some work to overcome the restrictions with digital input Class D, but still valid):
The Truth About Digital (Class D) Amplifiers
Firstly I'd like to point out that "digital amps" is a misnomer. There are two categories: Analog-controlled class D. Switching amplifiers…
www.audioholics.com
The TI TPA3255 is of the latter type, so you can only feed it analogue input signals.
grelcar
New member
harkpabst, thanks for the link. This explains why the conversion from digital is necessary, because the amplifier module requires an analog input. The conversion to PWM also takes place within the amplifier module.
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