Difference between revisions of "Amplifier classes"

From LinnDocs
Jump to: navigation, search
m
m
 
(23 intermediate revisions by the same user not shown)
Line 1: Line 1:
 +
__TOC__
 
==Class A-B==
 
==Class A-B==
: This is a mixture of Class A and Class B amplifiers
+
{{info:Class-A-B description}}
::<u>Class A</u>: Where there is '''a''' large transistor that is on all of the time. The issue with Class A is that it is not power efficient this can be as low as 30% and will produce a lot of heat. That is, if you had a speaker driven at 30W power, in the worst case 70W of power would be used <b>WITHIN</b> the amplifier, This energy is output as heat). Even if there is no signal then there is a significant ldling power.<br><br>
+
<br><br>
::<u>Class B</u>: This are '''two''' large transistors in a ''push-pull'' setup. In this case  there is only one transistor is on at time, one for postive sections of the waveforms and one for the negative sections of the waveform. However, in this configuration there is distortion as there is a gap between one power transistor switching off and the other transisitor switching on when the incoming signal goes from the positve section to the negative section. This is called <b>zero-crossing distortion</b>.
+
Some of the Linn products included in this class are:  
:Class A-B combines these classes but keeps a more efficient power handling, typically 50-60% efficient, and adds a <i><q>bias</q></i> to <u>remove</u> the  <b>zero-crossing distortion</b> and keep a linear signal. In Linn amplifiers this is typically the amplifier negative is tied to ground/earth and only the positive terminal changes voltage.
+
{{block indent|{{#categorytree:Class_AB_Amplifier|hideroot|mode=pages}} }}
: In other words:
+
<hr>
::<u>Class A</u>: Sounds good, but uses a lot of power all of the time
 
::<u>Class B</u>: Sounds OK, but doesn't uses much less power than Class-A.
 
::<u>Class A-B</u>: Sounds good and but doesn't break the bank on Electricity/power bills.
 
 
 
 
==Class Chakra==
 
==Class Chakra==
:{{info:Chakra operation}}
+
{{info:Chakra operation}}
  
 +
:<i>Some</i> of the Linn products included in this class are:
 +
{{block indent|{{#categorytree:CHAKRA_Class_Amplifier|hideroot|mode=pages}} }}
 +
<hr>
 
==Class D==
 
==Class D==
: This is <b><u>NOT</u></b> a digital amplifier. This uses voltage pulses at a very high frequency and different pulse widths. This coupled with a inductive/capacitive load will produce a voltage. These amplifiers have an efficiency of better then 85% (e.g. 85W to speaker, 15% used in amplifier, a lot less heat than Class-A).
+
{{info:Class-D description}}
: As the amplifier is dependant on the inductive/capative load then the usual loading of Electrostatic loudspeakers may cause poor sounding instability. Check with your speaker manufacturer for any solutions.
 
: In Linn amplfiers using Class-D the outputs are bridged, that both speakers output terminal change voltage. If you plan to use a Sub-woofer amplifier that
 
  
  
 +
:The Linn products included in this class are:
 +
{{block indent|{{#categorytree:Class-D Amplifier‏‎|hideroot|mode=pages}} }}
 +
<hr>
 
[[Category:FAQ's]]
 
[[Category:FAQ's]]

Latest revision as of 14:50, 15 September 2023

Class A-B

This is a mixture of Class A and Class B amplifiers
Class A: has a large transistor that is on all the time. These amplifiers are linear but are not very power efficient, (can be as low as 30%) and will produce a lot of heat. That is, if you had a speaker driven at 30W power, in the worst case 70W of the amplifier power would be used WITHIN the amplifier, This energy is output as heat). Even if there is no signal, then there is a significant idling power.

Class B: has two large transistors in a push-pull setup. These are more efficient, typically 50-60%, but not as linear and produce zero-crossing distortion.

Class A-B combines these classes but keeps a more efficient power handling, typically 50-60% efficient, and adds a bias to remove the zero-crossing distortion and keep a linear signal.
In Linn amplifiers this is typically the amplifier negative is tied to ground/earth and only the positive terminal changes voltage.

In other words:
Class A: Sounds good, but uses a lot of power all the time
Class B: Sounds OK, but doesn't use much less power than Class-A.
Class A-B: Sounds good and doesn't break the bank on Electricity/power bills.



Some of the Linn products included in this class are:



Class Chakra

The Chakra amplifier design uses an array of large transistors as ‘boosters’ around a single chip integrated circuit. When output current is less than a few amps all the power output comes from the single chip circuitry, maximising the speed and linear properties of this design. At higher output currents the transistors provide the majority of the output current, leaving the integrated circuit to operate well within its capability and able to correct any error instantaneously.
The design is very compact, reducing the circuit area and length of the signal path and is also highly efficient, producing much less heat than traditional designs.
Linn Power Amplifier Chakra white paper
Some of the Linn products included in this class are:


Class D

This is NOT a digital amplifier. The Class D amplifier uses very high-speed switches to send the entire voltage of the power supply, with minimal power loss, as a sequence of pulses to the output, where a filter averages the pulses before the loudspeaker terminals. The frequency, density and duty cycle of these pulses determine the average output voltage. This is designed to have an inductive/capacitive load of a standard coil loudspeaker and have an efficiency of better than 85% (e.g. 85W to speaker, 15% used in amplifier, a lot less heat than Class-A).
As the amplifier is dependent on the inductive/capative load, then the usual loading of Electrostatic loudspeakers may cause poor sounding instability. Check with your speaker manufacturer for any solutions.

In Linn amplifiers using the Class-D amplifier, the outputs are bridged, that is, both RED and BLACK speaker output terminals change voltage.
  • As a precaution, do NOT connect/disconnection anything from the Amplifier output terminals UNLESS the amplifier is in Standby/Sleep state
  • If you plan to use a Sub-woofer amplifier that uses the power amplifier output terminals, then make sure that the Sub-woofer is set up for bridged amplifiers.


The Linn products included in this class are: