[raketenmann]

Hey there audio nerds!

I just jpgraded from the DX160 to the DX170. The main reason was that the DX160 had issues with tidal.

So far - so good. Since I use the play both mobile and on my hifi system, I switch between phones out and line out often. But also with the 160 I was confused: it doesn‘t matter what mode I choose I always have a volume slider. Shouldn‘t abline out mode completely bypass all modules that can controll volume and be a fixed level (and as I think hifi standard is +4dB, right?) so is this a real line out and does switch to it give me any benefit?

2nd: on the 160, when i switched at least the olayed was able go have two independent volume settings. E.g. switching from line to phones, the volume dropped from 100 to 50, around where I left it last time. The DX170 doesn‘t seem to do so. Any ideas why snd if this is an option somehow?

Thx for clarification and inputs!

 

[waveSounds]

The line out functions like a pre-out, so it will always be adjustable as it doesn't have fixed gain settings, like some A&K daps do, which lets you adjust for devices that require lower input voltages (as the line out is 3.2 volts at 100 volume). It is still beneficial to use over the PO function as I believe (although might be wrong) that the amp section is optimized differently between the two.

It does remember your volume settings between PO and LO, but will only switch to the LO volume once something is connected to save your iems and ears from getting a nasty surprise should you forget to change back to PO. As an example, if I disconnect my headphones and change to LO, the volume will remain in the PO volume until something is plugged into the 3.5mm port, and if you're using LO and unplug the jack it will switch back to the PO volume even if it is still set to LO.

 

[raketenmann]

The line out functions like a pre-out, so it will always be adjustable as it doesn't have fixed gain settings, like some A&K daps do, which lets you adjust for devices that require lower input voltages (as the line out is 3.2 volts at 100 volume). It is still beneficial to use over the PO function as I believe (although might be wrong) that the amp section is optimized differently between the two.

It does remember your volume settings between PO and LO, but will only switch to the LO volume once something is connected to save your iems and ears from getting a nasty surprise should you forget to change back to PO. As an example, if I disconnect my headphones and change to LO, the volume will remain in the PO volume until something is plugged into the 3.5mm port, and if you're using LO and unplug the jack it will switch back to the PO volume even if it is still set to LO.

Hey @waveSounds
Thank you for your reply. OK, now I undertsand that the volume only switches when I connect something. That behaviour was different with the DX160 I believe....

OK, so the thing with the controllable preamp level makes sense - but what doesn't make sense to me: the max. gain seems to be the same in LO or PO mode. And if there's a power amp that can drive all sort of headphones, then in bypassed mode the gain should be lower - or not?

 

[waveSounds]

I can't pretend I know the engineering decisions, or the even the differences, behind the LO and PO functionality. If you look at the specs of both in the manual they slightly differ in crosstalk rejection and THD, but the numbers appear to be negligible (-113Db and 0.00035 THD+N for LO and -115Db and 0.0004 THD+N for PO). I guess at the very least they provide the two individual volumes so you're less likely to put the full 3.2 volts into your iems. Plus more of the modern amps these days accept or require the higher input voltages to function at their best so the choice to adjust is a benefit. I do prefer A&K's implementation though where you can choose from preset fixed values 2Vrms, 4Vrms etc, but it's never really bothered me.

 

[raketenmann]

Ok. Si I understand now. But to be honest: i don‘t hear a differenece on either output. And from the specs the crosstalk rejection is even better in headphone mode, it doesn‘t really make a difference to change the output mode when connecting to my hifi system. I can also raise the level on my receiver…