ST Modular SUM stereo mixer eurorack module

ST Modular SUM mixer. Stereo mixer with 5 channels with mute, EQ and Send. Extra stereo input and stereo send return. Important to note that this mixer has an inherent design flaw that results in a noisy headphone output (high pitch noise). I've installed the mods that ST Modular suggested might fix the problem but the noise is still there, at least in my system. Other than this issue, the mixer works and sounds great. Cosmetically, there is a scratch on the front panel near the 4/5ch send knobs.