Audio Database

AT-3000
Commentary

Line controller using a 23-step trans-type attenuator for level control.

While general attenuators generally use the attenuation characteristics of resistors, the AT-3000 is equipped with a line signal transformer that is Shinkai generated for the attenuator in consideration of the influence of DC resistance components that enter the signal line in series on sound quality.
By taking out 23 steps from the secondary winding of the transformer and switching each level with a high-precision rotary switch, resistors can be completely eliminated and direct current resistance is minimized.

The TRANSFORMERS for the attenuator uses a multi-layered structure of 0.2 mm nickel super-permalloy based on numerous prototypes and listening tests. We have also introduced our unique know-how on how to take out the intermediate tap on the winding, and have realized a high-purity line signal transformer.

For the mounting of the transformer, we have adopted an attachment made of maple based on the idea that it is magnetically hollow but mechanically firmly supported. This attachment has been carefully designed to unify the direction of the wood grain.
In addition, in order to prevent induction from the outside, it has a double structure with a pure copper inner shield cabinet inside the main body chassis.

It has a unique demagnetizer function that uses the energy of the music signal itself to demagnetize the core, thus keeping the attenuator transformer in good condition.

Equipped with two coaxial outputs and one European standard XLR balanced output.
For the pin terminal used for the coaxial output, a newly developed special part with excellent reliability and durability is used. The metal part is finished with brass machined copper base metal plating, and Teflon material is used for the insulation part, making it a high quality product.
The XLR output is a floating type and a balanced connection may not be suitable for some models.

Four input terminals and one direct input terminal are installed.
A 6N high-purity copper material is used for the internal wiring, and not only the hot side of the signal line but also the ground circuit is switched. The direct input is intended for use with only one source, so it can pass through the selector function and be directly connected to the attenuator.

The front panel has a 10 mm thick hairline finish, and the attenuator knob is machined from solid wood.
The rear panel also uses a thick hairline panel similar to the front panel.

Model Rating
Type Transformer type line controller
Frequency characteristic 20 Hz ~ 20 kHz ± 2 dB or Less (at 10k Ω Load)
Maximum boost ratio 1:1.3
Attenuation -60dB for maximum value, 23 contacts
Maximum input level 5Vmax(20Hz)
DC resistance (25 ° C) Primary : 100 Ω
Quadratic : 160 Ω
Attachment mechanism De Magnesaizer
Earth switch
Ground terminal
External dimensions Width 250x Height 111x Depth 345 mm
Weight 5.9kg