Need advice on a turntable question

Replacement was a must. The dealer did not do his job in aksing you questions on what you would be using a new TT/Cart with. The dealer should have dug deeper. Sold you what was in his stock, not what you need!

What is your old TT?

The 2M Red is a really good-sounding cartridge for a MM and will outperform most others out there. The Pro-Ject table should be able to extract everything it has to offer. The comment about your old ML1 is a bit biased as it was also a nice piece, then or now. Depending on your speakers, you may just be hearing a different sound balance than you're used to or you may have a misaligned cart. Check it with a protractor to be sure. If you're still unhappy, complain to the dealer and get them to give you a different preamp to audition for a week or so to see if you like that better.

Well, electronic parts do deteriate over 35 yrs so not total BS.

My original turntable was a Lux 441 which, back in the day, was an excellent turntable!

I have about 5 hours on the Ortofon cartridge and the ArtCessories Pre amp and after 20 hours I will make a decision on whether to have the Ortofon removed and the Denon 103S installed and go back to using the ML1 but at this point the Ortofon cant come close to the Denon sound! The Denon had far superior bass and a much better defined mid range and high end.The Ortofon sounds like there is a veil between me and the music in the mid & hi end.I am sure that Ortofon makes much better sounding cartriges than the Red but that Denon has a great sound.If I find that my Denon has distortion in the treble range or distorts in high volume passages that will mean that the rubber cantlever support is brittle and I will buy the new Denon replacement for the 103S called the 103R.

How do you know it's not the TT difference you're hearing? What are the reviews on the Ortofon?

'The Ortofon sounds like there is a veil between me and the music in the mid & hi end.'
This could be what is known as skin effect and it's one of the possible side effects of a moving magnet cartridge but it doesn't have to be.
It simply sounds like this cartridge preamp combination isn't working for you. I have an ASR phono stage and I believe that either the ASR Mini Basis or the ASR Basis Exclusive can turn any rag tag cartridge into to a silk purse. Zed Hussain is the ASR distributor and he'll offer up a discount. If this is still too much to spend, than I'd ask the dealer to offer up a good priced phono stage or preamp that will load both mm and mc cartridges.
I can't understand why the dealer would stick you with a preamp that will only accommodate a moving magnet cartridge, especially if you prefer a moving coil cartridge to begin with. Also, Levinson makes good electronics so there may be some things that could use replacing but its not absolute. The Levinson may just need an overhaul.