Mono LP's?

No and yes.

No you don't have to play mono recordings with a mono cartridge.

Yes, playing mono recordings with a mono cartridge will sound better.

A simple fix: Withstand the use of a mono switching on your pre-amp and with a stereo cartridge on you TT just get two single ended 'y' adapters one with male stereo RCA's and one with female stereo RCA's. Connect them so that the two single RCA ends plug into one another, taking the stereo output of you TT and "blending" if you will the two signals together and then exiting as a two channel output of mono from the other end going to your pre-amp. This is essentially what Eldartford mentioned, I believe. It will effectively cancel the vertical groove modulation and render your monaural vinyls far more quietly.

Happy Listening!

If you use a stereo cartridge you need to jumper the left and right signals, preferebly right at the cartridge. However, if you also play stereo LPs it is more convenient to do this in the preamp with a switch. DON'T do it at the power amp output!!

What this does is eliminate the cartridge's sensitivity to vertical groove modulation, which in the case of a mono recording is pure noise. Some cartridges sold as "Mono" are actually stereo models with the jumper installed internaly.

Old records, especially 78 rpm ones, should be played with a larger "needle". Some cartridge mfrs. offer such stylus for their stereo cartridges.

Cool thanks all. Got it!!

no..its no big deal

Only to play them at their best. For me, the Sumiko celebration works fine on mono lps and can only imagine how much better it could get. My phono stage has a mono or stereo switch so that takes care of any problems down line. Some preamps also have a mono switch, a neat little item that should be more common

No.

You can play mono lps with a stereo cartridge. The reverse, however, may not be true--some mono cartridges would be, at best, hard on a stereo LP.

Mono cartridges are of interest because they can offer better performance for a mono LP since they are designed for the specific task. IA mono cartridge should pick up less surface noise, and offer overall better performance. However, the downside is that it costs more--between $50 and $100 on up for the cartridge, and you need to have it set so it's either on a removable headshell or on it's own turntable. Thus, if your mono lp collection consists of two or three records, it's probably not worth it. But if you have a large collection, it could be a good investment.

There is a good review on Audio Asylum about one mono cartridge. (http://www.audioasylum.com/cgi/m.mpl?forum=vinyl&n=265943&review=1)

Mono cartridges are available. You don't have to have a mono cartridge to play a mono LP.