It seems it is solid built with quality. During the break in period, this Muzishare R100 amplifier really sounds dull as it lacks of crystal clear treble and has almost no bass. However, you will notice it sounds better and better after 30 hours of break in. At the 50 hours of break in, overall performance becomes warm and pick up all the frequencies. Treble is clear and bass is deep and solid. And now I expect more after 100 hours break in. This amplifier is powerful. I only turn to 1/3 of volume and push my 150W 3 way speaker loud enough in a 200 sq ft room. Overall, I really satisfy Muzishare R100 tube amplifier and I am glad it comes with balanced input. It is a solid built and very good quality product. Also, the seller has fast response to solve my problems. I high recommend.