fish1050
Headphoneus Supremus
I've tried it with several different amps and so far it hasn't affected the sound in any negative way. Ramp the volume on the M1 to 100 and control the output on your amp.
A lot of times double amping causes distortion but I haven't experienced it with this dap.
Actually to avoid potentially distortion, adding noise and over taxing your DAP at 100% constant volume you might want to try 80% volume on your M1. Others more knowledgeable about double amping than me recommend 80% unless recommended otherwise by the manufacturer.
I have been double amping my A17 with the Fiio Q1 for several months now. I started at 90 percent volume (27/30) and slowly began reducing the volume on my A17. I found my sweet spot for the best sound at 22/30 on my A17 with my Q1 between 4 to 6/9. I still get plenty of power but I find at this volume I get a smoother slightly warmer sound that I like. Obviously results will vary so nothing wrong with a little trial and error. Also consider that running your M1 at max volume will give you the least battery life per charge and could reduce the life expectancy of the battery and your M1.