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Linn Klimax 500 Solo monoblock power amplifier Measurements

Sidebar 3: Measurements

A full set of measurements of the Linn Klimax was made using its balanced input, with selected measurements repeated in unbalanced mode where noted.

Following its 1/3-power, one-hour preconditioning test, the Klimax's chassis was barely warm. The input impedance measured 7.7k ohms (8.2k ohms unbalanced). The output impedance measured a minuscule 0.043 ohms at 1kHz, increasing to 0.071 ohms at 20kHz, both assessed by measuring the voltage rise when an 8 ohm load was open-circuited. Using 4 ohm loads, this increased by a maximum of 0.01 ohm at 20kHz, to 0.…

Linn Klimax 500 Solo monoblock power amplifier Measurements part 2

The small-signal THD+noise vs frequency curves are plotted in fig.3. The results show increasing levels of distortion with lower load impedances—another common result. The distortion from the balanced input is, in all cases, lower than that from the unbalanced connection, but to no pronounced degree.

Fig.3 Linn Klimax 500 Solo, THD+noise (%) vs frequency at (from top to bottom at 2kHz): 4W into 2 ohms, 2W into 4 ohms, 1W into 8 ohms, and 2.83V into simulated loudspeaker load (balanced curves are each slightly lower than unbalanced).

The waveform of the distortion at…

Linn Klimax 500 Solo monoblock power amplifier Measurements part 3

Fig.6 shows the output spectrum resulting from a combined 19+20kHz signal—it shows the intermodulation products resulting from an input signal consisting of an equal combination of these two frequencies—at 273W into 4 ohms. Visible clipping is present above this output with this signal. The resulting IM distortion at 1kHz is under -86dB (0.005%); the highest component, at 18kHz, is -82dB (just under 0.01%). The corresponding measurement at 145W into 8 ohms (not shown) indicates even lower levels of IM distortion.

Fig.6 Linn Klimax 500 Solo, HF intermodulation spectrum, DC-22kHz, 19…

Pace, Rhythm, & Dynamics

Martin Colloms (footnote 1) suggests that the traditional ways of assessing hi-fi component problems overlook the obvious: does the component dilute the recording's musical meaning?

For all its quantifiable technical faults, easily identified in the laboratory when compared with the measured near-perfection of CD, the vinyl LP disc possesses a powerful and effortlessly musical content, with an easy, fundamental rhythmic stability and solidity. Interestingly, this innate character seems to be quite robust, more so than digital. Subjectively rewarding results may be obtained from analog…

Pace, Rhythm, & Dynamics Page 2

Definitions
The definitions of "pace," "rhythm," and "dynamics" inevitably involve such related aspects as drive, timing, involvement, flow, and coherence. "Pace," for example, connotes speed; indeed, the concepts "fast" or "slow" have often been applied to sound reproduction.

Pace: At the simplest level, pace is equivalent to tempo. While a listener may well have a good awareness of absolute tempo, there is a strong subjective element in the perception of the speed at which a musical work is performed. This is determined in part by what has come before. The same is true of the…

Pace, Rhythm, & Dynamics Page 3

Dynamic dilution: Realism in reproduced dynamics goes even further than this. Comparisons with live sound repeatedly show that the recorded or even just the amplified form suffers a significant loss of dynamic quality when it comes to reproducing music's inner dynamics. While an engineer might instinctively accept the notion that an audio transmission system has a finite dynamic window and that audible limitations may well be audible when waveform peaks reach the limits of that window, the idea that sounds nicely placed in the middle of the working range could still suffer in terms of…

Pace, Rhythm, & Dynamics Page 4

The designers who cared about rhythm felt---and may still feel---that they possessed some basis for a common understanding of the lifelike reproduction of recorded music. That understanding was not intentionally distanced from the main high-end thrust. However, whenever dialogue was initiated between the two camps, it transpired that they were often not on the same wavelength. Pieces of equipment from the two design schools even sounded uncomfortable when used with each other. At times insults were traded between the various proponents, while both took comfort from their allegiances to…

Pace, Rhythm, & Dynamics Page 5

It is an unfortunate fact that hysteresis problems are not restricted to the large-amplitude movements found in bass drivers. They can also affect subjective timing in the mid- and treble ranges, though not to the same degree. Analysis of many speaker reports suggests that tweeters with foam or fabric suspensions time better than those using vinyl or similar materials.

In addition, the potentially anomalous mechanical behavior of ferrofluid has to be balanced against its benefit in terms of reduced voice-coil heating. The ferocity of such vibrations---small in amplitude but very fast---in…

Pace, Rhythm, & Dynamics Page 6

Amplifiers & dynamics
It's hard to extrapolate from mechanical and acoustic concepts, whose effects may be directly appreciated in physical terms expressed in the movement of sound-reproducing structures, to electronics. In an amplifier, the sound pressure is represented by its electrical voltage analog due to currents flowing in wires and electronic components. Yet there is now the beginnings of a dossier containing data on electronic parallels with the acoustic rhythm experience. There are related types of uncertainty or randomness in electrical behavior which can disturb the…

Pace, Rhythm, & Dynamics Page 7

Such design practice goes far beyond simple engineering considerations. Where high-quality audio is concerned, the dollars/watt ratio is no longer the prime consideration.

Other established design factors also make sense. For example, operating an output stage in class-A largely stabilizes its operating characteristics. One may also include full regulation of the power supply, which removes the uncertainties and randomnesses of power-supply behavior. Deleting various low-frequency time constants in the circuit also appears to be helpful, hence the trend to DC coupling, with servo circuits…