Yamamoto Sound Craft
AT-03-3A Passive Attenuator

The overwhelming amount of information and the warmth in the high frequency range characteristic of passive attenuators are complemented by a soft and warm tone. The sound is light, delicate, bright, and pleasant.

The AT-03-1A and AT-03-3A attenuators have a volume control function called "L type" that switches 28 points of resistors. The L-pad type has only two resistors that enter the signal source, minimizing the sound quality loss caused by the resistors. Losses due to passing resistors are minimized by the use of surface-mount resistors, and almost no noise is generated when switching contacts.

The step interval of each switch point can be adjusted from 0 dB to -38 dB in 2 dB steps, allowing fine adjustment. The minimum volume can be reduced to -65dB, allowing for any level adjustment. The left/right level deviation at each volume setting is effectively within 0.2 dB, successfully minimizing the weak point of continuous volume units, the negligibly small left/right level difference. The impedance is set at 50kΩ, an impedance that can be connected to any equipment.

The volume control switch and input switch of this unit are 45SD type made by Seiden Corporation, which has an established reputation for reliability and usability. For the resistors in the volume control section, 1W type surface mount resistors manufactured by DALE of the U.S.A. are used after numerous audition tests. For the internal wiring of the unit, 1.2mm-diameter high-purity 6N single copper wire was used for all wires. The wires are used in Teflon tubing with the best insulation properties.
For the internal wiring of the unit, 1.2mm-diameter high-purity 6N single copper wire was used for all wires. The wires are enclosed in Teflon tubing with the best insulation properties.

The dials and feet are made of ebony.

Type	28-step volume control attenuator
Impedance	50kΩ
Input System Input	3 inputs only
Outputs	2 outputs only
Input switch	Yes
Dimensions	200(W) 270(D) 97(H) mm
Weight	2.5 kg

I was expecting a passive attenuator without an amplification circuit like a preamplifier to have a light sound in the mid-high range, but I did not find it lacking in the bass range as much as I had been led to believe. The sharpness of the rise and fall of the sound was sharp, the spatial resonance was clear, and the instruments were well separated, conveying a sense of the atmosphere of the scene. The air flow from the brass instruments could be felt, and the female vocals, which had good bounce and extended to high notes, were vividly rendered. There is no sense of loss of sound when the volume is turned down. The bass is sufficient for those who are not particular about the bass range.