Dumb question......why do you need a preamp?

@troutbum If you have an integrated amp you may not need a preamp.

But a preamp can be very useful if you have monoblock amplifiers. The reason is simple: the longer the speaker cable, the less resolution and impact you'll have out of the speakers.

Monoblocks allow you to keep speaker cables short. This might mean you have to run long interconnect cables to the amps. But if you have a good preamp, and especially if it is balanced line, that's no problem and you can have no loss in resolution or bandwidth doing that- no downside. A good preamp also reduces artifact you get from interconnect cables (usually this isn't a problem in an integrated amp).

Integrated amps usually trade off some sonic performance for size. You can see where this is going: the best systems often use monoblock amps with a preamp.

A good hybrid integrated amp can have a nice active tube line stage. Mine happens to have one employing a nice separate power supply and tranny for the preamp section. Very little sacrifice and in some cases none! It depends on the design of the integrated amp and the use of short signal paths.

Yes, monoblock amps can indeed have a sonic advantage. Not simply because you have a separate chassis, rather that plus the design. Some stereo amps can sound as good or better than monoblocks depending on the design. No absolutes, but rather case by case…..

With the advent of GAN and chip amplifiers one can certainly fit a good active, tube line stage in a nice integrated complete with extra shielding! I can see Ralph of Atma-Sphere building a great sounding integrated amp with an active tube linestage and his Class D Gan output in one larger chassis. I am sure it would compete with many expensive separates. Will we see that soon Ralph? 🤓

Another thought on design and options for sonic purity. My integrated only has one input direct wired to the tube stage. Bypassed the selector circuit as I only need one input for my dac. This is another step that can deliver sonic benefits. Again, for today’s digital only systems not requiring multi-inputs or phono. Ralph that would be a nice option for the digital purist. One last idea. Please no more fuses. Simply have the on/off switch be a magnetically controlled circuit breaker of high quality. Another nice gain in sonic performance.

I don't understand the OP's original question. If you own an integrated, why would you need an integrated?  

Some people like a preamp even with an integrated because they want to use room correction like DIRAC