There are a few things you may want to consider.

First of all, you need a phono preamp for ANY cartridge, because one of the main functions of a phono preamp is equalization. When music is processed for record master cutting, the bass is severely de-emphasized before making the master, and the treble is also changed in level. This is called RIAA Equalization (look it up on Wikipedia for a full explanation).

Thus, to play back music as it comes off of the record without going through an equalization circuit would give you garbage; no bass and weird treble response. The phono preamp restores the music's original frequency response.

Any way; there are phono preamps that are for MM only, and there are those that will also work for MC cartridges (which have less output and the preamp has to amplifiy it more).

I suggest that you get one that will work with both. The Musical Fidelity V90-LPS is around $200 and is excellent.

1950-1980 receivers/amps usually have a PHONO input, which means that a phono preamp is included within the unit, but if so it will be for MM only. For a MC cartridge you would still need to go through an external phono preamp and then into the AUX input of the amp/receiver from the phono preamp output.

As far as the LINN is concerned. They are very fiddly; you need to become an expert Linn setup and modification mechanic to own and operate one. I would not recommend that route. They are not "plug and play" units like most turntables. I think they are a major pain in the butt and not worth the hassle.

There are many excellent turntables that are not fiddly and will work great without all of the hassle that owning a Linn involves.

I would recommend the Music Hall 7.1 or the VPI Scout. For a cartridge, I am partial to Micro Benz cartriges. The Benz MC GOLD is $600 and is really excellent.

I use the 7.1 with Benz cartridge in a high-end system and am very happy with it; hard to beat at any price IMO.

If it has two phono inputs, one of them might be switchable internally to use it for either an MC or a MM cartridge. You would need to pull up the owner's manual and check that out in detail. I have seen that on a few older units. Or both of them might be MM only.

The built-in phono preamps of amps may sound good, or they may not; only comparison with an external one will tell.

There are many excellent MM cartridges, so you don't have to go to a MC anyway. Some prefer them; some don't. Check out the cartridge selection on Needle Doctor.

There are some tube phono preamps, but they are not always better-sounding. In general, they do not impress me. I have an Audio Research LS26 system preamp, and it uses tubes, and it is superb, but tubes are not always better.

I used to have an Audio Research PH5, which was a tube phono preamp that cost $2000, but the Musical Fidelity M1 LPS is what I use now, and it sounds significantly better (it also only cost $450). It is solid-state.

The Bellari is OK; I think either of the Musical Fidelity preamps are better.

The analog (speaker) output jack of most computers can be connected to the AUX or TAPE input and work OK.

For my computer table I just have a pair of Audioengine 2 powered speakers connected to the "speaker" output of the PC. That works very well.

On the other hand, you might or might not get better sound quality by using the USB output of the computer and going through a different DAC and into the amplifier.

If you run short of inputs on the amp, you can get a switchbox and connect it to the Tape Input and use it to switch between several inputs.

The one I like is the Cables To Go #28750, which Amazon sells for $19.95. It has 4 inputs, so instead of only 2 general-purpose amp inputs you would have five available by using it.

I looked at the manual for that MAC preamp, by the way, and neither phono input is set up for a MC cartridge; MM only.

Congrats on the Mac equipment! My MC7150 is in the shop right now and I will be very sad until it comes home! The Klipsch Chorus speakers that you procured have a sensitivity of 101 db, so I don't think you will have any issues with the amp driving them. Let us know how you like the sound when you get her all set up.