no worries @mistermonitors we are not born with obscure knowledge about audio equipment
You can have a preamp and amp, but at your price range, an integrated is better (Rotel)
Just as a clarification
NAD 2400 Power Amp
NAD 3020 Integrated
NAD C270 Power Amp
NAD C370 Integrated
Rotel Ra- 1062 - Integrated
Nothing on this list is a preamp. You don't need a power amp for an integrated. An integrated is a whole package, a power amp is redundant
It sounds like whoever wants to sell you these NADs is pushing hard and totally confused you..