Tim:
You realize of course that your MF A3.2 only has a PREAMP OUT and not a PREAMP IN, so you will not be able to use your MF A3.2 as a power amp with a new preamp.
I learned this the hard way when I purchased a MF CD PRE24 (preamp/cd player combo) to use with my MF A3 integrated amp and wound up only being able to use the cd player portion of the MF CD PRE 24. This led to a purchase of a MF A300 power amp and a sale of a MF A3.2 integrated, when all I originally wanted was a matching A3 cd player, which by then had been discontinued. I had received a great price on the CD PRE 24 (it is in use today with a Prima Luna Prologue Five power amp) and I liked all its preamp capabilities, but I could not use it with the MF A3 integrated.
Why did MF do it this way with A3/A3.2? Because they saw owners using the A3/3.2 with other power amps (like mono blocks)or a HT receiver, not another preamp.
So, about all you can do is change the power amp at this point ... or get another integrated (think Prima Luna Prologue One or Two for tubes).
Regards, Rich