Contents
Why do gains fall at high frequencies?
The low input impedance offered by the capacitor {C} present in the circuit and also the transistor gain reduces the output at high frequency are the reason off gain falling down at high frequencies. The gain throughout the range remains static and regular, changes occur only at low and high frequency.
How is the high frequency gain of an amplifier limited?
At high frequencies the amplifier gain tends to be reduced to some extent by the presence of small amounts of inductive reactance (which increases with frequency) within the circuit wiring and components, but mainly by stray capacitances. This is the frequency at which the small signal current gain hfe falls to 1.
Is listening to high frequency bad?
High frequency sound causes two types of health effects: on the one hand objective health effects such as hearing loss (in case of protracted exposure) and on the other hand subjective effects which may already occur after a few minutes: headache, tinnitus, fatigue, dizziness and nausea.
How is the frequency of a mid range bump determined?
That simple RC calculation determines the frequency at which high pass filtering is taking place in the Tubescreamer. To determine the frequency of the mid-range bump, one also has to consider the high frequency roll off that is taking place.
Why does gain roll off at higher frequencies?
This gain roll-off is caused by capacitances within the Op Amp circuitry. The reactances of these capacitances decrease at higher frequencies, causing shunt signal current paths, and thus reducing the amount of signal available at the output terminal.
How is the bump frequency of the Tube Screamer calculated?
The bump frequency is calculated using a simple RC calculation of the 4K7 ohm resistor and the 47nF-50nF cap. Somewhere around 720Hz-670Hz. That may seem like a narrow spread, but so much of the human hearing range is focused in the mid range that if it were tuned within the 400-1KHz range, you’ll experience a completely different pedal.
How much does frequency gain decrease with decrease in frequency?
The gain is seen to decrease by 20 dB every 10-fold decrease in frequency (the slope is 20 dB per decade). Hi-fi audio amplifiers, which need to reproduce low frequencies well, should have fl = 20 Hz or lower; otherwise the result is a tinny sound.