stereo cartridge on mono record

Hi Eldartford,
you say:
>>> It is essential to remove sensitivity to vertical modulation by jumpering the two channels together, or using the MONO switch on your preamp (if it has one). <<<

Any idea at all, why when I use that 'summing' to mono on my ML326S (with phono) the level drops by at least 3dB? I seem to get rid of that "vertical noise" but also loose resolution (using a stereo MC).

as Samujohn says:
>>> Despite theory, I generally prefer the sound without engaging the mono button. <<< Could it be because of what I mention above?

I'm sure that the 'jumpering' must work as Eldartford
says, but brother ---- that's a pain, if you do not have a lot of MONO to listen to.
I have a suspicion that if the phasing L/R (due to stereo cart performance) is not at it's best, the summing will cause some signal cancellations and that would explain the drop in output level, correct me if I'm wrong.

Thanks,
Axel

samujohn is correct. this is a case where 'a problem is invented or exagerated to provide a grand solution'.

Jaybo...If you had ever listened to the L-R signal when a mono LP is played you would not call the problem "theoretical".

By the way, you might try listening to the same L-R signal from a stereo FM radio broadcast. The L-R signal is separately broadcast as a FM signal between 20 and 40 KHz, demodulated, and mixed with the L+R mono signal to get L and R. This scheme only works well with a very strong RF signal, which is why in weak signal areas FM mono works fine but stereo is lousy.