Poll - Active vs. Passive preamp

I'm using an active tube preamp (Audioprism Mantissa), before the Mantissa, I used a passive TVC (Bent Audio).

Different systems, same results....I'm happy.

Dave

Thanks for the responses.

I should've been more specific and said "TVC" as that's what I really meant. To me, at least, resistor passives are ALWAYS unacceptable - dynamics, gone!

Of course for the TVC (or any passive) impedance matching is the key. I take that as a given - if you don't have an amp Zin/source Zout ratio of at least 50:1, and preferably better, don't even bother with a TVC. At least, don't expect it to be able to compete with state of the art tube preamps.

I current have at least 100:1 with my digital source, but don't know the Zout specifically of the graham slee phono stage - they don't publish it. But I'm sure it's low, probably way under 1K.

I am firmly on the fence on this one. I am a former TVC owner and have sung it's praises here. And in the right system (especially with the right amp) it is indeed hard to beat. But after upgrading to a CJ Premier 140 I realized that it was not "passive friendly". It is indeed a better amp than my previous RM9, but really needs an active gain stage before it to realize it's potential. Not trying to be too ambiguous here, but I think a TVC or a REALLY good active linestage can be equals, but usually not in the same system. One or the other will sound better in any given situation. Don't ask me about resistor based passives, because they don't even merit discussion.

Oz

Paul, doesn't your supratek use a passive resistor volume control? When you turn that knob to control the volume isn't that a variable resistor? Why is that killer and what you call a passive is not?

Amfibius, your problem with dynamics had nothing to do with the fact that the preamp was passive. If the volume is all the way up and it isn't loud enough you didn't have enough overall gain for your combination of source-speakers-room. Adding an active preamp with gain solved that problem.

Here is the bottom line. Most don't understand that ALL volume controls are passive. They may be in a box with active gain stages so we call it an active preamp, but the thing that controls the volume (resistor voltage divider, TVC) is ALWAYS passive. Designing it as a unit and using an active stage to buffer the input and/or output of the control removes variables for the uninformed audiophile and they often get better results with an active stage. Not because active is superior but because they didn’t properly implement the passive control. Most actives are plug_and_play because the standard is high input and low output impedance. This is easy to achieve with active buffer circuits in the preamp but adding an active stage must also degrade the performance in other ways. Passives can’t always follow these rules so what comes before and after is critical to their performance.

As stated above careful attention must be paid to impedances and cabling to maximize the performance of the passive. This is exactly what the designer of an active stage does for you, but if you are knowledgeable about what is going on and you don’t need the extra gain going passive is always superior.

Herman,

That's certainly one view. But an active is providing impedance matching and buffering while a "passive" is not. Of course the VC itself is "passive"; I have a rather difficult time imagining anything else, don't you?

The "excess gain" argument has been stated ad naseaum. These days, nobody needs the gain of an active linestage - almost nobody certainly - yet they sound better in some systems, even when there would be plenty of gain without another gain stage.