Hello, I'm totally new here at this forum and in audiophile sphere. I have a favour to ask you. I want good portable system for listening music. Because I do not know how the music should sound I want something really good to be a reference for me. I have Audio-Technica ATH-M50x but I feel I need better headphones so I have ordered Shure 1540 because I read very positive feedback here on the forum. I lack low bass with m50x. The source is Sony Xperia Z5 dual. I mostly use Spotify with extreme streaming quality but I will use TIDAL and experiment with lossless formats. The sound with Z5 -> M50x is not very good. The sibilance is very noticable for me and the bass is not low enough I think. When I plug the headphones to PC, the sibilance is not so significant. Reading some forums here I found out I need external DAC/amp. This is why I post here. I want to ask you for recommendation of really portable nice sounding DAC/amp. When it comes to size, it should be somethink like flash disk and it should be plastic because if I put it to the same pocket as my smartphone I dont want the dac to scratch my phone. I found this candidates: HiFimeDIY Sabre Android DAC FiiO K1 STONER ACOUSTICS UD120 HiFimeDIY Sabre U2 Asynchronous USB DAC Zorloo ZuperDAC Audioquest DragonFly USB DAC Preamp Headphone Amp Version 1.2 Audioengine D3 Portable DAC & Headphone Amp Geek Out IEM 100 USB DAC LH Labs Geek Out 1000 DAC/AMP LH Labs GeekOut V2 USB Headphone Amplifier & DAC Geek Out 450 USB DAC and Headphone Amplifier I read K1 is battery draining. ZuperDAC looks like metal. When I read reviews of DragonFly I was disappointed because people dont talk about it in a good way very much. I do not need slight improvement. I want to get from my headphones the maximum. I dont need the best but I dont want only slight improvement. And definitely I do not want sibilance. I am sorry I post it here. I did not find a way how to create new thread. Could you tell me which DAC is good for me and if I need amp (if so, I want amp integrated in DAC - not separate device)?