Post by jlafrenz on Aug 21, 2011 22:39:56 GMT -5
In an attempt to provide a better understanding to amplifiers and how they work along with some frequently asked questions, this sticky has been created for everyone's general knowledge. Please keep in mind that this sticky is a work in progress (and probably always will) and that new information will be added to it as necessary. So that means if there is info you would like to add, no answer to your question or any other changes to be made, please PM a moderator and the changes will be made accordingly. Enjoy!
Note: The following is a subset of terminology - i.e. the terms that pertain to amplification. For a full list of terminology, please refer to: emotivalounge.proboards.com/index.cgi?action=display&board=tech&thread=19276&page=1#306273
Amplification Terminology
Bi-amping - Using two power amplifiers to drive on loudspeaker. One amplifier typically drives the woofer, the second drives the midrange and tweeter.
Bridging - Amplifier-to-loudspeaker connection method that converts a stereo amplifier into a monoblock power amplifier. One amplifier channel amplifies the positive half of the waveform, the other channel amplifies the negative half. The loudspeaker is connected as the "bridge" between the two amplifier channels.
Capacitance - Capacitance, in electricity, is the capability of a body, system, circuit, component or device for storing electric charge. Capacitance is expressed as the ratio of a stored charge in coulombs to the impressed potential difference in volts. The resulting unit of capacitance is designated as the farad. In an electric circuit the component device designed to store such an charge is called a capacitor .
Capacitor - Electronic component that stores a charge of electrons. Reservoir capacitors are used for energy storage in amplifiers, filter capacitors filter traces of AC from DC power supplies; coupling capacitors connect one amplifier stage to another by blocking DC and allow signal to pass.
Crosstalk (channel Separation) - A measure of how well sounds in one channel are isolated from the other channel.
Current - The flow of electrons in a conductor. For example, a power amplifier "pushes" electrical current through speaker cables and the voice coils in a loudspeaker to make the move back and forth.
Damping factor - A number the expresses a power amplifier's ability to control woofer motion. Related to the amplifier's output impedance.
DC (Direct Current) - Flow of electrons that remains steady rather than fluctuating. Contrasted with alternating current (AC).
Differential amplifier - electronic circuit that amplifies only the difference between the two phases of the balanced signal.
Feedback - In amplifier circuits, taking part of the output signal and sending it back to the amplifier's input. Feedback reduces distortion and makes the circuit more stable.
Frequency Response - A graphical representation showing a device's relative amplitude as a function on frequency.
Gain - Number expressing the amount of amplification provided by and amplifier. An amplifier that converts a signal with an amplitude of 0.1V to 1V is said to have a gain of 10.
Impedance - Resistance to the flow of AC electrical current. An impedance is a combination of resistoance, inductive reactance, and capacitive reactance.
Input impedance - The resistance to current flow presented by a circuit or component to the circuit or component driving it. Impedance is a combination of resistance, capacitive reactance, and inductive reactance.
Integrated amplifier - Audio product combining a preamplifier and power amplifier in one chassis.
Monoblock - An amplifier with only one channel.
Multichannel power amplifier - A power amplifier with more than two channels.
Ohm - The unit of resistance to electrical current flow.
Output impedance - Technically, the change in a component's output voltage in response to a change in load impedance. Practically, a component with a high output impedance can deliver less current to a load than a component with a low output impedance.
Power amplifier - An audio component that boosts a line-level signal to a powerful signal that can drive loudspeakers.
Power output - A measure of a powers amplifier's ability, in watts, to deliver electrical voltage and current to a speaker.
Power supply - Circuitry found in every audio component that converts 60Hz alternating current from the wall outlet into direct current that supplies the audio circuitry.
Power transformer - Device in a power supply that reduces the incoming voltage from 120V to a lower value.
Push-pull amplifier - Amplifier in which pairs of transistor or vacuum tubes are arranges so that one transistor or tube amplifies the positive half of the audio waveform, and the other tube amplifies the negative half. Contrasted with single-ended amplifier.
Rail - The power-supply voltage fed to the audio circuits
Rectifier - A device that converts AC current into DC current. Found in all power supplies.
Signal-to-noise ratio - Numerical value expressing in decibels the difference in level between an audio component's noise floor and some reference signal level.
Single-ended amplifier - Amplifier in which both half-cycles of the audio waveform are amplified by the output tube or transistor. Contrasted with "push-pull amplifier."
Voltage - Analogous to electrical pressure. Voltage exists between two points when one point has an excess of electrons in relation to the other point. 1 volt across 1 ohm of resistance produces a current of 1 Ampere.
Watt - The unit of electrical power, defined as the power dissipated by 1 Ampere of current flowing through 1 ohm of resistance.
Amplifier Classes
For a basic understanding of the types of amplifier classes, please click the link below to the Audioholics website below.
www.audioholics.com/education/amplifier-technology/audio-amplifier-classes
For more advanced information about amplifier classes, please click the link below.
www.electronics-tutorials.ws/amplifier/amp_1.html
FAQ
Can I use speakers with different impedance's on the same amp?
Yes, this will work with Emotiva amps.
Should I use balanced (XLR) or unbalanced (RCA)?
This will depend on the other gear you own and the connections they offer. Typically most gear will have unbalanced (RCA) connections and this most common used cable and works for the majority of setups. Some gear, including several Emotiva components, offer balanced connections. Please note that just because a piece of gear has an XLR balanced connection does not mean that it is a fully balanced design. Balanced (XLR) cables are typically better for longer runs, avoiding line noise and interference or for systems that have fully balanced components. There are several quality unbalanced (RCA) cables out there that provide resistance to line noise and interference though. Keep in mind that a cable that is balanced (XLR) on one end and unbalanced on the other (RCA) is still an unbalanced cable and would not provide the benefits of a balanced (XLR) cable. Which ever you choose, make sure the switch on the back of the amp corresponds to the type of cable you have chosen.
How do I connect X-Series speaker cables to my XPA-1?
Typically the banana is connected into the end of the binding post. In this situation, unscrew the binding post and take notice of the hole present in the side of the post. Stick the banana plug through the hole and tighten down.
Can I plug my amp into a surge protector?
It is recommended by Emotiva to plug your amplifier directly into a wall outlet. That being said, several Emotiva users have used their amps in conjunction with surge protectors without issue. If you decide to plug your amp into a surge protector, make sure to use the proper bank of outlets labeled high current on your surge protector. Common, everyday household surge protectors may limit the current to the amp while HT designed units such as APC, Panamax, Monster, etc... will have outlet banks specifically designed for such applications. These banks of outlets do not limit the current to the amp which the need to perform to specified capabilities.
Do I need a dedicated 15/20 Amp circuit for my amp?
It is not necessary to have dedicated circuits as long as you are not overloading your current one(s). However, if you have the time, funds and or capabilities to run a dedicated circuit, it sure doesn't hurt so go for it.
Can I stack my amps?
Yes, you can stack your amps on top of each other.
Can I stack my AVR or other source components on the amp?
Yes. The amp will hold the weight of an AVR or other source components. Just make sure that the feet of the component on top allow enough room for air flow on top of the amp.
*References
-The Complete Guide to High-End Audio by Robert Harley
- www.csgnetwork.com/glossary.html
Note: The following is a subset of terminology - i.e. the terms that pertain to amplification. For a full list of terminology, please refer to: emotivalounge.proboards.com/index.cgi?action=display&board=tech&thread=19276&page=1#306273
Amplification Terminology
Bi-amping - Using two power amplifiers to drive on loudspeaker. One amplifier typically drives the woofer, the second drives the midrange and tweeter.
Bridging - Amplifier-to-loudspeaker connection method that converts a stereo amplifier into a monoblock power amplifier. One amplifier channel amplifies the positive half of the waveform, the other channel amplifies the negative half. The loudspeaker is connected as the "bridge" between the two amplifier channels.
Capacitance - Capacitance, in electricity, is the capability of a body, system, circuit, component or device for storing electric charge. Capacitance is expressed as the ratio of a stored charge in coulombs to the impressed potential difference in volts. The resulting unit of capacitance is designated as the farad. In an electric circuit the component device designed to store such an charge is called a capacitor .
Capacitor - Electronic component that stores a charge of electrons. Reservoir capacitors are used for energy storage in amplifiers, filter capacitors filter traces of AC from DC power supplies; coupling capacitors connect one amplifier stage to another by blocking DC and allow signal to pass.
Crosstalk (channel Separation) - A measure of how well sounds in one channel are isolated from the other channel.
Current - The flow of electrons in a conductor. For example, a power amplifier "pushes" electrical current through speaker cables and the voice coils in a loudspeaker to make the move back and forth.
Damping factor - A number the expresses a power amplifier's ability to control woofer motion. Related to the amplifier's output impedance.
DC (Direct Current) - Flow of electrons that remains steady rather than fluctuating. Contrasted with alternating current (AC).
Differential amplifier - electronic circuit that amplifies only the difference between the two phases of the balanced signal.
Feedback - In amplifier circuits, taking part of the output signal and sending it back to the amplifier's input. Feedback reduces distortion and makes the circuit more stable.
Frequency Response - A graphical representation showing a device's relative amplitude as a function on frequency.
Gain - Number expressing the amount of amplification provided by and amplifier. An amplifier that converts a signal with an amplitude of 0.1V to 1V is said to have a gain of 10.
Impedance - Resistance to the flow of AC electrical current. An impedance is a combination of resistoance, inductive reactance, and capacitive reactance.
Input impedance - The resistance to current flow presented by a circuit or component to the circuit or component driving it. Impedance is a combination of resistance, capacitive reactance, and inductive reactance.
Integrated amplifier - Audio product combining a preamplifier and power amplifier in one chassis.
Monoblock - An amplifier with only one channel.
Multichannel power amplifier - A power amplifier with more than two channels.
Ohm - The unit of resistance to electrical current flow.
Output impedance - Technically, the change in a component's output voltage in response to a change in load impedance. Practically, a component with a high output impedance can deliver less current to a load than a component with a low output impedance.
Power amplifier - An audio component that boosts a line-level signal to a powerful signal that can drive loudspeakers.
Power output - A measure of a powers amplifier's ability, in watts, to deliver electrical voltage and current to a speaker.
Power supply - Circuitry found in every audio component that converts 60Hz alternating current from the wall outlet into direct current that supplies the audio circuitry.
Power transformer - Device in a power supply that reduces the incoming voltage from 120V to a lower value.
Push-pull amplifier - Amplifier in which pairs of transistor or vacuum tubes are arranges so that one transistor or tube amplifies the positive half of the audio waveform, and the other tube amplifies the negative half. Contrasted with single-ended amplifier.
Rail - The power-supply voltage fed to the audio circuits
Rectifier - A device that converts AC current into DC current. Found in all power supplies.
Signal-to-noise ratio - Numerical value expressing in decibels the difference in level between an audio component's noise floor and some reference signal level.
Single-ended amplifier - Amplifier in which both half-cycles of the audio waveform are amplified by the output tube or transistor. Contrasted with "push-pull amplifier."
Voltage - Analogous to electrical pressure. Voltage exists between two points when one point has an excess of electrons in relation to the other point. 1 volt across 1 ohm of resistance produces a current of 1 Ampere.
Watt - The unit of electrical power, defined as the power dissipated by 1 Ampere of current flowing through 1 ohm of resistance.
Amplifier Classes
For a basic understanding of the types of amplifier classes, please click the link below to the Audioholics website below.
www.audioholics.com/education/amplifier-technology/audio-amplifier-classes
For more advanced information about amplifier classes, please click the link below.
www.electronics-tutorials.ws/amplifier/amp_1.html
FAQ
Can I use speakers with different impedance's on the same amp?
Yes, this will work with Emotiva amps.
Should I use balanced (XLR) or unbalanced (RCA)?
This will depend on the other gear you own and the connections they offer. Typically most gear will have unbalanced (RCA) connections and this most common used cable and works for the majority of setups. Some gear, including several Emotiva components, offer balanced connections. Please note that just because a piece of gear has an XLR balanced connection does not mean that it is a fully balanced design. Balanced (XLR) cables are typically better for longer runs, avoiding line noise and interference or for systems that have fully balanced components. There are several quality unbalanced (RCA) cables out there that provide resistance to line noise and interference though. Keep in mind that a cable that is balanced (XLR) on one end and unbalanced on the other (RCA) is still an unbalanced cable and would not provide the benefits of a balanced (XLR) cable. Which ever you choose, make sure the switch on the back of the amp corresponds to the type of cable you have chosen.
How do I connect X-Series speaker cables to my XPA-1?
Typically the banana is connected into the end of the binding post. In this situation, unscrew the binding post and take notice of the hole present in the side of the post. Stick the banana plug through the hole and tighten down.
Can I plug my amp into a surge protector?
It is recommended by Emotiva to plug your amplifier directly into a wall outlet. That being said, several Emotiva users have used their amps in conjunction with surge protectors without issue. If you decide to plug your amp into a surge protector, make sure to use the proper bank of outlets labeled high current on your surge protector. Common, everyday household surge protectors may limit the current to the amp while HT designed units such as APC, Panamax, Monster, etc... will have outlet banks specifically designed for such applications. These banks of outlets do not limit the current to the amp which the need to perform to specified capabilities.
Do I need a dedicated 15/20 Amp circuit for my amp?
It is not necessary to have dedicated circuits as long as you are not overloading your current one(s). However, if you have the time, funds and or capabilities to run a dedicated circuit, it sure doesn't hurt so go for it.
Can I stack my amps?
Yes, you can stack your amps on top of each other.
Can I stack my AVR or other source components on the amp?
Yes. The amp will hold the weight of an AVR or other source components. Just make sure that the feet of the component on top allow enough room for air flow on top of the amp.
*References
-The Complete Guide to High-End Audio by Robert Harley
- www.csgnetwork.com/glossary.html
