+1 on what EHart has said,
I have been down this road as well, I used a Marantz 2245 as a pass through pre when i first got into hifi, I realized very quickly that a dedicated preamp makes a world of difference. There are several options depending on what you want to run. You can pickup an older adcom, emotiva, hafler parasound to even a McIntosh for relitivly cheap, I have seen mx119 and C26s go for 600 bucks which is a steal as they are really good preamps that will last you, just becarful with the choice as some of the mx series does not have a phono stage if you into vinyl. The MX series are home theater preamps but works just as good for 2 channel audio. If you are looking for more, I recommend the Usher 307 but it’s pricy, one thing you can count on is higher end preamps will not color your audio, like a lot of the lowerend gear will. E bay is a great place to look for solid preamps.