DAC as pre amp

Theoretically, every component in a system causes coloration. I suppose we all have a preference about how we'd like it to sound.

There are always good and poor examples of every design approach, so exceptions occur.  What I'm saying is that it seems that more preamps currently do a satisfactory job of overcoming whatever obstacles are posed by the signal and the amplifier load than DACs at this point in time.   That could certainly change in the future.

I have had the same experience as the OP. In my case I have a somewhat vintage (late 90's) Krell KRC-2 pre. My theory is that the volume control quality likely has something to do with the superior sound in a pre. We do most of our listening at lower volumes where the line level signal is severely attenuated. A good pre and its volume control are optimized to insure that there is no deterioration in the sound at lower levels. A DAC is really a line level component and the volume control is not critical to its function. In fact, many DACs have digital volume controls that reduce the resolution as the volume is lowered.

I recently purchased an Okto Research dac 8 stereo that is surprisingly good when used as a pre into my amp. This wasn’t as much the case with my previous dac. Even though it still presented well enough on its own, doesn’t hold a candle to the Okto overall (whether as dac or dac/pre). Really does boil down to design, quality of output stage and voltage.

I still overall prefer using my SPL Elector before the Okto, which brings more nuance, timbral delicacy/transients and depth of stage to the presentation. Still very curious what a different amp might bring in a direct configuration, however.

I have been very very impressed with the EAR Acute used as the Pre Amp with EAR Power Amplification and the Acute couples extremely well with Sansui Valve Power Amp'.

How this marriage would produce a sonic, especially in relation to the attractiveness, if adopted for other Power Amp's is an unknown to me.

@carlsbad2 - it doesn't necessarily follow that people who have a large sum of money invested in a preamp are blindly biased. Arguably, those are the people who would have the most to gain if they could simply run their dac into their poweramps since they could junk their preamp and use the funds to upgrade their system.