Importance of Amplifier versus Preamp?

therefore the question becomes: for a limited budget, I have looked and purchased vintage equipment because the idea was that the vintage equipment was better engineered/constructed that a lot of equipment made today, for 1/10 of the price of today equipment.
As far as the polk speakers,should I get other speakers? what do I need to look for. Just so everyone remember,at my age, my auditive range is probably 90 % of what it was when I was 20, so my ultimate goal is a sound that is clean, with an emphasis on mid range, and just enough bass to be balanced. Hope this make sense.
Speaker specs: Monitor 75 T/•1-inch (25mm) silk/polymertweeter/•Four 6-1/2-inch composite drivers/frequency response:30Hz - 25kHz /
thank you for your input.

We can't hear your system. Turn it up some! :^)

Seriously, have you done everything you can to get what you have set up best? Have you started to listen critically? How does it sound? Does it need to change? If so what are your goals for the sound that are not being hit currently?

Gotta know the goal first. Its hard to offer totally reliable advice over the internet without the ability to hear the subject. Even if someone had the same combo of gear in exactly the sme working order, every room is different.

One thing for sure, its best to try to always try to identify the weakest link make one change at a time, and take time to evaluate well before doing anything else.

Vintage gear may offer the best value in some cases but not always. It all depends.....

The Polk web site specs that speaker @ 90 dB (hopefully per watt per meter, but no detail) and the nominal impedance as 8 ohms. Without seeing the impedance curve, it's hard to be sure, but it's likely that it would be a good candidate for moderate powered tube amplification or solid state. If vocal/midrange is a priority, an EL-34/6CA7 tube amp with 2 tubes per channel that operated in ultra-linear mode, or maybe a pair of KT88 or equivalent per channel.

If it seems like I am pushing tubes, you are right. If the speaker has been designed to be compatible w tubes (see my post above) then I think they sound most like real music. YMMV.

I believe much of the "importance" of the preamp ideally would be seeking its negation as a separate component. I'd try out a fully integrated solution like the Devialet 120, or carefully seeking the match a power amp with a combined DAC/preamp. Especially with a sole digital source it'd make more sense.

Your list of the equipment you presently have includes two preamps, one of which can accept a coaxial digital input as well as analog inputs. And your CD player provides a coaxial digital output as well as analog outputs.

So the system can be configured in at least three different ways:

1)CDP analog outputs to Sony Esprit preamp to SAE power amp to speakers.

2)CDP analog outputs to Nikko preamp to SAE power amp to speakers.

3)CDP digital output via a digital cable to Sony Esprit preamp to SAE power amp to speakers.

Have you compared sonics for each of these configurations? It seems to me that the existence or non-existence of differences, and their magnitude and character if there are differences, might provide some clues as to what the weak link in the system may be, from your individual perspective.

Also, after doing some research on all of the components you listed, while I certainly can't definitively pinpoint a weak link, I'll say that the SAE power amp and the Sony Esprit preamp seem like impressive beasts relative to the other components. And although on many occasions here I've cautioned people against assuming a high degree of correlation between performance and price, I think it's noteworthy that those two components sold for well over $1K in 1980's dollars, while the Nikko sold for less than 1/4 of that amount around the same time, and the Yamaha sells for $300 today.

Provided that you have confidence in their condition, and pending your answer about a comparison between the three configurations, and given your $1500 budget, my instinct would be to direct the investment to something other than a replacement for the SAE and the Sony. So in addition to the possibility of a speaker upgrade, you may also want to consider a CDP upgrade, including the possibility of one having a tube output stage.

And one thing I would most certainly NOT do is choose how to allocate the $1500 based on generalized notions of the relative importance of preamps, power amps, or other kinds of components.

Good luck, however you decide to proceed. Regards,
-- Al