Final answer:
A direct coupled amplifier has a disadvantage of being susceptible to DC offset and drift, potentially leading to performance and stability issues.
Step-by-step explanation:
The disadvantage of a direct coupled amplifier, while it has good frequency response at very low frequencies, is its susceptibility to DC offset and drift problems. Unlike capacitors, which block DC and can stabilize the amplifier over time, direct coupling allows any DC bias from earlier stages or components to pass through, potentially causing issues with performance and stability. Additionally, amplifiers with direct coupling may require more complex servo mechanisms to mitigate these effects, which can increase design complexity and cost.
The advantage of a direct coupled amplifier is good frequency response at very low frequencies. However, the disadvantage is that it can't amplify or transmit high frequencies effectively. This is because at high frequencies, the reactance of the inductor becomes large, impeding the current flow through it. As a result, the high frequencies are impeded and not amplified properly in a direct coupled amplifier.