I agree with mrdecibel here. I would try the Freya in "passive" mode to see if you like the sound and to see if it is similar to running the DAC/phono direct to your amp. That would give you an idea if a passive preamp would work for you, though I don't know that any other "true passive" would really be better than the Freya. There are some passive preamps that have more than just a volume control and add things such as output transformers that can change the character of the sound - this gets into the exotic passive preamp area.
Another idea: It's about a $600 investment test, but you could try putting in a quad set of PSVANE CV181-TII tubes in your Freya. That would definitely increase the resolution and quality of the Freya, but like any other preamp, it will still not be the same as direct/passive. Although, many preamps will add a "magic" to the sound that can be desired
Cables - the extra set of cables between preamp and amp could also color or slightly the sound as well.
Another idea: It's about a $600 investment test, but you could try putting in a quad set of PSVANE CV181-TII tubes in your Freya. That would definitely increase the resolution and quality of the Freya, but like any other preamp, it will still not be the same as direct/passive. Although, many preamps will add a "magic" to the sound that can be desired
Cables - the extra set of cables between preamp and amp could also color or slightly the sound as well.