I think I understand the intent of john1970's post regarding the importance of the speaker system. (and it's interaction with the room, I might add..). It is, after all, the acoustics that determine the frequency balance and over-all 'personality' of the sound of a hi-fi system, and the speakers should be chosen carefully as they ARE the most influencial.
I would, however, argue against the 'source' being last in the pecking order. I would argue for the quality of the source being second to the loudspeaker/room interface; with amplification being a close third. Purely from a frequency response perspective, most amplification will play what it is fed in terms of frequency response. It's the resolution and detail that separate the 'best' from the merely 'good' when it comes to amplification. (along with other spatial, power, and ambiant characteristics...)
I used to think that most digital sources sounded the same. And at the lower end of the spectrum, they mostly do. However, the improvement in sound between an entry level NAD player and an entry level Rega, Naim, or CEC player is profound. The added cost for a better source will have a more sigificant impact on sound accuracy and satisfaction than the same added cost for amplification. (most of the time....

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(IMHO, the source has an even greater impact with analog than with digital

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eric the red: congrat's on the Jupiter. nice player.
WEEZ