I have a RMS 191 and matrix MTX 191 (not A). In SM mode does not work well and OK in XY. I sent it to Neumann customer service here in Madrid (Magnetron), and they sent to Neumann in Berlin. After two months they return me not repaired properly, continuing not work well in SM mode.
What is your recommendation, return it to customer service or buying a new one, the MTX 191A?