Best Preamp = No Preamp?

It really depends on your system, with multiple amps etc. I would think a preamp is necesary.
I am using passive preamp but I have very sensitive speakers (horns) and a very sensitive amplifier (low input voltage and very high input impedance) and in my case the passive did beat a top of the line preamp, by a very small margin.
In different cases active preamps do add body and dynamics to the music, but low quality preamps do mess everything up so it is dangerous. One of the most important parts of a preamp is the volume control which can vary in price and quality, I like resistor loaded attenuators, which can be used in active or passive preamps, a bad volume control can destroy the signal!

As always, there is no rule....

I guess the best answer is it depends as always...

Anyway, I just read a couple of manuals of the DACs with volume control.

Both of them kind of claiming that connecting directly to amp and using it's volume control is the best.

I guess for these DACs, better to follow the manufacturer's suggestion?

Benchmark DAC1
http://www.benchmarkmedia.com/manuals/DAC1_USB_Manual.pdf

Bel Canto DAC3
http://www.belcantodesign.com/pdfs/UG_Dac3.pdf

"Direct Interfacing to Power Amplifiers:

The DAC1 USB is designed to interface directly to power amps and powered studio monitors in order to provide the cleanest and shortest path from the digital source to the monitor output. This often results in a substantial improvement in sound quality.

10, 20, and 30 dB pads are provided for interfacing directly to monitors and amplifiers that often have too much input sensitivity to handle high-level (+29 dBu) signal levels."

Above is from the Benchmark DAC1 manual.

A preamp is not needed if the goal is to simply have a way to control loudness/volume. However, if you want it to sound great, the best your system can sound, then to pick up that last 10 to whatever % of improvement you must have a good preamp. Key here is having a good/great preamp. I have always found that a good preamp improves the sound. I have found this regardless of the reference system I had at the time, regardless of how good the DAC or CD player was and finally regardless of the cost of the CD or DAC in question. I have owned the AA Capitole with volume, the Opus 21 with volume etc, and a good preamp always improved the sound greatly.

Only those who prefer a more threadbare or thin sound will go preless. Some do and for them preless is fine. These are the simple facts of this long debated question based on my experience with lots of top end gear and sound systems.

Ha! Have fun and play for yourself.

Bill

I have found the opposite, if you want Body and the absolute dynamics, warmth etc.. Nothing can replace a good Tube Preamp, even no preamp.. Just my opinion, but something is always dry or missing in the emotional connection running digital raw, some super hi end players might put pretty good preamp sections in their top digital pieces that will work well, but I don't feel any DACS in these price ranges can compete up against the equal DAC with an excellent Preamp in the Chain.