Mix a naim and non-naim pre- and power amp

I am actually looking for a phonostage, however, the local Naim dealer always reply pending for overseas shipment.
My Naim combo is Naim NAC112/NAP150/FC2, for stageline (~USD275), I need to buy extra cable (~USD125) to FC2 which makes a total of USD400.
As stageline alreadys include one cable, theorically, around 60% of the money goes to cable.

This makes me think of a similar price 2nd hand pre-amp (preferrable tube) for phono, using its tape-out to Naim NAC112.

The tube-preamp gives me upgrade flexibility instead of a pure stageline2 phono amp. And I guess phono section in the 70or80's amp should be good as LP is the major source at that time.

Its a pity non-naim preamp cannot connect to NAP150 as I read from the unofficial naim audio forum saying that cannot mix non-naim preamp with naim power-amp as naim power amp require a particular type of band limited signal which all naim preamp provide via a suitable filter.

By the way, what model of Naim preamp or int-amp is having phono. I can search for a 2nd hand although 2nd hand Naim is rare in my country.

I listen Classical music, mostly violin/cello/piano concerto. Any comment to my 'strange' idea?

Thanks in advance.