Best Preamp - NO preamp... (?)

For me... bypassing the preamp has always been my "sanity check" for what the preamp is really doing, or not doing for me.  I've never heard a preamp be MORE transparent than NO preamp.... but it often adds a little something here or there that is desirable..... but of course it's still a necessary part of the system.   So you just gotta find one that has colorations that YOU like or that work in your system.   To this day.... I still have not found an AV pre/pro that I like better than my old Anthem AVM-20 for it's analog pass-through.  I've tried 4 different $2-3k pre-pros whose analog performance was terrible..... just to convince myself that i was not crazy.... I plugged my Oppo blu-ray directly into my amp.. and it sounds GREAT...... therefore.... I know for a fact that the analog pass through of the new pre-pro sucks.  My Anthem is not perfect... but it does sound very good.

Each to their own, it depends on you ears, your pre amp. Some preamps are great others disappointing. I use a number of different ones in different systems. My Yamaha c2a is an example of a good preamp. It's fast yet has a degree of warmth and solidly .  System component matching has lots to do with results too- some good components just don't get on sonically yet others  do. Cables can be another question - just be careful handling them. 

Passives of good quality are now being touted as being as good as very expensive active preamps if not better. Taking it one step further if your amp has sufficient gain, going direct can be surprisingly good but as you mentioned, you lose the ability to switch between components The best thing to do is experiment as you're doing and as suggested above, go with what sounds best to your ears

I think what you've just demonstrated is that your system has a very good gain structure. I was running my Oppo BDP105 directly into my mono blocks too for a while as it sounded better than going through the Octave Phonomudule preamp. I built a passive using Slagle autoformers and the sound is somewhat the same, maybe a touch sweeter. 
But it's all about the gain. That's why it doesn't good to go direct with most people's systems. They don't have enough gain, so they need an active pre to help the signal along. 

They don’t have enough gain, so they need an active pre to help the signal along.

If it goes loud enough for you, you have enough gain, a passive preamp will NOT compress the music if it’s up near full.

Quote from Nelson Pass:

We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.
Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp.

Cheer George