Differential amplifiers tend to cancel distortions that single-ended amplifiers cannot. Drift is reduced by the tight coupling of the two halves of the amplifier. Performance over time is improved. Common-mode rejection ratio is the measurement of a differential amplifier's ability to not amplify noise that is common to both inputs. It is typically at least 55 dB, and can approach 140 dB in some critically-tuned designs.
Differential amplification takes more parts to execute.
On the bench, in the textbook and in real life, differential amplification provides greater performance, particularly from DC to 100 KHz, the audio region. Reliability in practical terms equals or exceeds that of conventional single-ended circuits, if designed properly. Cascode Amplifiers Cascode amplifiers are another method of using two triodes in a single stage of gain. The top tube is arranged as a constant current source, which has the effect of acting like the circuit of Figure 1 with a very large plate resistor and a very high plate voltage. In this arrangement, the gain and linearity are substantially improved over basic triode amplifiers.