1. Over the next two years they developed their first valve amplifier . 2. Valve amplifier circuits are significantly different from broadband solid state circuits.3. A particularly critical component is the output transformer of a valve amplifier . 4. Amateurs also use valve amplifiers in the 500-1500 watt range mainly for economic reasons. 5. Vacuum tube or electronic valve amplifiers were first used to resolve microphone impedance and output problems. 6. The DeVille features a 60-watt valve amplifier with three 12AX7 preamp valves and two 6L6 output valves. 7. Vacuum-tube amplifiers ( also known as tube amplifiers or valve amplifiers ) use a vacuum tube as the active device. 8. Amplifiers for harder, heavier genres often use valve amplifiers ( known as " tube amplifiers " in North America ) also. 9. Valve amplifiers have a tuned network that serves as both the low pass harmonic filter and impedance matching to the output load.10. A pair of Kershaw Kalee II arc film projectors with RCA sound heads and an RCA high fidelity 6-valve amplifier were installed.
