Passive Pre-amp: Improves overall sound quality??


Sam Tellig in Stereophile was all jazzed up about a line of "passive pre-amps" he received for review How does a passive pre-amp work?? Is it powered by wall AC?? What are some of the pros and cons of its operation within an audio system??
sunnyjim
When it comes to active preamps Ralph is the only designer I know that adds one more item to the list of what an active preamp should do and that is control the interconnect. As someone who is very passive friendly I can respect this point of view. If an active preamp is "acting" as a tone control then it is a flawed design or designed to perform that way, which in my opinion is wrong headed thinking, or it cannot control the interconnect and its artifacts. Transparency should be the key attribute of any preamp.

BTW I currently use a passive with my analog set up (tape and vinyl) with no issues. That is soon to change though.
While I'll agree with Sam's article about passive pre's I did have a chance to listen to that particular passive unit for several weeks and it was extremely good but I still preferred Steve McCormack's VRE-1b pre-amp and by a wide margin, which by the way only puts out 6dB of gain. There's an axcellent review that just came out here:
http://www.ultraaudio.com/index.php/equipment-menu/284-smc-audio-vre-1c-reference-preamplifier

(Dealer disclaimer)
Marebg, you forgot one of the most important things a great active is needed for.

- great sounding music from a stereo system

At least this has been my experience even when all the stars were aligned perfectly for a passive to shine.
Do you suppose that Sunnyjim is really a troll, recognizing that we haven't all gotten our fists bloodied over the passive vs active debate for at least a month?
Lets list what a preamp does:

1. source selection
2. voltage gain
3. attenuation
4. buffering (impedance matching)
5. tone control (older preamps,typically)

Let's get rid of #5 for now- passives don't have them, most good line stages don't either.

To that list we can add 'control (and limit) the effects of the interconnect. So:

1. source selection
2. voltage gain
3. attenuation
4. buffering (impedance matching)
5. control the effect of the interconnect cable.

The the latter 2 aspects are not served by any passive or transformer device. If you have ever heard the difference a cable can make, then you might appreciate that if the preamp is doing its job, the difference between a $100 cable and a $10,000 cable could be rendered inaudible. Now some people want to pay for the cable so that they can say that they did that, but if you are not one of those people you might consider that you can get the same or better performance without that $10,000 cable if your line stage is built with that ability in mind.

I find the colouration of uncontrolled cables to be unacceptable in any system. Sure it sounds transparent, but where is the body and impact? Not making it to the amplifier is the answer. To get around this problem people with passives will spend of lot of time and money sorting out the cable issues as best they can. So if you are thinking passive or TVC, keep in mind that the interconnect is the hidden and mandatory cost.