What is most important part of a system?

One thing for sure.I sold audio for years. By far the most distortion is your loudspeakers. Even 1-2% is far more than any other piece of equipmrnt.That is where probably more money should be spent to get the highest quality.  Your sourse for sure is the most critical for precision 
Of the event.  Everything starts from the sourse and detail once lost 
Cannot be made up else where that is why  you should get the best turntable 
Including Arm  and cartridge and sound Different this includes Digital .Makes sure it's sonic signature is a good fit before pulling the trigger.

IMO, the pre-amp is the heart of any system. Some will view this as the most important.  After the pre-amp, Speakers are on-deck.

Happy Listening!

I think I'll buy one of those T-shirts that says:

IT'S THE TRANSDUCER, STUPID!

What is most important part of a system?

I remember reading someone saying that the most important part of a system was the source. I thought "Wrong! Speakers are the most important".

Now, I have changed my mind. Source is the most important part.

You are correct, it all starts with the source, get that right 1st (digital or analogue) and your 1/3 the way there. If not right, it’s a never ending battle to get the truth, and everything after it becomes just a band-aid fix.

Ivor Tifenbrun (Linn Sondek)

Cheers George

Here is one of several prior threads in which this question was discussed:

https://forum.audiogon.com/discussions/most-important-components

Following is my answer as stated in that thread:

Do not expect any consensus among the answers which will be provided, or among the answers that have been provided about similar questions that were asked in the past.

Some will say the source is most important, because its shortcomings cannot be compensated for by any of the downstream components. I dispute that rationale, for two reasons:

1)That logic ignores the DEGREE to which different types of components may have shortcomings.

2)The source can't compensate for the shortcomings of the downstream components either.

Some will say the speakers, because in general they (and their interaction with the room) arguably make the biggest difference in the character of the sound that is heard.

Others will say the preamp, contending that it is "the heart of the system."

My own answer, expressed in general terms, is that a chain is as strong as its weakest link, wherever that link may happen to be located in a particular system.

And more specifically my own perspective leans in the direction of "speakers first," but to a greater or lesser degree depending on how "important" is defined (especially the degree to which price is reflected in that definition), and depending on whether the source is analog or digital, and depending on the degree to which the particular listener values deep bass extension and the ability of the system to handle recordings having particularly wide dynamic range.

Regards,
-- Al