Tube Pre-amp Suggestions.

@kds Since you seem to be pretty open to possibilities, what about an Audio Research REF 75 stereo amp plus their REF 3 preamp?  A guy in CAN has both here for sale.  They are already at reasonable prices and he is accepting offers.  Both of these items are classics and will always have resale value.  Depending on where you negotiated the sale, you could very likely always get your money back if they weren’t for you.  If you aren’t familiar with Audio Research tube power, those 75 wpc would essentially have the same output as your current CODA 400wpc and also most likely be more musical.  I compared my REF 75 to a McIntosh 450wpc amp and they had the exact same output with the REF75 being more musical.  I tried a CODA amp one time compared to my REF 75 in my system and it did provide more control in the bass but overall I found it a bit on the bright side for my taste.  It was an older model and less power than yours so definitely not making a judgement of CODA, just ARC tube power v/s solid state.  The REF 3 pre pairs perfectly.  If you don’t like the black handles, I didn’t when I owned this exact pairing, you can easily remove them and paint to match.  It was a basic Krylon color that matches exactly.  You are in a fun spot with growing your system as amps and preamps are easy purchases and sales so have fun and good luck!