How does it compare to the M15i in terms of sound quality and amplification power without taking the price into account?
Maybe DMS could chime in since he’s so fond of the original?
At half the price of the M15i and apparently the same internal components, besides the change in DAC chip from ESS to CS, it could be the best M variant Questyle has released so far, especially because Cirrus Logic is known to sound more natural.
I’m personally very partial to Cirrus Logic chips since to my ears, the most natural and linear sounding Pro converter, the Lynx Aurora (n), including their Hilo interfaces, uses a CS chip in it’s design. Although I’m not sure about the Hilo 2 anymore.
Haha, I was just coming back to say this might be just what you were looking for. Reportedly it doesn’t need the usual headroom since it’s designed around current-mode amplification and stays linear all the way up to the top, so it doesn’t run out of steam for the last 3-6 dB like most voltage-mode amps on the market. So even at only 3.5 Vrms and pushing the HD650 to only 114 dB max it would still cover all your needs just as in NwAvGuy’s old “pure loudness-based” power recommendations.
FWIW, I’ve been looking more into the actual user reports about the original’s power delivery and found this one apparently very respected chi-fi reviewer (and admin of a chi-fi group on FB) is on record saying the original M15 can power 300-ohm headphones and IEMs “easily”, but also a 14-ohm 93 dB sensitivity IEM still “easily”. But then over time the same guy went on to repeat to people that “it can’t push hard to drive headphones”, and when I pressed him about that, it turns out he has nothing but the worst of the worst inefficient examples as things the M15 couldn’t power. https://www.head-fi.org/threads/earbuds-round-up.441400/post-18388371
Which makes it weaker than an endgame desktop DAC-amp, but who was really expecting that in a dongle this year?
For my part, I’m ready to believe the official specs that say the power of the 15C on SE-out is the same as the older 15 and 15i, and the power on BAL-out is double, so the only thing stopping me from getting it is that report about its tonality being perceptibly different from the 15i toward the warmer. I need things brighter, as I think that’s where I will find fidelity in terms of flat response (KA17 fails that test).
