COPLAND CTA407 > Future-proof valve amplifier
Unlike the integrated hybrid amplifier CSA150, the CTA407 uses radio valves throughout the signal chain.
One ECC83 triode valve and two 12BH7 valves make up the pre-amplifier stage, while four KT88 or 6550 are used in the output section.
The four output valves are paired, one pair for each channel, and work in a push-pull configuration. Together they are capable of delivering more than 100 W of power per channel, but Ole Møller has deliberately chosen to reduce the power to 50 W per channel by increasing the bias current of the tubes in a class A/AB configuration, where the valves operate in class A with a higher power than normal for an AB configuration.
Conclusion
There are integrated amplifiers that provide greater detail and power, many of which have as many as 14 inputs, DAC and streaming. Many of these can be alternatives to the Copland CTA407, and in some areas they may play even better with even more control and power. But they rarely have the same fluid, lightweight warm glow as a CTA407. An integrated valve amplifier that you can enjoy for decades and that works with a wide range of radio valves. That’s an achievement in itself. So never mind that it doesn’t have a phono input for normal moving coil pickups.