xDuoo TA-20 Plus Tube Balanced Headphone Amplifier - Powers on and produces sound. - Constant noise on the R (right) channel (symptoms like white noise/hissing. Occurs regardless of volume). - The issue was not resolved by replacing the vacuum tubes. - L (left) channel is normal. - This product is for those who can attempt repairs, use for parts, or try to improve the condition through environmental adjustments. Accessories include the power cable, instruction manual, and box. Due to the current condition with the noise issue, this is considered junk and sold as-is. Please purchase only if you understand the condition. Returns and claims are not accepted.