Building an amplifier taking into account the directions of electrical components

Construction of an amplifier taking into account the directions of electrical components based on Telefunken components and wires manufactured in 1930-40

Introduction:

Changes in sound when changing the direction of the interconnect cable have been noticed for a long time. Back in the seventies, arrows began to be drawn on expensive cables, rigidly defining the input and output of the cable, and manufacturers argued that subjectively, the sound quality when the cable was turned on in the direction of the arrow was better (despite the fact that, from a scientific point of view, this is complete nonsense).

Be that as it may, the higher the class of the sound reproducing path, the better the difference in sound is heard when changing the direction of the cable, and the more preferable is the direction “in the direction of the arrow”. Numerous attempts to explain this difference at the level of physics have not been crowned with success, measuring instruments also do not register any changes in the electrical signal, while at the level of subjective impressions these phenomena are confidently confirmed.

Let me remind readers that our hearing, like a voltmeter and an oscilloscope, is a measuring instrument. This means that if certain methodological conditions are observed, measurements by ear (subjective measurements) are considered significant. Subjective measurements are widespread in psychophysics and in audio expertise.

In contrast to the so-called objective measurements, subjective measurements contain a statistical error, therefore, it is necessary to assess the reliability of the results obtained. Subjective measurements can be considered reliable if one expert or several experts in a blind test repeat subjective assessments, say, in 80-90 cases out of 100 measurements. The credibility depends on the ears of the experts, the musicality of the material used, the clarity of the evaluation criteria and the resolution of the path.

The study of the directivity properties of wires and elements in the signal part of the sound-reproducing tract began in the same seventies. The known results are quite contradictory: on the one hand, it was found that the directions of the wires in the section of the circuit between the DAC and the grid of the input lamp are closed along the circuit.

Moreover, the cold (ground) wire is directed to the DAC “from effect to cause”, and the hot (signal) wire to the grid of the input lamp “from cause to effect.” The same rule was established in the section “cartridge – RIAA input tube grid of the equalizer”. On the other hand, there is an opinion that both signal and ground wires must be oriented “from cause to effect.” At the same time, few of the researchers took into account that the correct direction of the wires and all other elements of the electrical path is equally important in signal circuits and in DC and AC power supply circuits. This article provides guidelines on how to orient the wires and components in all circuits of the sound reproducing path.

Terms and Definitions:

The character of the sound of the wires connected in the forward and reverse directions is distinguished by its color and clarity. There are other more subtle differences (at the 2nd and 3rd levels of perception), but we will not touch on them here.

Coloring is “… the underlining (or darkening) of certain frequency regions of the audio range, marked by our perception.”

Moreover, this emphasis can be both subjectively beautiful and harmonious, and vice versa.

Each component of the tract has its own individual, inherent only to him, color. The general color of the tract is a kind of “chorus” consisting of individual colors of each component and each piece of wire. In a path with good resolution, the voice of each component is heard to a greater or lesser extent. Therefore, to achieve the natural sounding of the path, components and wires are selected only with a natural, harmonious, mutually complementary color. This is how harmonization is achieved [8] sounding tract.

Clarity is a key indicator of the sound quality of audio equipment. Clarity is responsible for the intelligibility and detail of the sound, determines the ability of the tract to transmit intonation, the character of the performer’s sound production. The loss of clarity increases with the addition of each new component, wire, or connection in the path.

Correct wire direction is the direction that provides the best clarity. Subjectively, the increase in clarity is accompanied by highlighting and concentration of the HF, the “tension” in the midrange and midbass decreases, the sound as a whole becomes more natural.

In complex transistor circuits, HF concentration is the only reference point. The sound begins to “come to life” only when it reaches a certain threshold, which is quite difficult to achieve with transistor technology with multi-way speaker systems. Upon reaching this threshold, the correct direction can be determined even by telephone, which is confirmed by the experiments of Anatoly Likhnitsky

The sound in the wrong direction of the wire can be more tonally balanced and therefore in paths with low resolution (lack of clarity), the expert may prefer the wrong direction. However, such inclusion is not recommended if a truly high-quality amplifier is to be built, since the loss of clarity is not compensated for, while tonal imbalance is eliminated by harmonizing the elements in the right direction.

Experimental tract

The experiment to determine the correct directions of wires and components was carried out on a single-ended amplifier (Fig. 1) The choice of the type of amplifier and its circuitry features correspond as much as possible to the principle of “shortest signal path”. The shortest signal path guarantees the highest possible resolution of the sound reproducing path at the initial stage of work.

Method for determining the direction of wires and elements

Stage A – determination of the correct direction of the conductors and their labeling. In the experimental amplifier, two copper petals isolated from the body were brought out to the front panel at a distance of 10 mm from each other. One petal is connected to the additional input RCA connector (not indicated in the diagram) and the other to the con2 connector (Fig. 1).

One end of the tested piece of wire is stripped to a distance of more than 10 mm and simply leaned against the petals with a stripped spot, first in one direction and then in the other. After determining the correct direction, the beginning of the wire section is marked with paint.

Stage B – determination of the direction of inclusion of the tested conductors in different parts of the amplifier circuit. Each connection in the installation of the amplifier in turn, starting with the signal circuits, was replaced by pieces of wire marked in step A. In each connection, the marked piece of wire was listened to in both directions and the position of the conductor was chosen at which a higher clarity of sound was noted.

Upon completion, the direction arrows were plotted on the diagram in Fig. 1 according to …