Connecting a DAC directly to an amp?

@shkong78 

I connect Dave and HMS to Line Magnetic 508 pre input....It is working well....But I have Schitt Freya pre between Dave and my headhone amps to connect 20 ft balanced cables.

The Freya seems like a well-designed, simple preamp to provide high quality volume control with buffering or gain as needed between a DAC and a preamp.  I understand why you would use it to drive 20 ft interconnects.  Have you tried using it in your other system before the Line Magnetic 508 to compare whether it improves the sound vs. DAC-direct?  

I am curious because I previously thought I needed a buffer between my volume controlled Metrum Adagio DAC and my amplifiers but this weekend I rearranged my system so the DAC is close enough to the amplifiers that I can use 1M (XLR) interconnects.  At this length, it seems the buffer may not be needed for the same level of dynamics and tone although I am still evaluating. 

This is like groundhog day for me.  After going a week running my DAC directly into my amplifiers using relatively short 1M interconnect cables, I continued rearranging my system layout and reintroduced my buffer/preamp between the DAC and my amps and.....Shazam! Technicolor!  Better soundstage depth, better body, deeper tone, more impactful and deeper bass, and a more realistic and less electronic presentation.

It seems this happens every time I try to go without my preamp/buffer.  Maybe it is my SMc monos, which have input impedance of only 10K ohms, but it was also like this with my former Clayton amplifiers (but maybe not as profound an improvement), which had input impedance of 100K ohms.

The other thing I did was replace my well-regarded Oyaide power cords with 7 awg NOS Western Electric cords and wow, an immediately noticeable kick in the pants.  The amps are 650 wpc and are each run from their own 20A dedicated circuit.  Going from 10 awg to 7 awg made a substantial sonic improvement.  I don't typically notice huge improvements from cables and tweaks but this one was substantial.

Guys,
The Adagio does not bit strip, the volume control operates by changing the reference voltage so is not actually in the signal path.  The minus 10dB is optioned by a switch on the back and I do not have that engaged.  I am hearing the same thing I heard when comparing the same gear DAC direct vs. through the preamp/buffer into my Clayton M300s, which had an input impedance of 100K ohms.
We could argue about whether I should hear it or not, or whether it is because of the amps, but it doesn't change what I consistently hear.  To be clear, the sound of the Adagio directly into the amps is really good, but it sounds better through the buffer/preamp first.   
The input impedance of the amplifiers is just another example of why it is important to understand your gear and how it all has to work together.  Regardless of the input impedance, the amps are the best I have owned/heard out of some very well regarded amps such as Lamm M1.2 Reference, Clayton M300s, Heron M1As, and Acoustic Imagery NC1200 amps.  Virtually any active buffer or preamp will have a low enough output impedance to easily drive those amplifiers - a small price to pay for the best sound I have heard in my room.