Preamp - what's the purpose?

I was a complete non believer in preamps. All the while, I was not getting satisfactory results from a Grimm Mu1/MMT front end, with the Tambaqui going directly into my Gryphon Essence amp. Sound was too gossamer, poor dynamics and bass, even bought a subwoofer. After two years of handwringing and tweaking, finally started auditioning pres. Fixed all of my issues. I was looking at moving up the amp chain, etc. Now, I have my subwoofer turned off. YMMV, but the Tambaqui going directly into the Essence, as much as logic should dictate, is not ok.

@ricky64

Very interesting

In my experience a pre is a clear improvement.  I assume there are situations where it isn't but the first time I put one in my system I was close to shocked.  I believe I was running a pair of Classe CA-200s bridged mono in addition to a pair of Infinity Intermezzo 1.2 subs.  All out of a Benchmark DAC1 with the balanced out to the amps and RCA to the subs.  This was around 2008.  I bought a Bryston BP25 used for a grand.  It made the overall presentation a ton more forceful and distinct.  Bass was more distinct and the mids gained a lot of texture.  I assume all the interconnects and multiple components were taxing the DAC output capability beyond what it could keep up with.  The system may have lost a trace of transparency but overall it was much better.  

One day I expect I will have a combination DAC/Preamp form factor from MSB or DCS and do away with the separate pre, dac, streamer, etc.