Do I really need a preamp?

Even with a DAC capable of 10V output, in my system a preamp provides more bass power, dynamics, and detail. Up until a month ago, I've found that passives may be cleaner than actives, but to varying degrees lean the sound and lose some of the power of deep bass.

That was until I tried the Tortuga LDRxB preamp. It uses light dependent resistors (LDRs) to both switch between inputs and to provide attenuation. It has all the deep bass, power, dynamics, as well as delicacy in the mid/treble of the best active preamps I've heard. It also has a self-calibration feature that the user can run to maintain long term impedance tracking channel.

A Constellation active preamp that uses LDRs for input switching and volume control sells for $65K. The Tortugas are $1500 or $2400 for the SE or balanced versions.

I use a passive and have for about 25 yrs. I have never really wondered much why it sounds good to me. I have had and listened to new and older ss and tube pres in the 2000-8000 range. And I always go back to a passive. I have heard systems with passives sound really bad, much like has been described by others. I just had a thought and maybe this has been considered before. I know the passive does not introduce much of a coloration but because of its lack of a gain stage it may lack some control over the signal which could and probably does effect the sound. But I think more than that the passive seems to revel what else is in your system. Before and after it. And when a passive is introduced and the sound leans out or is to clean or other negative traits it maybe that the equipment it is put in the system with may not be up to working well together. If you could begin by getting the amp and/or speakers and/or cables or whatever that plays well with a passive or in other words with a component that logically couldn't do much harm to a signal but rather complement its sound you could really enjoy a passive in that system. And then that begs the question- Because a passive really doesn't do much to a signal is a lot of the equipment that is in our systems not very good sounding on its own? Not to be controversial, but I do wonder.

Marqmike, I have always seen it as a statement of how bad many active line stages must be for a passive to beat them. I can't use a passive in my system- the result would sound broken- no bass, no impact. The active preamp I use has more detail as well.

So much depends on setup! My interconnect cables are fairly long, something that is not a good idea with a passive. I find though that by keeping the amps by the speakers and the speaker cables short that I get a lot more resolution. The front end equipment- preamp, tt and digital, reside on an equipment stand that is located in a room nadir where there is the least bass. It is also not too far from my listening chair.

Its all about synergy as usual I think. Passives make sense to me if properly mated to suitable sources electronically. That might even be one of the best ways to go if done right, at least from the "purist" point of view, a simple signal path that mates well to gear upstream.

What's not to like?

Mating of active pre-amps, especially tube gear, opens up a similar but different can of electronic mating issues to address. Plus the preamp itself becomes more of a potential sound tweak.

There are so many ways to tweak and do it right. Active/passive, who cares really? Just choose your paradigm and do it right! Passive pre-amps offer a different way to do things. Options are good. Just get it right.

The problem you are usually facing with passive controls is the interconnect cable. An active line stage will usually be less sensitive to the cable. In fact if done right, the active line section will control the cable so well that it will have no sonic effect at all.

Passives OTOH require that one be very careful about the cable. Some passives are lower values, such as 10K, which make them less cable sensitive but then you have the problem that not all sources can drive the 10K properly.

I have presented some of the math about why passives can put you at a disadvantage elsewhere on this site, and the math shows that the quality of the control has nothing to do with it.

This is not to say you can't get a passive to work quite well, just that you do have to be careful and results vary quite a lot. Generally speaking though, it means short cable runs.

'Just get it right' is indeed excellent advice.