Connecting a DAC directly to an amp?

Have looked into a Barrett preamp $9k which shuts down tubes while doing ht bypass.  Barrett may be a great box and only 2 tubes and other fancy circuitry that avoids need for more tubes.  but more tubes would seem better.
Absolutely insane why tubes in a great preamp like arc or many others, can’t be designed to allow shutdown during ht use.  Sooooooo stupid.  Sooooooo many users would love this.

so I may have to live with more frequent tube changing and higher electricity costs to have a great tube preamp all ready to go at a moments notice.  

" Absolutely insane why tubes in a great preamp like arc or many others, can’t be designed to allow shutdown during ht use. Sooooooo stupid. Sooooooo many users would love this. "

Really, if soooooo many users were clamoring for this don’t you think they would do it. The market for stereo preamps isn’t for home theater. Give it a rest

As with so many of such questions, the answer is: "It depends..." 

1) If the DAC uses digital means to volume control (bit stripping) it is of course possible - but particularly at lower volumes, the SQ is affected negatively.

2) If the DAC volume control is of top quality *analogue* design (and how many actually are?), it becomes a question of how much better a/any preamp's volume control AND overall design implementation is.

Starting with a very clean powersupply, a volume control (not really by potentiometers), sealed relay source switching, plus a separate or well screaned power supply etc.

3) If such a preamp is used, the general finding is, that the inclusion of such, using reasonable good IC's connecting the lot, the result in the cases I know of, including my own, will result in higher SQ.
M. 🇿🇦 

I run my Monarchy NM24 direct to the LTA Z10 amp; sounds better than with an additional pre-amp.

I experienced big improvement in SQ when my Teac NT-505 was connected to Modwright LS-100 preamp rather than straight to the amp connection.