The Yamaha MG12XU is a 12-channel analog mixer with USB connectivity and FX return. Due to its many features, not all functions have been tested, but basic operations such as sound output and the built-in effects were confirmed by connecting microphones to each channel via XLR. There were no particular problems. Also, I didn't feel any scratchiness on any of the channels. However, the fader on channel 2 is slightly higher than the other channels, but this shouldn't cause any problems during use. Also, the fader on channel 4 has a slight catch. I purchased this used and have been using it for several months without any issues. ■ Type: Analog Mixer ■ Mono Channels: 4 ■ Stereo Channels: 4 ■ EQ: 3-band (mono ch), 2-band (stereo ch) ■ AUX SEND: 2 ■ Group (Bus): 2+2 ■ Digital Effects: 1 (24 types) ■ Dimensions (W x H x D): 308(W) x 118(H) x 422(D) mm ■ Weight: 4.2kg ■ Accessories: Instruction manual (copy), AC (three-core) cable Thank you for viewing.