Sound quality impact - preamp vs power amp?

In building custom audio components I have mixed input about this.  IMO unless your speakers require a specific power amp (horn speakers don't need 200wpc, as an example), then here is my overall comments:
They both offer sonic advantages - in building a Class A hybrid power amp, I thought that it was the better of the two options.  In making a few design changes to our high end tube preamp, I am not sure what I would consider having over the other.  Putting a gun to my head, I would probably at this time look for the best power amplifier since the amp works and sounds so good with other preamps we have tested it with.  Our preamp does add beauty, soundstage dimension, and clarity in direct comparison to other preamps we have compared it to with the amplifier though.

Happy Listening - you are probably more confused now!

OK, so the upshot of all this is a balanced approach.  It's counterproductive to split your funds, say, 20/80, favoring either component.  Evidently, both can have a major impact on sound.  Pre-amps can often cost a little less than power amps, particularly if the latter are expensive, so I wouldn't exceed a 40/60 split, if you're looking for a rule of thumb.

Pre-amp is the heart of your audio systems all the devices are connected to it except the Power Amp. If the Pre-amp is highly transparent the other pieces tend to fall into position better.

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Equal. However, most modern amps have enough gain that they can be driven by the source components (assuming decently sensitive speakers), so a good amp only needs a passive preamp with quality input switching and volume control. So start with a good amp.

Yes, everything gets connected to the preamp but all signals eventually make their way to the speakers. The speakers are the heart of the system and have the greatest influence, especially if they’re decently efficient.