Why do I need a preamp?

I’m running a Vega DAC direct into a Pass amp with balanced interconnects. DAC level is set to maximum. and I'm controlling volume through JRiver/JRemote. There are no other sources. I’m happy with this sound quality.

Some people say this is wrong and I need a preamp. I don’t understand how adding another device into the signal chain can improve SQ, even if the the preamp is completely neutral and doesn’t inject its own sound.

If anything, I had thought about a passive pre like a Tortuga which is generally accepted as being pretty much dead neutral, but not sure why I even need this.

Maybe it is that you don't need a preamp. If you don't plan to have any other sources, you might be just fine.

One concern might be that the DAC, although balanced, might not support the balanced standard. That is a common problem in high end audio. The point of the standard is to eliminate cable interactions with the system, so you will know that there is a problem if you can hear differences between interconnect cables.

This **could** be solved to some advantage by a preamp that does support the standard, but IME high end audio preamps that support the standard are few and far between!

Another concern is how the volume control functions- as in: does it cause audible loss of resolution at low volumes? This is an area where an analog control can work a lot better, but FWIW, IME the JRiver system works pretty good.
Checkout  'Bascom's Preamp Chronicles' in the PS Audio forums.
They discuss this topic in detail, and I find it interesting as their  DirectStream DAC has a good reputation for sounding great when used direct to amp.

I added a Sim 740P preamp to my system (Berkeley Alpha Dac2 then replaced by Sim 380 DSD) and with the preamp in the system the space around the instruments and vocals along with the 3-d realism of the music is the best I've ever heard in my system.   

I agree though, adding the cable plus the cost of a very good preamp is crazy compared to the price of a good DAC used direct.  My preamp cost 2x my DAC and all I use it for is volume!!
That being said, I can't imagine not having the sound I now have with the preamp in place.

I did just read a review of the new Hegel HD30 DAC and the reviewer used a 740P preamp and said he thought the HD30 actually sounded better than used with that great preamp.   So in that case paying so much for the preamp makes no sense; but, at least once you have the preamp you don't have to worry about your next DAC not sounding great when used direct.   Definitely DAC + or - preamp is a potentially expensive conundrum...


You don't need one.  

Obviously  using a pre amp will change the sound.  Each in a different way that might be better or not. 

So if you want to change the sound a preamp will do that.   

If you had  multiple sources any without volume control you would need at least a passive preamp to provide that.  The preamp would also help all sources sound more similar fbofw. 

If if you had a phono you would need a phono preamp as well.