My opinion, for what it is worth.
Active pre amps have generally given me a livelier sound. I use Meadowlark speakers which are on the laid back side so this is a bit of a benny for me. However, they have all done this at the expense of increased noise and too much gain.
As far as resistive units go, I have not cared for the switched discrete attenuators I have tried so far (just had a DACT in my system finally and I was unimpressed). I prefer the sound of carbon pots over plastic as well. So far the best solution I have tried is a fake law carbon pot. This is a linear pot with a specifically calculated resistor tied between the wiper and ground. I use a 100K pot with a 15K resistor. Linear pots are better constructed and have much better channel balance than audio taper (log) pots, plus the addition of the matched resistors forces even better balance. I have heard tell that cermet pots are even better in this regard, but I have not tried one (it's on my to-do list).
Transformers may work well, but they are inherently non-linear devices so I would not scrimp here. Buy only the best and most well regarded to be safe. That said, they could have some unique benefits over resistive attenuation, such as ground loop noise cancellation and inherent band pass filtering. This means using a TVC might give you a quieter, more powerful amp right off the bat. This may indeed be a factor in the high regard these units receive. Honestly, I think it is worth a look, but the price of admission is too high for me right now
Personally, I think the ultimate solution is a power amp with a high input impedance (a meg or so) and an input sensitivity approaching 2 volts (maybe even over 2 volts if the amp is higher powered and/or the speakers are efficient). This would allow most sources to hit a 100K + volume control and still drive the amp well with almost no noise.
Rob
