Not just bad, but really terrible. Anyway, the machine is not what it promises and I bought it just to see if it's worth it. So, let's go. The amplifier is based on two pairs of tip41c + tip42c transistors (one pair per channel). These transistors are commonly used in the audio field, but not for main amplification, only for pre-amplification. The fact that they are used here as main amplification is simply tragic. The real power of the amplifier, exactly at the clipping limit, is 2x48 watts at 8 ohms, 2x65 watts at 6 ohms, and 2x85 watts at 4 ohms, which is not much for this machine. Additionally, it is completely unprotected, meaning no soft start, no protection against DC, and no limiter (I'm asking for a lot). Of course, the machine doesn't heat up, but it also doesn't produce enough power to warm up. Also, when the peak lights come on, don't push it further with +15% overdrive, as it distorts harmonics by 10% THD. This distortion can translate into an extra 20 volts or even 10 volts of continuous current at the output, enough to burn even the best professional speaker. Guys, I mean it, this machine is dangerous, it's a death trap. Just like the label says, it consumes 180 volts but outputs 1000 volts, how is that even possible? Seriously, guys, since we haven't found an amplifier that is 500% efficient yet, this amplifier is a terrible machine. And the design of the circuit board is awful. Here, the board says input 27 0 27 volts, but the transformer is 34 0 34 volts. WTF? Yeah, I'm right. In conclusion, if you want an amplifier for relaxed music that can kill any speaker, go for it. But if you want something better for this price, build your own with 30 euros. It's that simple. Update: I bought a board based on two pairs of nice Toshiba 2sa 1943 and 5200 transistors, which fit perfectly and require almost no modification to the machine. The performance has improved dramatically if you have the appetite and know a few things about electronics.