could you kindly also get into the differences between attenuation and amplification? It seems hard to get across that most dacs only need the former whereas adding a pre by definition adds distortion.
@antigrunge2
The problem we're all up against is that Redbook requires for more voltage than any power amplifier would ever need. So the signal has to be attenuated to do any good.
That means that in the case of a passive the control value becomes critical. Lower values like 10K work better, but most sources won't support driving 10K- they are more comfortable driving higher impedances. This can result in a loss of bass and distortion on the part of the source if its having issues.
Active preamps do indeed add distortion. However they tend to be less susceptible to interconnect interactions. There are four functions that any line stage should have:
1) volume control
2) input switching
3) supply any needed gain
4) control the interconnect cable to prevent interaction
Of these the 4th is least understood in home audio but well understood in pro audio, which is why they can use inexpensive cables and still get neutral sound.
If the active line stage is good at controlling the interconnect cable it stands a very good chance of being more neutral than a passive device and possibly also lower distortion, depending on the passive device to which its compared.
So its a mixed bag, which is why this conversation persists.