Pros: Small, Loud, Clear, Tube/Valve, 3 Band Passive EQ
Cons: Only Passive Cooling, sometimes gains a little static
I don't have much to compare it against especially for headphones or as a preamp. I have used my Beyerdynamic DT860 headphones on my PC for a while and talked into getting a tube amp from a guy at my work. I thought I would try something cheap to get the idea of what a tube does to music. This one seemed decent and the other models had good reviews so I liked the idea of a EQ and purchased this one.
At first when I unplugged my headphones from my PC (Motherboard Sound card unfortunately, hope to be getting something more shortly) and the tube amp in with my headphones now connected to the tube I was surprised. I thought the music seemed muffled yet very little bass.
I was told to let it break in for 30-40hours. I let it play about 10hours before listening to it again so my ears wouldn't acclimate. It sounded more tinny now and I tried giving more bass with the EQ on winamp or with the passive EQ but it would just distort. It did sound better than my previous listen but that's not saying much.
I now listened to it again at about 25 hours after letting it play over night. I was surprised how it had changed from what I remembered. I swapped the headphones between directly to the PC and through the tube amp. The tube amp was much less muffled than before but still had a mellow and tinny sound compared to the PC directly.
I listened here and there constantly letting with a play list of jazz, piano, orchestra, background chatter, a thunderstorm, sine sweeps, and silence for rest.
At about 50hours this thing has really opened up. I left it with the same comparison song, same cords, computer and headphones during all of this for fair comparison. I now hooked it up to my phone and laptop. It gets loud, stays clear with a mellower sound, and has made my headphones sound amazing. I didn't even know they could play such a range of sound and had been debating selling them before this to get some Sennheiser HD650's. I am no longer dissatisfied but still want the HD650's. I thought these headphones couldn't provide bass but I was wrong.
Now with almost 80hours on it, the sound has improved even more especially with Jazz and Orchestrated music. The 3 Band EQ is amazing as well. I can give it a little more bass or a little more mid or even some treble with ease depending on the song I am listening to or game I playing (yes I now listen to everything through it). I am very glad I did not cheap out $10 and get the one without the EQ. I am thinking about trying different tubes just to see the difference but overall very pleased with my purchase.
I am going to be doing some testing with my earbuds soon on this as I have just wanted a fair even comparison. I would always 0 out the EQ before comparing as I wanted everything to be identical except run time.