The amplifier is the interface between your signal sources and the speaker system, whatever is lost at this position is lost forever and conversely, whatever is introduced is also amplified. Amplifiers are also products for everyday use. Some successfully deviate from the conventional, they remind us of the strive for perfection – a human virtue we like to recognize and being close to.
There is a distinctive mood of luxurious puritanism to be found in the appearance of most Copland amplifiers. However, with the CTA407 tube amplifier we have compromised simplicity, introducing a fair deal of electronics supporting the audio stages of the amplifier.
The forty LED diodes on the front panel (10 for each tube) are the visual part of the CTA407 tube bias and diagnostic system. And yes, the LEDs can be turned off if you don’t want to read the status of your power tubes on the fly.
The CTA407 will automatically adjust for any tube in the 6550/KT88/KT120/KT150 family. The CTA407 servo system is not only a lossless automatization of the bias adjustment – it is an integrated part of the CTA407 internal high pass filtering, closely matched to the transfer function of the amplifying circuitry and a vast improvement to the overall fidelity of the amplifier.
The CTA407 employs five line-level inputs including a tape monitor loop and a built-in RIAA phono circuit accommodating moving magnet, as well as high output moving coil cartridges. It is a development of the CTA405 amplifier, an object of desire for audiophiles worldwide since its launch more than a decade ago.
The push pull output stages consist of a pair of matched power tubes in fixed ultra linear configuration, providing the low distortion of triodes and the power of tetrode valves. A pair of 6550 or KT-family tubes in push-pull configuration can deliver more than 100W of audio power. Moderating the power output, the CTA407 delivers 2x50W in high biased class A/AB mode. In practice, this means that the amplifier can deliver most its power in class A state.
Due to the quality of the output transformers, superb linearity is achieved before feedback is employed, reducing the requirements for internal lag compensation networks, and ensuring high stability after the 18dB negative feedback loop is closed.
The CTA407 can provide an extraordinarily accurate reproduction of music without tendency towards listening fatigue, featuring strong dynamics and a wide flexibility in the choice of speakers. The vanishing low perceived noise from the amplifier itself is a bliss, especially for owners of high efficiency speaker systems.
The CTA407 employs motor driven volume control and can be fully controlled by the Copland RC102A remote control unit.