MONO records actually sound wonderful. Good MONO pressings have depth perception that is sometimes better than its two-channel (stereo) counterpart. The resolution in general is very good. Part of the reason can be traced to learning curve. When stereo first came out, recording and mastering engineers had gained expertise at making MONO recordings. Highly skilled mastering engineers came of age a decade or so later in the seventies and beyond. Also, music arrangements in the era of MONO recordings was simpler and some would say genuine (as compared to more contrived and electronic). This then required less tracks and more headroom for music within the recording. Additionally, recording equipment at that time used tubes, thus their effect in the sound recording chain. The key is to play these records the way they were meant to be played - via a MONO cartridge. You will hear less noise and experience the excellence of MONO recordings in the manner that they were meant to be heard and enjoyed.