Why go with active preamp?

I've got an Adcom GFP-750 so it's easy to compare passive vs. active. With a good CDP with output buffer, I don't see much difference in dynamics. I think the CDP output power supplies may also affect dynamics but maybe someone with more experience would know better?
With a cheaper CDP which did not have the output buffer, there was a fairly noticeable loss in life to the music. Even though it has 2 volt output.
But I think a goldpt or DACT passive attenuator may give better transparency than the Adcom. The Adcom seems to lack ultimate transparency. At least that's what people here have said going from Adcom GFP-750 to a Pass Aleph preamp. The other option I have is to upgrade the volume or capacitors on the Adcom.
I don't see how anything could be more transparent than a DACT attenuator. But if there is an impedance problem, maybe an active pre is necessary. I've read some passive pre's have a resistor network to correct for these potential problems.
Some passive pre's are very expensive. Look at Placette ($1,500) or FT Audio's Little Wonder ($600). That sounds like a lot of money for a volume knob in a box. Does anyone have experience with either of these?

So the main question I have is: other than dynamics, is the purpose of an active preamp to be a tone control to further tweak the sound of the system?

Sean nailed it. I have played around with many passives (transformer-coupled and regular resistive, etc.), and none of them did EVERYTHING right as opposed to the active linestages I have used. Even with most actives, something has to give, but the best I have heard are the Audion preamps from the UK- basically a buffered line stage, point-to-point silver wired simple circuit using 3 6922's for the phono stage and one for the line stage. The Premier Quattro 4-box version (dual outboard power supplies) is da bomb...

The question is not that straight forward and everyone should in this case integrate components.

Is there any CD-player or phono-pre that is able to throw 8...12Volts on the output out here? I know that not too many and if you need that kind of output to feed your amp than you wouldn't get away without active preamp.

Many poweramps are in reality sort-of integrated ones with high input sencitivity and gain that is very close to integrated amp except the volume control: McCormack, Counterpoint, VTL, Bryston... SS amps even have an extra input high impedance small signal stage making three all together: input stage, driving stage and the output stage where the input stage in reality is a preamp! Do you need to go active in that case? I'd say no... If you already have preamp why get another one on your signal path? In case with tubes an input tube with its local feedback signal return as a buffer tube as well so you don't even need your CD-player or DAC to be buffered.

Another aspect is that poweramp sencitivity is usually rated Volts/per FULL output power and the sencitive ones go from .6V upto 2V depending on delivered output power. Do you always listen on the peak powers? Than I'd say it's wrong. The best volume position is where the amp "feels" the best.

I've done measuring and plotting graphs experimentations of many amplification devices FETs, Bi-polar and vacum tubes and figured that excessive attenuation before input drastically changes the bandwidth curve of ANY amplification element. The amplification ratio 'dB v.s. bandwidth depends on the working region of the input/output characteristics. Mainly the IMPEDANCE characteristics of the any active element will dictate the shape of curve for any imput signal.
The best and simple example to demonstrate for casual listener is to bring to your system TWO active preamps connected in series(I know that that is to extremes but very and very obvious). Use the first preamp for the volume and on the second one set the volume to the minimum. In result you will only hear bass and upper freequencies with midrange laid far far back. The same situation but to the less degree occurs when high gain active preamp is used with high sencitivity amp.

There are simply a couple of philosophies in audio electronic devices and different manufacturers take either one of them or combine both and thus every component does perform its own task for what they've been designed.

Shortly saying one would say that preamp should be designed for the minimal task and the other would say that poweramp is a critical component... The rest is for your ears and experimentation.

P.S. you can easily search through the older posts here to find out about successfull integration of a passive preamps into your system.

I did not have good results in my system going cd player direct, music was lifeless. Even the famed audio aero sounded lifeless too me going direct. But it is you who has to be satisfied with the results not anyone else. The music is much more satisfying too me utilizing an active pre-amp. So as others have suggested you need to experiment to determine what works best for you. Happy listening

Chuck

I went down this road already for a while. I think there are probably ways to make passive preamps (or no preamp) work, but you really have to be willing to tweak your system and try lots of combinations out, and you have to have quality source and amp components that deal well with no pre. That being said, I could never make it work in my system, and the sound from my new active (Plinius 8200 mkII) is pure heaven compared to my experience with a passive setup.

Sometimes something seems like it should work but just doesn't.