S.M.S.L PO100, PO100 PRO & PO100 AK - Measurements (Digital Interfaces & DAC)

[Witterings]

You can control volume in the digital domain (i.e. via the phone), but doing it this way reduces dynamic range.

Is that the same with a PC do you know and in which case I guess I should set the PC to 100% volume ?

 

[Pearljam5000]

You can control volume in the digital domain (i.e. via the phone), but doing it this way reduces dynamic range.

So how can you control the volume without reducing the dynamic range?

 

[Ted B]

Is that the same with a PC do you know and in which case I guess I should set the PC to 100% volume ?

It is typically not a problem to make nominal reductions in volume this way when using a PC to feed a DAC, but large reductions may have an audible impact. If you have a means of controlling the volume further downstream, I would set the PC's digital output volume at around 95%, just to create a small buffer such as not to overdrive the DAC, and control volume either at the DAC or in the analog domain.

So how can you control the volume without reducing the dynamic range?

The easiest answer is control it in the analog domain, for example, with a preamp placed between DAC and amplifier or the gain (volume) controls of an amplifier. Modern DACs with an onboard (digital) volume control may use upsampling to mitigate the effect. If the DAC is in powered monitors and you are using a phone as a source, I would adjust the speaker volume controls (assuming they are present) such that the volume setting of my phone app was close to maximum at typical listening levels.

 

[jacobacci]

Sorry if this was mentioned somewhere in this thread. Does the PO100 work with a USB-C iPhone or iPad connected directly (without inserting a powered USB hub)?

 

[Oukkidoukki]

Sorry if this was mentioned somewhere in this thread. Does the PO100 work with a USB-C iPhone or iPad connected directly (without inserting a powered USB hub)?

Yes

 

[Pearljam5000]

Is the PO100 PRO better than these?

 

[Roland68]

View attachment 500211View attachment 500212
Is the PO100 PRO better than these?

I'm not familiar with the U2, but the U2Pro delivers similarly good results to the PO100 Pro. In a simple comparison, I couldn't detect any difference.
If you don't need the i2s over LVDS interface—which is generally a worse connection option than SPDIF for most DACs anyway—then take a look at the PO100 AK. For a small additional cost, you also get a good DAC based on the AK4493.
However, the PO100 AK cannot be switched to UAC1 if needed.