0dB gain question

...so theoretically saying that passive preamps are more volume position depended than active ones and best performed onlyat high volume levels?

No, the passive unit is strictly dependant on the output level of your source unit(CD player,etc) If you have a high enough output from the line level source, passive is fine at any volume level that doesn't exceed your amplifier's input sensitivity specification. If you have a very low output level from the source, then you will need an active preamp to amplify the source to a level suitable for your amplification unit. As mentioned above, the impedance may or may not be an issue, depending on the system.

One fine point on gain and attenuation. To attenuate means to reduce. Gain, on the other hand, does not mean to increase. It can be either positive or negative or zero. A gain of +dB means to increase, a gain of -dB means to reduce, and a gain of 0dB means no change.

A typical specification given for a preamp is the maximum amount of voltage gain it has. For a passive preamp this is usually 0 dB. In other words, when turned all the way up, the output voltage is equal to the input. However, a passive preamp with a transformer can have a voltage gain. This is unusual though.

Wow! is there any passive preamp with output trany there?
Or maybe someone DIY-designed one already. I definitely want to try it!