How much do I need to spend to get a preamp that sounds better than no preamp?

“No preamp” is a straight wire. It will add no noise, no distortion, and in 99.9% of cases no frequency response anomalies.

There is not a preamp made that has the same characterics. Thus, there is no amount of money that can be spent on a preamp that will sound better that a straight wire.

It is now easy to see that the above post is false. Its based on the idea that cables have no artifacts, also leaves out the effects of capacitance and the like that are inherent in cables and makes the false assumption that a volume control is somehow the same as a straight wire, which it certainly is not! As a result, you can actually have an active line section with wider bandwidth that can indeed sound better than a passive and not due to ’pleasant distortions’ either (since any properly designed active line stage will have vanishingly low distortion), but instead due to the additional transparency offered by cable control. The distortions created by amplifiers are far more significant!

It’s always nice to have something to argue against, but in my case, you are setting up a straw man consisting of a passive volume control and a high impedance output to the next stage. 
My volume control is the internal volume in the JRiver Media Center 64 bit DSP. My DAC has a volume control, but I keep it at 0 dB attenuation. The DAC has a low impedance balanced XLR output that goes directly into my amplifier. So while you can make good arguments against passive volume controls and uncontrolled cable interactions, these are not a factor in my system. Thus, in my system, my statement above that there is no amount of money that can be spent on a preamp that will sound better that a straight wire, is a perfectly true statement.
 I also think that the distortions caused by active circuitry are far more likely to cause audible problems than a passive volume control hooked up to a patch cord. Though that isn’t an argument that can be settled without specifics which are not available here. But I feel that I am on pretty solid ground in saying that anyone hooking their moderately well-engineered DAC up to their amplifier without any passive components between the two will get better sound than they would get by adding an active (or passive) preamp to the mix. This will be the case for most people, and was the scenario painted by the original post.

So while you can make good arguments against passive volume controls and uncontrolled cable interactions, these are not a factor in my system. Thus, in my system, my statement above that there is no amount of money that can be spent on a preamp that will sound better that a straight wire, is a perfectly true statement.

@phomchick I agree on the first sentence 100%. But not on the last; most high end audio manufacturers don't support the balanced standard even though XLR connections are used (and to be perfectly clear, I'm not sure whether that includes Oppo). So if you were to add a buffer or active line stage that *does* support the balanced standard, you *may* find that it is an improvement.

If you have to audition the cables to get it to sound right, that's a clue that the balanced standard isn't supported.

Maybe it's time to try an integrated?

Perhaps. I have.

@honashagen   Given the excessive (intrathread) amplitude, are you any closer to an answer? Thanks.

You must spend $9347.87 to sound like no preamp do it asap!!