Just got an AMP+ in yesterday from kjdElectronics (authorized reseller for North America), and the build went great; however, I noticed that there is no sound when playing 48kHz material. Sampling rates of 44.1kHz work fine.
I installed sox this morning to verify. This works (I hear the tone):
root@hifiberry:~# play --volume 0.5 -r 44100 -n synth sine 1000
Encoding: n/a
Channels: 1 @ 32-bit
Samplerate: 44100Hz
Replaygain: off
Duration: unknown
In:0.00% 00:00:02.04 [00:00:00.00] Out:86.0k [!=====|=====!] Hd:0.0 Clip:0
However, when I run this command, there is no tone:
root@hifiberry:~# play --volume 0.5 -r 48000 -n synth sine 1000
Encoding: n/a
Channels: 1 @ 32-bit
Samplerate: 48000Hz
Replaygain: off
Duration: unknown
In:0.00% 00:00:02.73 [00:00:00.00] Out:123k [ | ] Hd:0.0 Clip:0
I suspect that this might be a hardware problem, but I'd like to confirm before I send this board back to kjdElectronics for an exchange. I'm currently running DietPi version 147, but I could switch to another O/S for testing. Please advise.
Besides no sound at 48kHz, it sounds quite nice. Here's a photo of it driving an old JBL 4311B studio monitor:
