I do not know how the M15S EQ settings look like, but generally when working with any EQ you set the "Pre-amplifier" or "Pre-Gain" to a negative value (equal to the highest positive value of your EQ settings) to avoid clipping in the digital domain. Since a 16 bit PCM music file is just a...

The software used to update the firmware also shows the current version, so you can check it there without updating anything. In the menu it only shows the date of last update, not the version, which I agree is a weird choice.

I got a similar message on my iPhone initially. Just turned the "Phone mode" knob on Q15 to "On" position, and it started to work (after reconnecting). Without the phone mode Q15 will try to drain the phone battery, so the phone says it cannot provide enough current to Q15 via USB/Lightning...

Did you change between USB and BT when listening to the same song? There is a glitch that reactivates PEQ and thus applies a negative pre-amp value making the sound quieter.

Certainly worse than wired, but according to these tests AAC implementation on iPhone has an equivalent performance to LDAC 990. On Android and even MacOS, the AAC performance is much worse. I personally find AAC (from iPhone) sounding alright, cannot really pinpoint anything wrong or missing...

The one with MQA on is the correct level. The reason it's quiter with MQA off is because PEQ is engaged (and has some default negative preamp value). Try to click on "Bypass" option. If it does not increase volume, select some other profile and then select "Bypass" again. When you turn on MQA...

If one looks for the most analog sound, try the Super Slow Roll-off DAC filter, it attenuates high frequencies the most and has the best impulse response from phisical perspective. It was meant to emulate the sound of old R2R NOS DACs, known for being analog sounding. I personally think the...

Both Audeze Euclid and Campfire audio Supermoon are sealed planars. I personally couldn't find a good seal with the Supermoon, but heard from many people that they listen to them in noisy environments without issues.

AFAIK, they were using knock-off Knowles BA drivers produced by Bellsing in the Solaris. Not clear who makes the planar driver inside the Supermoon. Some claim it's the same driver as in the 7Hz Timeless, considering extremely similar tuning and physical characteristics (albeit CFA put some...

I use Neutron Player (paid) on iPhone. It has a PEQ, as well as an access to the entire AutoEQ database of PEQ profiles. However it does not scrobble to last.fm, so I mostly try to tip roll instead of EQing.

For me, it was the absence of desktop mode or at least a straightforward way to change a battery. I already had my experience with Hifiman R2R2000 DAP where battery life went from 8 to 3-4 hours in 1-2 years, so this time I went with FiiO Q15 instead. Similar features for almost half the price...

Noticed a small bug: when switching from bluetooth to USB the sound becomes much quieter. Going to PEQ, changing to e.g. Jazz, and then back to 'Bypass' makes it as loud as BT. PEQ is on 'Bypass' on both BT and USB. Not a disaster, but somewhat annoying to spend 10-15 seconds to fix it every...

In case someone finds it as interesting as me, here you can see pics of a complete device teardown

I would also like to see the desktop mode added. PEQ would be a great addition as well. Meanwhile, since it can be used while charging, is there some kind of battery overcharge protection? Or ideally an ability to set charging threshold? Otherwise if you keep it connected to a laptop, the...

Both of them exist of course, but the question is what do you measure to stabilise the amplifier: Most of the amplifiers, at least in portable gear, are negative feedback amplifiers based on op amps: that is a part of the op amp output is fed back into its input with an inverse phase to...