Ability Vacuum Tube Preamplifier AT-4
This is a 4 channel vacuum tube preamplifier that reproduces the warm analog feeling as it is.
By connecting the AT-4 to the middle stage between the main source unit and the amplifier, the AT-4 only changes to a stable and calm tone, and the texture of the sound is also very good.
It seems to be even better news for those who use the existing digital processor.

A well-designed vacuum tube amp has the advantage of being able to reproduce sound with excellent performance.
However, it was difficult to be applied to vehicles for various reasons, such as a power circuit to meet the operating voltage of a vacuum tube and noise due to high impedance.
However, MS Audio has released a tube preamplifier that overcomes these difficulties.

It is composed of an NF-type two-stage amplifier circuit, which has a clear and transparent sound quality improvement effect in the mid-range, and makes the cold image of a digital source into a warm, traditional analog sound quality. In particular, in the case of products that are listed as existing vacuum tube preamplifiers (workshop level), most of them use only one vacuum tube per channel and use only one stage after amplification. It was insufficient to express the unique tone of a vacuum tube. However, in the case of AT-4 developed by MS Audio, the circuit applied to Hi-End products for home is designed for the vehicle and produced through thorough quality control, providing excellent sound quality. In addition, when replacing with an old tube such as Siemens, Telefunken, RCA, or Mullard instead of the Sorbtec tube installed at the factory, you can experience the change of tone according to the vacuum tube, and it is easy to select the sound quality that suits the taste of the consumer.

This Pre Amp requires aging time.
When aging for at least 200 hours, the bandwidth is widened and the sound quality is improved.