The preamplifier can be considered the center of the ultimate Hifi or High End audio installation.
Current preamplifier range at Ohm-Audio BV
The role of the preamplifier is often underestimated.
Why use a preamplifier if you can also control the volume digitally? What can an extra device in the signal path really improve?
It can't possibly sound better, can it?
..?
On the one hand, it seems so logical. Suppose you have a beautiful Bricasti M1SE DAC, a CD player with adjustable output, and the built-in buffer can deliver up to 2Volt, 4Volt or 6Volt. Why would you then need an external preamplifier? Extra electronics, an extra signal cable, an extra power cord....that can't possibly make it sound better? Moreover, sometimes there are considerable costs involved. It sounds logical, yet...and yet.....
From experience we know that a good Hifi or High End installation sounds better with a good preamplifier. That latter part is logical. A poor, mediocre or at best adequate preamplifier certainly does not bring improvement. At most it brings change, and that is not always positive.
How is it that your High End system sounds better with an extra device in the signal path?
The first requirement is therefore that the preamplifier is of very good quality. That it adds very little of itself. Some additions are unavoidable but these can be at such a low level that the negative properties of the extra preamplifier are negligible. The sound does not get worse from it. But how can it then get better?
Many people disagree on this. We stick to the following.
The buffer stage of the DAC or CD player no longer has to deal with the input stage of the power amplifier, but with that of the preamplifier. The input stage of the preamplifier is a very simple load for this output stage of the DAC or CD player. That output stage has it easier, than when it has to drive the power amplifier directly. That is because the power amplifier drives the speakers. Current also comes back from the speakers to the power amplifiers, because the units vibrate and thus generate current themselves. Part of this return current leaks back to the input of the power amplifier, and thus places high demands on the output buffer of the preamplifier, or the DA Converter with adjustable output. The separate preamplifier has the advantage here and also protects the connected source. Advantage 1.
The separate preamplifier takes control of the incoming signal from the source, attenuates it, and regulates the output voltage (Volume) and possibly balance, and sends it to its own output stage. A very good preamplifier has a very good output stage which is of higher quality than that of a DA Converter with adjustable output. The output amplifier of a preamplifier can often deliver 20 Volts without any problem. So the output stage that now drives the power amplifier is of better and heavier quality than the output amplifier of a CD player or DAC. Advantage 2.
The separate preamplifier has its own chassis, power supply and control circuit. It is therefore not an output amplifier powered by the same power supply as the DA Converter or CD player. This provides more stability and higher sound quality. Advantage 3.
Controlling the output level (Volume) is a very delicate matter. A simple potentiometer in the signal path does not do much good, but a digital volume control does not do much better either. However you look at it, if you control the volume digitally (i.e. attenuate) then the signal becomes rougher. Bits are lost. The resolution of the music signal decreases. And that is audible. A good external preamplifier has state of the art analog volume control, and that is audible. Advantage 4.
An external preamplifier has extra possibilities. Extra analog inputs, sometimes a Phono preamplifier, dual output stages and so on. More versatile therefore. Advantage 5.
In short, a good Hifi or High End installation improves sonically and becomes more versatile through the use of a good preamplifier. Incidentally, you don't have to take our word for it. Best of all, you can try it out for yourself.
Ohm-Audio bv 2018-10
