Preamp for Marantz PM 10

Thinking of giving a preamp to my existing Marantz PM10 integrated amp, which allows preamp input.  Does it make sonic difference?  Saw an Krell  KRC-3 within my budget.    Music a First is also on my list.  Any advice or inputs are welcome.  Thanks in advance:)
I am going to give this a try on mine as well.  I have an McIntosh C50.  Curious.
The C50 also has a sub out connection (PM-10 does not) so I can hook up my JBL 1500 Array as well...…..we will see....