Review on Topping L30 Linear Headphone Amplifier NFCA 3500mWx3500mW HiFi Stereo Home Audio Amplifier Earphone Amps Desktop Preamplifier - Blue (New Version) by Marc Gallner

I can't speak for professional users with this amp and I only have two pairs of open backed Sennheiser headphones to try it out but I have heard from other reviews heard of this amp. These are the headphones it's aimed at. The sound through this amp is incredibly clear and can be either really great or very boring depending on your taste. Tested with Sennheiser HD558 and 600 I can say that this amp is definitely overkill for 558 (50 ohms) but the sound is amazing and you can reduce the gain by 9 decibels if you use more sensitive headphones or headphones. .For 600s (300 ohms) this thing gives them a starting boost and while it lacks the bass boost I can get from the FiiO E10K it obviously has a lot more power and the bass seems tighter and tighter despite something, that doesn't ' fully hit. This is extremely important for both aggressive and critical listening in headphones. The size of the amp itself is ideal, but the power cord would be a bit longer. You also can't plug in headphones and line speakers and run them at the same time, not that most people have many reasons for that, but I like it with my FiiO when I'm listening and want to show my roommates I can just turn up the volume on my speakers turn it up and they start playing right away. This is by no means a deal breaker and probably something to ensure the AMP is delivering enough power for whatever endpoint you are using, but it would be nice to have speakers playing in headphone mode without an amp, switching between the preamp and headphones can only change the direction of gain.