This was an amazing and unexpected experience....
I already had my college dream system. Marantz 2285 amp/preamp. Heathkit equalizer and graphic processor that I built, monster cables, Sony linear tracking table, and JBL L65 speakers.
I bought a Conrad Johnson PV 10A preamp off of Audiogon. It wasn't very big or impressive looking, but it used vacuum tubes....
Luckily, my Marantz allowed me to plug in the PV 10A into it and thus bypass the internal preamp within it.
OMG. Night and day difference in the quality of the sound coming out of those wonderful L65 speakers! I was blown away! Then my quest began to upgrade my entire system to what I call 'entry level high end'. I'm very pleased with the outcome, although it took many years to configure and it did cost a lot of money!
I eventually sold that PV 10A to another Audiogon member....