The Copland CTA-408 integrated amplifier is designed for those who want to combine all their amplification components in one package, but expect the performance of individual units. It offers nice features such as separate MC and MM phono inputs, monitoring I/Os, a headphone amplifier and a soft start procedure that greatly extends tube life.
Technology has advanced in recent decades, offering new possibilities for circuit optimization using components and manufacturing processes largely unavailable to tube amplifier designers.
In the amplifier stage, the lamps are assisted by MOSFET transistors. The power system consists of several individual power supplies operating with constant current – in this way, the developers managed to avoid transmitting current fluctuations to the input stage. The phono preamp is powered by J-FET transistors with an active RIAA equalization curve using over a hundred discrete components located under a protective casing. The output transformers are designed by Copland.
Of the tubes, there are four KT150s, which, according to the developers, allow tube devices to play in the same field that is dominated by transistor solutions. They are assisted by 12BH7. The lamps are visible through the slots in the front panel. The amplifier power is 75 W per channel into 8 ohms.
Features of Copland CTA-408
The driver tube stage is supported by MOSFET circuits.
Multiple individual power supplies designed to operate at constant power help isolate the input stages from the output stages and eliminate back modulation towards the power supply.
Separate Class A headphone amplifier, (speaker output is muted when headphones are connected)
Excellent J-FET Phono preamp. Active RIAA correction uses more than a hundred discrete elements inside its own soundproof box.
Copland’s proprietary output transformers, tuned to the optimum power range. Massive cores prevent saturation, and the transformers are capable of delivering full power to the speakers even at frequencies below 20Hz with minimal phase shift. Multiple layers of alternating windings provide excellent linearity. Improved high-frequency performance reduces the need to compensate for internal delays as amplifier feedback depth approaches 15 dB.
The amplifier’s power is based on a foundation of KT150 tubes. These tubes are later iterations of the legendary 6550/KT88 tubes, and in the Copland CTA-408 they confidently demonstrate that the famous tube sound can venture into territory currently dominated by solid-state circuit design.
Huge, powerful tubes are always a sight to behold, so we decided to make them visible through the horizontal perforations of the front panel, creating a stunning appearance that matches the amazing sound of the amp.
Specifications Copland CTA-408
Tubes: KT150 (4pcs.)
12BH7 (2pcs.)
6072A / 12AY7 (2pcs.)
Output power: 75 W per channel
THD: < 0.9%
Frequency response: 5Hz-100kHz (-3 dB)
Input sensitivity: Phono: 3.0 mV (MM) / 0.26 mV (MC)
Line Inputs: 250 mV
Input Impedance: Phono: 47 kΩ (MM) / 50, 100, 470 Ω (MC)
Line Inputs: 50 kΩ
Load Impedance: 8 Ohm, 4 Ohm
Signal-to-noise ratio: >90 dB
Feedback depth: 15 dB
Phase: Not inverted
Frequency response
(headphone amplifier): 10Hz-200kHz (-3 dB)
Gain
(headphone amplifier): 17.5 dB
Output impedance
(headphone amplifier): 9 Ohm
Power consumption: up to 400 W
Dimensions (mm): 435 (W), 220 (H), 460 (D)
Weight (packed): 26 kg
