[Puma Cat]

Originally Posted by ylee

For most of my audiophile life, I viewed preamplifiers as complex switching devices that allowed easy selection of source components with minimal degradation of the source's signal. About a decade ago, this principle caused me to develop an interest in passive preamplifiers that by design had minimal impact on the sonic character of the source components. I bought a Placette passive preamp which did an excellent job save for its susceptibility to EMI. The noise of this particular passive preamp led me to buy a Classe CP-800, which seemed about as neutral as any preamp I've ever heard in that it added nothing and subtracted nothing. In recent years, I noted with interest as reviewers observed that better preamplifiers over the last decade not only avoided degrading the source signal, but somehow improved the sonic qualities where tonality, soundstaging, and even resolution were unambiguously improved. Examples of such preamps I read about include Ayre's KX-R and KX-R Twenty, PS Audio's BHK Preamp, and Audio Research's Ref 6. Based on my own experience in recent days, I would describe the Rogue Audio RP-7 as having this quality as well.

There is a running debate about how a preamp improves on a source's signal. How is such an effect possible? Does the preamp add something that wasn't in the recording? Does it somehow unpack the source's signal in a way that an amplifier can't? Are tubes especially good at this? Perhaps not with Ayre and PassLabs preamps as examples.

My Totaldac d1-twelve SE DAC is regarded as one of the best digital sources in the world. Without a preamp, it's sound is musical and extremely well detailed. It has a buffered output which can drive my system without a preamp. But with the RP-7 in place, the soundstage depth is improved and individual instruments and voices have a greater sense of dimensionality/body. Because of this, individual voices and instruments are somehow easier to follow in the midst of complex counterpoint, which symphonic and operatic music have plenty of. As good as my system sounds without a preamp, it sounds even better with the RP-7.

Perhaps engineers will be able to explain just what good preamps do to enhance a hi-fi system’s sound quality. There may already be definitive explanations about this phenomenon already and I’m simply unaware of it. But this topic to me is one of the more fascinating aspects of our hobby that I would love to see explained in engineering (measurement) terms.

Don't forget about Conrad-Johnson's preamps...they have some "street cred", too!

I've participated in a number of experiments with DACs or passive preamps that can drive amps vs. active preamps, and in every case, every person preferred the sound of having an active preamp in the system.

I think the simplest explanation is that they increase signal to noise, and in ways that our brains find that creates an experience that sounds more like what we perceive to be real music.

I'm not sure that the reasons can be entirely explained simply by engineers and/or measurements. The reason I say this is that I don't think we fully understand the nature of perception of hearing, of our brian's deconvolving these auditory signals into what we know as music, and music reproduction etc. Therefore, I don't think we know all the various parameters of what constitutes an engaging and beguiling msuical experience and therefore what to measure, or how to measure them.

An example: how does one measure the way a Stradivarius violin sounds different than a Guanerius playing the same notes or piece of music? They sound different, and we can hear that, but we don't know how to measure to show how they sound differently.

And at the end of the day, I don't think it matters; both are beautiful instruments to listen to.

So, I posit some thoughts for consideration: does it really matter how active preamps do this and what measurements may or may not explain why we prefer them, or should we just settle back with our active preamps, knowing that they make the experience more engaging, and enjoy the music?

Just sayin'!