Moderatoren: Moderatorenteam, Thargor
Viele analoge Grüße !... The design exploits Graham Slee's "Phase Integrity" investigations, using high speed amplifiers inside fast equalisation networks, and incorporates "Q-busting" inputs. All of which allows more music to reach the outputs, and less of the annoying vinyl noise and distortions. ...
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Och Mensch, spring über deinen Schatten. Traue Dich.Sauron hat geschrieben:
Ich sag mal lieber nicht, mit welchem wesentlich teureren Vorverstärker er zumindest gleichgezogen hat. Ich kriege sonst Haue (mal wieder
... What is meant by inferior? Is the writer saying the op-amp [a group of transistor junctions etched onto a single piece of silicon] is inferior to a group of discrete bipolar transistor stages [a group of transistor junctions etched onto separate pieces of silicon]?
If so, you ought to consider the Ebers-Moll equation [the mathematical model of the transistor]. Amplification happens because of the relationship between collector current [output] and base-emitter voltage [input] by
IC = IS [exp (VBE/VT) – 1]
Where VT = kT/q = 25.3 mV at room temperature [68°F, 20°C], q is the electron charge [1.60 x 10-19 coulombs], k is Boltzmann’s constant [1.38 x 10-23 joules/°K], T is the absolute temperature in degrees Kelvin [°K = °C + 273.16], and IS is the saturation current of the particular transistor [depends on T].
Don’t worry if you are not mathematically inclined. Just count up the number of temperature related terms in the above equation. You will notice that transistor performance is temperature dependent.
A number of discrete transistors dotted around a circuit board will each differ in temperature because they are separate to each other. 1] By necessity some transistors operate at different currents to others and self heat to different temperatures; 2] Some will dissipate heat better than others because of differing widths and lengths of PCB traces they are soldered to; 3] Some transistors may be closer to heating/cooling influences elsewhere in the equipment than others.
The temperature profile of an op-amp is considerably superior as the op-amp case encapsulates all the transistors which are etched onto a single piece of silicon. From switch-on all the transistors will eventually reach the same operating temperature, and thereafter any temperature drift [dT] will be common to each transistor, and hence the performance will always be at an optimum.
It is therefore obvious that the temperature profile of a discrete transistor grouping [and thus its performance] is less predictable than an op-amp. ...
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