amplifiers tube vs. solid state

As @mulveling mentioned… check the input impedance of the existing SS amp, and the output impedance of the candidate tube amp.

I run a tube pre now (one from 98 to 2022, and a different one since last year.)
Sonically they are similar.

I have run them into tube amp(s), Class-AB and Class-D and they all were pretty well behaved.

I encourage you to track down a copy of Roger Sanders white paper - something like tubes vs. solid state. You can find it on the sanders sound systems website in the technical papers section. It's an excellent paper and he makes things very easy to understand.

@hershey2010  I have been wondering the same thing about my system. Currently running both SS pre and amp but was wondering in going with a tube amp. I really like the idea having best of both worlds I would think to start of that route is to go with a tube pre with a SS amp. 

Not sure of ur budget, but the Berning inspired Linear Tube Audio might be your ticket.

As to reliability I think that thee late great Tim de Pavaracini said that power tubes have a great lifespan. I spoke to him and he said 300B's should be used in a push-pull configuration - never single ended - yes they can sound good but it kills those tubes. I just nodded along - frankly i have never understood amp topology properly save to say i know it from the blurb but can't build a circuit myself.

@hershey2010  I have been wondering the same thing about my system. Currently running both SS pre and amp but was wondering in going with a tube amp. I really like the idea having best of both worlds I would think to start of that route is to go with a tube pre with a SS amp. 

It depends on what the “best of both worlds” is.
My tube preamps were not “Tubey”, but my tube amp certainly is more along those lines…

The good tube pre amps range from low distortion to tubey, and I mainly got rid of sibilance when I went from an 80s SS pre to a 90’s tube pre.

If one like tube distortion, then that is a different path than I was going down.

So it takes some understanding of what is the desired outcome, and what equipment gets on there.

I am not sure that the OP’s ML preamp is going to improve with a tube pre. It could be a sidestep.
I also am not familiar with the OP’s SS ARC amp.

Both would seem from the glance to not be in great need of upgrading.