How to judge a preamp's sound


I just heard a YouTuber review a preamp. He told the audience that he tried it with many amps, and then went on to offer descriptions about "the" character of the preamp (bass, midrange, and treble, etc.).

My question is, Can someone accurately generalize about "the" sound of preamp across a variety of different amps? Wouldn't the amps be enough of a variable to at least complicate the "character" of a preamp? This is a serious reviewer with many subscribers.
128x128hilde45
@teo_audio
Let’s just call it a complex affair that can reach self interpreted conclusions via many different paths.
Everything affects everything so there is no hard set conditionals in any of it.

My limited purpose was to raise for scrutiny a practice -- one metric or method -- which seemed to me to be inherently flawed. I'm no longer sure I was right, given some of the comments above, which are helping me reconsider.

I’m not sure what you mean by "self interpreted conclusions" or "no hard set conditionals."

What seems clear from what people attest to in forums, reviews, and in their living rooms is that some judgments can be made with some level of confidence, despite the multi-variable, relational, and dynamic nature of the phenomena we’re experiencing. Same thing is true with food, wine, relationships...well, everything. We’re in a Heraclitean universe (no stepping into the same river twice) and yet fire burns, sugar is sweet, and metal dome tweeters can be harsh, sometimes.
@hilde45 FWIW even a cable and no preamp at all has a sound unless you jump through some hoops to prevent it doing so.


It helps to have recordings with which you are familiar. I use recordings I made myself (and have the master tapes) so I know how they are supposed to sound. But that is a luxury most people don't have, so start with recordings you've heard many times and then see how changing out a component seems to affect the sound of that recording. In a nutshell, that's how reviewers do it. This is entirely subjective so you won't get 100% consistent results. So a consensus of more ears is also helpful.
@atmasphere Thanks. Those are good suggestions. I imagine keeping the cables the same would be advised in any comparison.

I'm not presently involved in trying out preamps, but I still listen to reviews for fun. I thought I had spotted incorrect advice and was seeking to learn if that was true. 
The idea that a preamp should not have a sound is over simplifying its role.  
Ideally it should not add or subtract from the tonal spectrum and balance of the source but this is not realistic.  Preamps can be evaluated on their tonal presentation and balance and how well the do at the frequency extremes and how transparent and clean sounding it is.  
Also it should not add any additional noise or distortion but again this is not realistic. 
Finally the amplification withing the preamp can be evaluated on its representation of drive and dynamic energy.  For me a preamp should offer exceptional micro and macro dynamic energy.  
Bottom line- a preamp can easily be evaluated on its sound quality when compared against others.  Saying it should have no sound is a gross over simplification and not possible.