FIG. 27 provides a further improvement to the circuit in FIG. 26 and or FIG. 25 by providing additional amplifier A5 and or A6. Finite base currents from Q3 and or Q4 can result in voltage drops across R6, R7, R8, and or R9, which can result in extra distortion (e.g., in a voltage controlled amplifier). Amplifiers A5 and or A6 that include low output impedance or resistance can provide voltage to the base of Q3 and or Q4 without regard or consequence (e.g., performance degradation such as generating distortion) to the base current from Q3 and or Q4. The collector of transistor Q5 provides a signal current and a bias current, and the collector of Q5 may be replaced with an equivalent circuit having a DC current and an AC signal current. In another embodiment one or more amplifiers, A1, A2, A3, and or A4 may be replaced, and or one or more amplifiers, A1, A2, A3, and or A4 input to output terminals may be coupled through with a wire or coupling element. For example, in FIG. 26, amplifiers A2 and or A4 can be replaced or removed, and the lower terminal of resistor R7 that was connected to o2 of A2 is now coupled to the collector of Q5 and or the lower terminal of resistor R9 that was connected to o4 of A4 is now connected to a signal source such as the collector of Q5.
