:) you missed one, in a way the granddaddy of them all.
The Atma-Sphere MP-1 was/is the world's first balanced line preamp, having been introduced in 1989. It is unusual in that it is also all-tube, but has a direct-coupled output, something unusual in any tube preamp. This allows it to be more transparent.
Balanced line operation has certain advantages. If you really want to experience them, whatever preamp you get should have these two characteristics:
1) the output should appear between pins 2 and 3 of the XLR connection, ground being ignored and only used for shielding. This helps reduce the effect of the interconnect cable.
2) the preamp should be comfortable driving low impedance loads. If not, its output impedance can interact with the cable, allowing the cable to color the sound. IOW again we want this to insure cable control and immunity. By 'low impedance loads' I mean 5Kohms or less.
If lacking these characteristics, the preamp will not be able to take advantage of everything the balanced line system has to offer.
For example, the balanced system was created to eliminate cable colorations. Audiophiles have long thrown money at that problem, hoping for a cure, but it was actually solved back in the early 1950s or so (the balanced line system). This allows for long cable lengths (although it still an advantage even if the cable is only 6") and the assurance that as long as the cable is properly built, it will not add or detract from the sound.
This BTW is why audio engineers often scoff at audiophiles that spend several house payments on cables. They know that cables don't make a difference! But they live in a world of balanced lines....
Want proof that this is so? Look to Mercury records or RCA Living Stereo LPs. Quite often the microphone cables were over 100 feet to get to the input of the tape recorder, but the recording is pristine. It is because this problem was solved by balanced lines.
The Atma-Sphere MP-1 was/is the world's first balanced line preamp, having been introduced in 1989. It is unusual in that it is also all-tube, but has a direct-coupled output, something unusual in any tube preamp. This allows it to be more transparent.
Balanced line operation has certain advantages. If you really want to experience them, whatever preamp you get should have these two characteristics:
1) the output should appear between pins 2 and 3 of the XLR connection, ground being ignored and only used for shielding. This helps reduce the effect of the interconnect cable.
2) the preamp should be comfortable driving low impedance loads. If not, its output impedance can interact with the cable, allowing the cable to color the sound. IOW again we want this to insure cable control and immunity. By 'low impedance loads' I mean 5Kohms or less.
If lacking these characteristics, the preamp will not be able to take advantage of everything the balanced line system has to offer.
For example, the balanced system was created to eliminate cable colorations. Audiophiles have long thrown money at that problem, hoping for a cure, but it was actually solved back in the early 1950s or so (the balanced line system). This allows for long cable lengths (although it still an advantage even if the cable is only 6") and the assurance that as long as the cable is properly built, it will not add or detract from the sound.
This BTW is why audio engineers often scoff at audiophiles that spend several house payments on cables. They know that cables don't make a difference! But they live in a world of balanced lines....
Want proof that this is so? Look to Mercury records or RCA Living Stereo LPs. Quite often the microphone cables were over 100 feet to get to the input of the tape recorder, but the recording is pristine. It is because this problem was solved by balanced lines.