Mingdan 2A3 and its applications 03

It is now a consensus that negative feedback does more harm than good to sound quality. However, there are very few amplifier devices that can work stably without negative feedback
. The open-loop characteristics of 2A3 are very ideal. When there is no negative feedback, the operation is stable, which is undoubtedly
helpful for reducing TIM, IIM and PIM distortion. Figure 1-19 shows the single-tube Class A amplification circuit that has become popular among Japanese fans in recent years. The icon
components have been replaced with the same domestically produced components . The circuit is simple, has few components , and is easy to make. Its sound is charming, and its rich taste is overwhelming
[Lu Ertu]. 20. Figure 1-zl shows push-pull amplification, with
output power from io to isw. The circuit in Figure 1-20
is often produced among gallbladder fans, and it sounds extraordinary. I wonder if it benefits
Shaodan 6N11. The circuit with the most feverish flavor that needs to be verified
may be the circuit shown in Figure 1.21. Due to the use
of a push transformer , the number of components is surprisingly small, with only 5 resistive and capacitive
components . The inverted signal of this line
is strictly symmetrical, and the excitation voltage can be overloaded without changing the bias voltage and affecting the operating
point. It has quite high fidelity and is superior in terms of listening experience - but the push transformer
used for phase inversion is more difficult to make and commercially available products are expensive, which is its shortcoming .