Just catching up on the thread, and have a couple of comments:
First, the battery indicator on my QP1R still works fine after getting it back from repair last July. When I sent it in, it read 100% at all times, regardless of the actual state of charge. The repair was well worth the trouble in my view.
Second,... I don't want to start any conspiracy theories, but on the subject of firmware version 1.09 vs. previous versions, and with regards to maximum volume limits: I keep thinking back to the Stereophile magazine test report of the QP1R.
https://www.stereophile.com/content/questyle-audio-qp1r-hi-rez-portable-player
I wonder if Questyle might have made a modification to the maximum volume limit in the latest firmware, in response to the maximum volume clipping issue raised in the Stereophile test report? It's just idle speculation on my part, and I have not the means, or desire, to test this in any way.
I do think that with the change from 60 volume steps to 120 steps in version 1.09 that, say, half scale volume seems to sound a dB or so lower than previous versions. But bottom line, it is not an issue in my usage because I can't listen to any of my headphones (Etymotic ER4S, AKG K701) with the QP1R near maximum volume anyway, with any firmware version; it's just too loud. With version 1.09, I turn the volume to whatever volume level sounds good, 65, 70, 75, whatever. I don't know what to say if the QP1R needs to be maxed out to drive a particular headphone.
From Stereophile Dec 2015 issue:
"Fig.7 shows a spectral analysis of the Questyle's output while decoding a full-scale 50Hz tone. The volume control was at its maximum, and when I looked at the oscilloscope screen, the top halves of the waveform were beginning to clip, which is why a picket fence of low-level distortion harmonics can be seen. Reducing the volume by 2.5dB eliminated the clipping, and now only some odd-order harmonics are visible (fig.8), with the third the highest in level at –104dB (0.0006%). The distortion was even lower with DSD64 data (fig.9). Intermodulation distortion was also extremely low, even with the volume control set to its maximum (fig.10).
image:
https://www.stereophile.com/images/1215Questfig07.jpg
Fig.7 Questyle QP1R, volume control at "60," spectrum of 50Hz sinewave, DC–1kHz, at 0dBFS into 100k ohms (left channel blue, right red; linear frequency scale).
Read more at
https://www.stereophile.com/content...table-player-measurements#Wj7pvtqdZxrpxegT.99
1.0.9
