Adding tubes to integrated setup

Hi.  New here. I have a Yamaha A-S801 integrated amp.  I have been under the impression it cannot act as a power amp alone.  I have been considering adding tubes to my setup and came across this on PrimaLunas's site that talks about mixing tubes with solid state:  https://www.primaluna-usa.com/mixing-tube-gear-with-solid-state

Does this  mean tubes can be added only to a solid state power amplifier or that they can be added to a solid state integrated amplifier as long as it meets the 10x impedance requirement?

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You can include a tube component into virtually any system, into any position, with no limitations.   There is only one area that you need to keep in mind.  Running a tube preamp into the small handful of the solid state or tube amplifiers that have an input impedance that falls outside the norm.  We're talking about maybe 1% of the amps out there. 

Don't get stressed.  This is easy stuff.  All you have to do is look at the owner's manual or spec sheet on your amp and you will see something that says "Input impedance".    

If you are adding a tube preamp and hooking it up to an amplifier, the input impedance of the amp should, in general terms, be ten times (or more) the output impedance of the preamp. If it isn’t 10X, or maybe it’s close, you may still get incredible performance."