Are passive preamps better?

Low input impedance with high output impedance from the pramplifier reduces the output in the base and trebles, they roll off. As a result the mids seem to be pushed forward since the balance of the sound is altered from top to bottom. Typically, as a rule of thumb, the input impedance should be at least 10x the output impedance. With the AI3, I think you would need at least a 20kohm input impedance for balanced sound across the spectrum.

Well I wasn't really saying that age is more of a factor for SS gear than for tube gear. What I was saying is that the the asking price of used gear does not reflect how old an item is. In other words, it's not strictly a case of the cheaper an item is the older it is. Used prices tend to reflect whether an older component has reached 'classic' status vs. just getting old.

Certainly their are 'classic' SS pieces too, like Threshold SA-1 amps, Mark Levinson ML-2 amps, Classe DR-9 amps these units are SS and have reached 'classic' status, thereby holding very good resale value even though they are 20 years old.

Cheers,
John

The old TAP by Bent with its lighting was beautiful and had a remote. I always wanted one. My Tivista CDP w/ its blue feet would have looked great with it!

ET

Lynne:

Pubul57, Why does an amp with a low imput impedence affect the frequency response by increasing the mid's? Why doesn't it simply drive the pre into distortion?

P didn't say that -- he pointed to losses in low freq and very high freq.
Low input impedance means a lot of energy is required from the source component (the component before the amp) to drive the amp correctly. A "passive" pre doesn't provide energy -- it just attenuates it.
So, the task falls on the preceding component -- say, the cdp.

Overall, if the system runs out of steam trying to drive the amp... it's distorting.
(BTW, are you interested in/do you understand, how impedance works?)

If I can speaker to some issues not previously addressed:

There are four functions a line stage has. They are:

1) supply any missing gain
2) provide volume control and input selection
3) provide buffering of the volume control from external impedances
4) (and least understood) control the interconnect cable.

Passive systems provide only #2. Most line stages provide 1-3. If that is all they can do, it will be likely that there will be tradeoffs with a passive, perhaps in the passive's favor. If, OTOH, the preamp is capable of all four functions, then it is likely that the active linestage will be superior.

This is because the interconnect cable plays a serious role in the system. As any passive owner can tell you, the passive sounds better turned up rather than turned down. This is because the passive cannot control the interconnect. At the extreme opposite, a preamp that *does* control the interconnect will be found to be immune to the type of cable and its length.

The unfortunate thing is that you can count the number of such preamps in the high end audio community on your hands with fingers left over, because most preamp designers do not acknowledge the 4th function.

Of course, different line stages exhibit different levels of competence. This definitely muddies the waters somewhat!

This is a good part of why there is a divergence of opinion. There would be none if everyone could hear a competent linestage that can control the interconnect cable, but even that is not likely so this debate will continue.