Would each of you state if your experience with variability in mono playbacks happens with newer mono reissues, with older original monos, or with both?
as far as early 50's to mid-60's Classical and Jazz, and a few pop/rock; they are simply better in detail, dynamics, and natural ambience than a stereo cartridge playing the same Lp. in my system; when i use the 'mono' button on my darTZeel preamp with a stereo cartridge playing a mono Lp i cannot hear any difference (or have not so far).
even very good stereo cartridges tend to sound a bit bound up and bunched together in the middle. the Mono cartridge presents the musical components in a more natural space from speaker to speaker. there is an openness and freedom to the music. i don't want to go overboard in representing the overall presentation; 'better' in this case does not approach what the best stereo recordings can do in terms of space; but the music is well communicated.
i have quite a few mono reissues including all the 45rpm AP and Music Matters reissues. those are also mostly better on the mono cartridge in the same way. i have a bunch of the mono Super Analog Disc Decca reissues which are uniformily better with the mono cartridge.
i am in the early stages of my relationship with mono Lps and so i expect to attain further truths about this subject. will more expensive mono cartridges take me significantly further in performance? will i still be loving monos a year or two from now? or will it be a passing phase?
those are still questions.
stay tuned.