Whoa, I lost track of this thread and there's some misinformation here.
*Modern mono pressings are pressed like stereo pressings--horizontal modulations for one channel, vertical modulations for the other channel.*
Modern mono pressings are microgroove with groove walls at 45°. Unlike a stereo pressing, each groove wall is a mirror image of the other.
With this in mind it's easy to see the advantage a mono cart has in playing such records. With a stereo cart there are output differences between channels which should be identical playing a mono record. A mono switch will blend these differences, not eliminate them. Any alignment, azimuth, anti-skate etc. imbalance will smear the signal.
Elimination of vertical noise is a great advantage with a mono cart as Johnnyb says. This can be dramatic with some older or beat up records. For microgroove mono you will have a similar advantage with advanced profile tips as with stereo. Ortofon, Lyra, Soundsmith make some mono carts with extended contact tips.
Conventional MM/MI, manipulate the connection of the coils to eliminate vertical output. MCs do so with the orientation of the coils and armature. According to AT, the MONO3 and 33 have identical construction style which results in 30dB of vertical rejection @ 1KHz.
AFAIK AT never made a mono MM.
The microgroove was invented in 1948 and adopted mostly through the '50s. Pre microgroove pressings from the early '50s or before might sound better with a 1 mil stylus. LpGear still has the Ortofon OM D25M with 1 mil tip. I've never used it, but Ortofon has it listed in their historical data as lateral output. You might be able to use other OM styli as well.
*Modern mono pressings are pressed like stereo pressings--horizontal modulations for one channel, vertical modulations for the other channel.*
Modern mono pressings are microgroove with groove walls at 45°. Unlike a stereo pressing, each groove wall is a mirror image of the other.
With this in mind it's easy to see the advantage a mono cart has in playing such records. With a stereo cart there are output differences between channels which should be identical playing a mono record. A mono switch will blend these differences, not eliminate them. Any alignment, azimuth, anti-skate etc. imbalance will smear the signal.
Elimination of vertical noise is a great advantage with a mono cart as Johnnyb says. This can be dramatic with some older or beat up records. For microgroove mono you will have a similar advantage with advanced profile tips as with stereo. Ortofon, Lyra, Soundsmith make some mono carts with extended contact tips.
Conventional MM/MI, manipulate the connection of the coils to eliminate vertical output. MCs do so with the orientation of the coils and armature. According to AT, the MONO3 and 33 have identical construction style which results in 30dB of vertical rejection @ 1KHz.
AFAIK AT never made a mono MM.
The microgroove was invented in 1948 and adopted mostly through the '50s. Pre microgroove pressings from the early '50s or before might sound better with a 1 mil stylus. LpGear still has the Ortofon OM D25M with 1 mil tip. I've never used it, but Ortofon has it listed in their historical data as lateral output. You might be able to use other OM styli as well.