I every now and then wonder about the technical side of audio and just wanted to ask a basic question. I just wanted to know why or how the preamp adds/improves the overall sound quality. I remember reading somewhere that it shouldnt add anything and it should be transparent. If that's the case could I just connect my amp directly to my DAC on my PC and just use the volume control on there and have an optimal setup? Rather than spending money on a good tube preamp?
In my opinion I think it would sound better with a good preamp but just wondering more about the reason why.
When you say the following "could I just connect my amp directly to my DAC on my PC and just use the volume control on there", what does "on there" refer to?
If your talking about using your computers volume control then IIRC you cannot use the ASIO or WASAPI drivers in whatever music player you are using, as those drivers lock the volume at 100%.
ALL DAC's (that are DAC's only) dont have a volume control. Using your computers volume control is normally frowned upon since most folks want to use the drivers mentioned above to get the cleanest signal from their computer to their DAC.
DAC's/Headphone amps/pre's (like the Meridian Explorer, Audioquest Dragonfly, Audio GD NBF-5) have the ability to also be pre's in addition to being a DAC.
So anyway you look at it, unless your using your computers volume control, if you have the ability to control the volume, you're using a pre of some sort.
Only other way its possible is if your amp has a gain knob, which is still doing to some extent what a pre does.
An active preamp can provide two useful things beyond their "icing on the cake" functions (balance/tone control, switching, equalization of various kinds or signal processing).
Useful Thing 1: gain
Useful Thing 2: impedance matching between source and power amplifier
Whether you need or will benefit in a net fashion from either of these things is going to depend on your ancillary components, your needs, and your expectations.
For me (at least currently), transparency trumps those things, so I use a "passive preamp" consisting of an autoformer volume control and source selection.
Thanks for the detailed responses that clears up some of the questions I had.