shiit Freya+ muffles the base? Recommendation for preamp please

ARC, Supratek, EAR, Atmasphere…

"muffles the base"

That's interesting. But how is the bass?

Are you using balanced or single ended connection?  Those two may be a mismatch, given the impedance matching:

https://forum.audiogon.com/discussions/amp-preamp-impedance-matching-can-anyone-explain

Check the specs, but I think if you use XLR connection you should be okay?

I have always liked the sound of B&W. So I recently upgraded my speakers to 804s.

...Strangely, the bass was not satisfying or full enough for me, even though it is a big speaker.

...Again, here, the bass was the weak point.

...it was the deeper bass that was lacking.

...if more bass is desired, add a nice subwoofer.

....It was only at very loud levels that the bass finally shone through.

...the only area I found lacking was the bass output,

{Editors note- The 804S does not have a lot of distortion in the low frequencies, and depending on what one has listened to in the past, the 804S’ lack of bass may just be a lack of distortion. }

But what the heck, it must be the Freya that is at fault because of reasons and "I have always liked the sound of B&W.".

After all, Freya’s specs are only 3Hz to 200KHz -3dB in tube mode.

Edit - I haven’t seen any test how Freya+ output impedance behaves at low frequencies. I think - and I am happy to be corrected - that this may be an issue with tube pre-amps in general, but depending on design.

I'm not a huge fan of Schiit's stuff.

I think you pretty much have a complete mismatch going there...