1.
In a push-pull amplifier, what makes an input signal two of equal amplitude and opposite polarity?
Correct Answer
C. pHase Splitter
Explanation
A phase splitter is used in a push-pull amplifier to generate two signals of equal amplitude but opposite polarity. This is achieved by splitting the input signal into two separate signals that are 180 degrees out of phase with each other. The phase splitter circuit typically uses components such as transformers or transistors to achieve this phase shifting effect. By having two signals with opposite polarities, the push-pull amplifier can effectively amplify the input signal while canceling out any even-order harmonic distortions, resulting in a cleaner and more accurate output signal.
2.
Which of these is not an actual twentieth-century amplifier brand?
Correct Answer
B. Real Time
Explanation
Real Time is not an actual twentieth-century amplifier brand. Marshall, Peavey, and Fender are all well-known and established amplifier brands that have been around for many years. However, Real Time is not a recognized brand in the amplifier industry during the twentieth century.
3.
For vacuum tubes used in power amplifiers, the filament power supply is typically how many volts?
Correct Answer
B. 6.3 Volts Ac Or Dc
Explanation
The filament power supply for vacuum tubes used in power amplifiers is typically 6.3 volts AC or DC. The filament, also known as the heater, is responsible for heating the cathode of the vacuum tube to emit electrons. This voltage is necessary to ensure proper operation and longevity of the vacuum tube. The option of 6.3 volts AC or DC indicates that the filament power supply can accept either alternating current or direct current as input.
4.
Which one of the following is not a common amplifier distortion?
Correct Answer
C. Apochromatic Distortion
Explanation
Apochromatic distortion is not a common amplifier distortion. Slew Rate Limiting refers to the maximum rate at which an amplifier can change its output voltage. Intermodulation Distortion occurs when two or more signals mix together and create additional frequencies. Total Harmonic Distortion refers to the distortion caused by harmonics of the input signal. However, Apochromatic Distortion is not a recognized type of distortion in amplifiers.
5.
A vacuum tube predominately amplifies which of the following?
Correct Answer
A. Voltage
Explanation
A vacuum tube predominantly amplifies voltage because it is designed to increase the strength of an electrical signal. Voltage represents the potential difference between two points in an electrical circuit, and amplifying it allows for a stronger signal to be transmitted. By contrast, resistance refers to the opposition to the flow of electrical current, and current is the flow of electric charge in a circuit. Vacuum, in this context, is not directly related to the amplification process in a vacuum tube.
6.
What famous amplifier was published in the magazine Wireless World in 1947, and set a standard of performance that was years ahead of its time?
Correct Answer
C. The Williamson
Explanation
The Williamson amplifier, published in the magazine Wireless World in 1947, was a famous amplifier that set a standard of performance that was ahead of its time.
7.
A tetrad vacuum tube utilizes how many grids?
Correct Answer
D. 2
Explanation
A tetrad vacuum tube utilizes two grids. Grids are used in vacuum tubes to control the flow of electrons. In a tetrad vacuum tube, there are typically two control grids, one screen grid, and one suppressor grid. The control grids regulate the flow of electrons, while the screen grid helps to increase the efficiency of the tube. The suppressor grid helps to prevent unwanted secondary emission. Therefore, the correct answer is 2.
8.
How many grids does a pentode vacuum tube have?
Correct Answer
A. 3
Explanation
A pentode vacuum tube has three grids. The grids are used to control the flow of electrons within the tube. The first grid, called the control grid, determines the electron flow by applying a varying voltage. The second grid, called the screen grid, helps to accelerate the electrons towards the plate. The third grid, called the suppressor grid, is used to prevent secondary emission of electrons. The presence of these three grids allows the pentode vacuum tube to have better control over the electron flow compared to tubes with fewer grids.
9.
In Great Britain, what is the vacuum tube known as?
Correct Answer
A. Valve
Explanation
In Great Britain, the vacuum tube is known as a "valve." This term is commonly used to refer to the device that controls the flow of electric current in electronic circuits. The term "valve" is derived from the fact that the device operates by controlling the flow of electrons through a vacuum, similar to how a valve controls the flow of fluids through a pipe. This term is widely used in British English to describe vacuum tubes, while in other regions, such as the United States, the term "vacuum tube" is more commonly used.
10.
A Futterman amplifier is unique due to what fact?
Correct Answer
A. It Does Not Use An Audio Output Transformer
Explanation
A Futterman amplifier is unique because it does not use an audio output transformer. Unlike other amplifiers that rely on a transformer to transfer power from the output stage to the speakers, a Futterman amplifier uses a different design that eliminates the need for this component. This allows for a more efficient and direct transfer of audio signals, resulting in improved sound quality and performance.
11.
Which statement best describes Class A amplifier operation?
Correct Answer
A. Current Flows During Both The Positive And Negative Half Cycles For A Conduction Angle Of 360 Degrees
Explanation
Class A amplifier operation is characterized by current flowing during both the positive and negative half cycles of the input waveform, covering a conduction angle of 360 degrees. This means that the amplifier conducts current throughout the entire input waveform, resulting in a high level of linearity and low distortion. This makes Class A amplifiers suitable for applications that require high-quality audio reproduction, although they are less efficient compared to other amplifier classes.
12.
What stage of a vacuum tube amplifier is the most sensitive to hum and noise?
Correct Answer
A. Input Stage
Explanation
The input stage of a vacuum tube amplifier is the most sensitive to hum and noise. This is because it is the first stage where the audio signal is introduced to the amplifier. Any interference or noise picked up at this stage will be amplified along with the audio signal, resulting in a degraded signal quality. Additionally, the input stage is responsible for amplifying the weakest signals, so any hum or noise present at this stage will be more noticeable compared to other stages.
13.
What does the term "hybrid" mean in the context of power amplifier technology?
Correct Answer
A. A Power Amp That Combines Vacuum Tubes And Solid State Devices In The Input And Output Stages
Explanation
The term "hybrid" in the context of power amplifier technology refers to a power amp that combines vacuum tubes and solid-state devices in the input and output stages. This means that the amplifier utilizes both traditional vacuum tube technology and modern solid-state technology to achieve a desired sound output. The combination of these two technologies allows for a unique blend of warm and rich tones from the vacuum tubes, and the reliability and efficiency of solid-state devices.
14.
What is the main difference between MOSFET output devices and bipolar junction transistors?
Correct Answer
B. Mosfets Are Biased By Voltage Rather Than Current
Explanation
MOSFET output devices and bipolar junction transistors differ in terms of how they are biased. While bipolar transistors are biased by current, MOSFETs are biased by voltage. This means that the operation of MOSFETs is controlled by the voltage applied to the gate terminal, whereas the operation of bipolar transistors is controlled by the current flowing through the base terminal. This difference in biasing method affects the overall performance and characteristics of the two types of transistors.
15.
What does the term "bridging" mean in amplifier terminology?
Correct Answer
C. A Way Of Connecting A Stereo Amplifier To Double Output Power
Explanation
The term "bridging" in amplifier terminology refers to a way of connecting a stereo amplifier to double the output power. This is achieved by combining the power from both channels of the amplifier into a single output, effectively increasing the power delivered to the speakers. By bridging the amplifier, it is possible to drive more demanding speakers or achieve higher volume levels.
16.
Why are field effect transistors (FETs) commonly used in the input stage of a power amplifier?
Correct Answer
A. They Offer High Input Impedance And Low Noise
Explanation
Field effect transistors (FETs) are commonly used in the input stage of a power amplifier because they offer high input impedance and low noise. The high input impedance allows for efficient transfer of signals from the input source to the amplifier, minimizing signal loss. Additionally, FETs have a lower noise level compared to other types of transistors, resulting in a cleaner and more accurate amplification of the input signal. Therefore, using FETs in the input stage helps to maintain the fidelity and quality of the amplified output signal.
17.
A power amplifier with a high output impedance will have a low damping factor. What is the definition of damping factor?
Correct Answer
D. The Ability To Control Woofer Cone Motion In A Loudspeaker
18.
Which of the following is not a true fact about class B amplifiers?
Correct Answer
B. They Have A Higher Efficiency Than Class C Amplifiers
Explanation
Class B amplifiers do not have a higher efficiency than Class C amplifiers. Class C amplifiers are known for their high efficiency, as they only conduct for a small portion of the input signal cycle. In contrast, Class B amplifiers have a conduction angle of 180 degrees, meaning they conduct for the entire input signal cycle, resulting in lower efficiency compared to Class C amplifiers.
19.
Which of the following is a class A amplifier?
Correct Answer
D. Vox Ac30
Explanation
The Vox AC30 is a class A amplifier because it operates in a single-ended configuration, meaning that the output signal is produced by a single active device (usually a vacuum tube). Class A amplifiers are known for their warm and rich tone, as well as their simplicity in design. They provide a full and smooth sound, making them popular among guitarists. The other options mentioned (Mesa/Boogie Heartbreaker, Fender Twin, and Marshall JCM 2000) are not specifically class A amplifiers, as they can operate in different amplifier classes depending on the specific model and settings.
20.
What guitar and amplifier company makes the "Can" amp?
Correct Answer
D. Fender
Explanation
Fender is the correct answer because Fender is a well-known guitar and amplifier company that has been in the industry for many years. They are known for producing high-quality instruments and amplifiers that are used by professional musicians worldwide. The "Can" amp is likely one of their products, indicating that Fender is the company that makes it.
21.
In a spread spectrum communication system, what is an approximation of processing gain?
Correct Answer
C. Chip Rate Divided By Data Rate
Explanation
Processing gain in a spread spectrum communication system can be approximated by dividing the chip rate by the data rate. This approximation is based on the fact that the chip rate represents the rate at which the spreading code is transmitted, while the data rate represents the rate at which the actual information is transmitted. By dividing the chip rate by the data rate, we get an estimate of the increase in signal power due to the spreading process, which is known as the processing gain.