Tube Pre-Amp, vs Solid State with Tone Controls/EQ to take edge off the top end?

Don't tone controls introduce phase problems? Simple circuits mitigate phase problems?  And how does one detect how much phase accuracy influences realism in the sound reproduction.?

Generally speaking, its best to avoid ...
using Tone Controls unless it is a well-reputed high end audio piece. 
Luxman, BAT, etc

I thought Pass made an Integrated 250w amp?

--SimAudio, they make high-end integrated. 
--Rogue Audio, Vincent Audio: both great 
--Quad: came out with a 80wpc (gorgeous) tubed integrated about 8 years ago or so. 
--oh, NAIM! the SuperNait II or maybe they have another high-ender now.
--Pathos are well regarded hybrid tube/ss integrates. Great for most all types of music. But you may want to Bridge their amps, which I've read is the way to go.
Hard to tell since you said you would not reveal the speakers. 

But lets get back to the basics: dirty electricity and distortion.

The lesson learned here is that using cleaner electricity UP FRONT and better POWER CABLES up front that run from the wall into a power isolator (I use a Pole Pig- 8 ports) and/or a conditioner (I use a Shunyata hydra 2port). 
- I heard improvements with every up grade.

**But what really blew me away was my last change:
Changing from a respectable Belden ethernet from Blue Jeans Cable to a Wireworld Starlight into the ethernet renderer.

**After I changed to the Wireworld, all and all grain went way.
The soundstage grew larger, while the musicians came into much better focus, and the PRAT just snapped into place. 
So I cant blame the amp or speakers anymore. 

@almarg for the win!  I was reading through this post, thinking a DEQX would solve this.  I too faced the same issues with “awkward” high end frequencies, too bright, but not consistent.  I say “awkward,” because the high end wasn’t consistent on every type of music I listened to.  Sometimes it would be inline with the overall track and other’s it would sound “excited” and cut through the rest of the music.  Sometimes it wouldn’t be enough.  I thought, ok, it’s got to be the room.  Had GIK Acoustics build a room treatment setup, based upon my room dimensions and outputs from REW (Room EQ Wizard), which helped, but there were still some weird high frequencies popping through.  I toed the speakers in, moved them away from the walls, spent a couple months monkeying around with placement.  Then thought, must be the tubes in my preamp.  Bought NOS Mullard’s, frequencies still there.  Additionally, I had an entire Shunyata setup, power cables and conditioning, then someone recommended a DEQX.  Solved.  And when I say solved, I mean, it elevated the entire musicality of the system.  They are pricey, but can be had on the second hand market and there are folks on here that really know how to squeeze the most out of a DEQX.  

Best of luck in addressing it.

Hi , I purchased a Schiit Loki 2 weeks ago . Not a perfect solution , but very versital and worth buying . Running a Rogue RP-1 with Telefunken G-73R ( 12AU7’s). Switched out my Had Inspire for some heavily modded Dynakit MK III’s . Tone was hollow and lacked bass . Tried 4 different speakers and even tried NOS GEC KT-88’s . Sounded like crap . On a whim I took a vintage Marantz 2226 and used it for a pre with tone controls . Huge difference ! Hum and hiss decreased dramatically. Hollow tone went away .  So I purchased a Loki . Went back to the Rogue . So Schiit Yiggy to Loki to Rogue to Dynakits . Works great . You’ll need an extra pair of Interconnects of equal quality to what you already have . As far as SS to Tubes or visa versa , I prefer SS pre to tube amp , YMMV.  So I am considering trying a Schiit Freya now . Also when I run high efficiency speakers the hiss is not present with the SS pre . I also don’t feel that I’m loosing any of the tube magic , even with a pair of 12AU7’s that fetch $400 each at Tube Depot ( mine were sourced somewhere else for much less ). If I ran a Mac , I would consider Amarro software for its digital tone prosser . But try the Loki , you’ll probably keep it as I did . Happy Listening , Mike.