Man, after so much research, I feel like it's not worth going for a portable amp/dac for & 100 or under. Got a lot of great suggestions but I'll just get a cheap, beginner friendly non-potable amp/dac I guess. Anyone have any suggestions? I think the sabaj D3 looks pretty good in this range. I mainly wanna run my Zs5 and Philips shp9500. Apparently some have a bass boost button, that would be preferable since I suck at EQs (I'll also use zs3, and the plethora of chifi iems with them)
Also, does anyone have any experience with the Syba Sonic SD-DAC63057?
@hakuzen loved all you're suggestions, but I guess I had to sacrifice portability for maximum sound quality. So is the sabaj D3 a good choice? I mainly wanna run my Philips Sph9500 with bass boost and my Zs5 with extra oomph. I also looked at the Syba Sonic SD-DAC63057, it's got those bass/treble/mids switch. Dunno if it's good tho, but it's only around 40$.
Lastly, would a fiio k1 be a viable option? I hear it's not that good, but thought maybe, if I get a good deal, I'll go for the k1+sabaj d3
sabaj da3 is also a portable dac, like da2 and fiio k1. they all get digital via USB (input) and convert (DAC) to analog sound which is amplified and goes out through a 3.5mm stereo jack socket, where you plug your head/earphones.
that's way thy are known like "DAC/Amp", because they convert music from digital to analog and then, gets amplified.
but none of them have an analog input to amplify an analog signal. unique input is usb.
so k1+da3 has not sense: they are the same thing.
the difference between them is that da2 and da3 have quite better specifications (noise, distortion, etc.) than k1. difference between da3 and da2, is da3 has an alternative balanced output.
despite of their size, all of them can drive your phones perfectly by their own.
which use can you do of these DAC+Amps? you can connect them to the USB of your PC or of your smartphone (USB OTG cable in this case).
a pure and single headphones amplifier has got an analog input (3.5mm stereo, for example, where you plug in a cable from the stereo output of your pc/smartphone/DAP) and an analog output (to plug your head/earphones), basically. it doesn't convert digital to analog audio (that must be done in your pc/smartphone/DAP).
if the DAC of your pc/smartphone is crap, a DAC+Amp like da2, da3, k1 is a solution.
if the output impedance of your PC/smartphone is high (>1ohm) and/or is using coupling caps, a DAC+Amp but also a single headphones amplifier solves this.
if your smartphone doesn't provide enough audio power to drive your phones, a headphones amplifier but also a DAC+Amp(if enough powerful) solves this.
if your player (DAP) doesn't provide enough audio power to drive your phones, or have high output impedance, or coupling caps, a headphones amplifier solves this.
the fantastic thing of da2 and da3, is they have better specifications than many pc soundcards, and than most smartphones audio's.
the downside of using a dac to replace the dac of your smartphone, is that you have to install drivers (not a problem), and that many smartphone apps are not able to send the output to the usb (using these drivers). so you end using audio dedicated apps (not a problem either).
the problem with single headphones amplifier is that we are looking for enough powerful, output impedance <1ohm, no coupling caps, low noise and distortion. and there are no so many. btw, have you checked fiio's pure headphones amplifiers?