6. Pre-amplification

6. Pre-amplification


Author: Karsten Hein

Category: High Fidelity

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A pre-amplifier can well be considered the heart of our system. Since many pre-amps will feature a built-in phono stage, for MM, MC, or both, there is some amplification involved, however, the term describes more its position before the amplifier than its calling. Pre-amps generally serve as a hub to rout music signals from multiple sources to a single power amplifier. All preamps add a sonic signature, and, because of their central position, this signature will make or break a good system.

It therefore makes sense to choose our preamp well, and there are some pointers to look out for: 1. Signal integrity may be corrupted when running though potentiometers, hence, audiophile units will rarely feature bass, treble, and other attenuators. 2. Power supplies may inject interference into the signal. Many units therefore place the power supply in a separate housing. 3. Thin conductor tracks on the circuit board may cost speed and dynamics. 4. 2D circuit board layouts may pick up interference. High End units will often have a greater degree of direct wiring.

For my own system I chose a pre-amp from a lesser-known US manufacturer who have been constructing their DB Systems DB1 with the power supply DB2 from the 1970s until today with only minor changes. The unit is built under consideration of the four pointers mentioned above and produces a remarkably natural and inviting midrange with overall extremely low distortion. It can feed two amplifiers, a very convenient feature that I have at times made use of, e.g. for bi-amping hybrid speakers.