Hi, I can make the description only from my memory (sold it sometime ago), and also, I had another headphones with Master 19 (GL2000, AQ Nighthawk), so it is not very valuable. But I was generally satisfied with M19, I used it as preamp with Audio GD power amp at first and then as HP amp. The sound was warmer and smowhat softer, the S17 pro is a little bit cleaner, and has sharper edges, bass area is much better from S17 pro (tighter, more detail). The M19 should be great with brighter HPs. M19 has a really great realay exponential volume control, usable also with sensitive IEMS (much better implementation, than S17 pro), so it is better as a preamp. There is a very good video on YT from MidFi Guy - M19 with Burson soloist, violectrics ans some other amps comparison... look at it, I agree with his description. For my ears (from memory) the s17 pro is better choice in all areas, except the volume implementation...