Do preamps have a material affect on high level sources?

vjpacor
 It would seem that a preamp is merely attenuating a DAC output. How can it alter the signal?

The fabled perfect "active preamp" sound, has the "the sound of a piece of wire" and it does not exist.

Any active amplification circuit, whether it has gain, zero gain or negative gain. Will have, and add, it’s distortion to what the source originally has feeding into it, and they all sound different, there is no "perfect preamp"

If you feed your source direct into the preamp and it has a digital domain volume control, this is about as perfect as you can get, so long as you don’t "bit strip" with too low a volume setting on the digital volume.


Cheers George

George,
Your response is most consistent with the intent of my question. Thanks. But why then, isn't it common to drive a power amp with the variable analog output of a good DAC?

There are two ways to look at the question being asked, what you measure and what you hear. Different preamps DEFINITELY sound different in the same system. Whether they add coloration, distortion, or whatever else, is a matter of taste and what you like your music to ultimately sound like. The idea of daisy chaining several preamps is simply silly unless you want to show off your equipment rack.
By the way, the topic has previously been discussed ad nauseam and a quick search can/will prevent a long and pointless debate. 

My Benchmark DAC3 L is directly connected to whatever amp I happen to be running.  I also route my Rega RP10/Parasound JC3+ through the analog input to the main amp also.
I have not powered up my preamp since installing the DAC into the system last November.

A good preamp will have very low distortion at the levels needed to drive a power amp and wider bandwidth than the source.

The main things that a good preamp brings to the table is a better volume control than the ones found in most DACs (there isn't a good way to do volume control in the digital domain) plus the ability to drive the interconnect cable to the amplifier properly, so as to minimize the effects of that cable. I've yet to see a DAC that deals effectively with either of these issues.

We sell a lot of our line stages to digital-only people- they run the DAC volume all the way up so as to minimize the the damage done by that control and use the preamp volume instead. The preamp then can drive long cables where their DAC can't. In this way they report that the use of a good line stage is more transparent and more musical- more like real music.


Note my use of the word 'good' above; many line stages are not up to the fairly simple tasks I outlined above, and so do damage rather than help.