Attn-2 Stereo 66-Step Stepped Attenuator

Attn-2 Stereo Stepped Attenuator Stepped attenuators deliver decisive clicks and precise attenuation. Sadly, they are never cheap—well, at least the high-quality ones are never cheap, as the switches with hard-gold contacts are expensive in the extreme. Thus, the need to be frugal with the number of switches used. The new Attn-2 uses two rotary switches, one 6-position switch (on the left) for fine decrements of 1dB and one 12-positon switch (on the right) for coarse 6dB decrements, which allows for 0dB to -65dB in 1dB steps for two channels.

This cleverly designed stepped attenuator exploits both the series-attenuator and the ladder-attenuator stepped-attenuator configurations to yield the best compromise between flexibility, performance, and cost. The Attn-2 attenuator uses two rotary switches and 21 resistors per channel to yield a total of 66 positions of attenuation in -1dB and -6dB decrements. Had the attenuator been entirely of a series design, the attenuator would require a two-deck 66-position rotary switch and 132 resistors; a purely ladder design, a four-deck, 4-pol, 66-position rotary switch and 260 resistors. In contrast, the Attn-2 attenuator, from 0 to -5dB of attenuation, is solely a ladder attenuator, with no more than two resistors in the signal path; thereafter, the attenuator uses both a ladder and series configurations, with never more than 12 resistors in the signal path.

The PCB is 6 by 1.9 inches and the switch spacing is 3 inches.

Kit includes two Grayhill rotary switches with hard-gold contacts and a PCB. Resistor packs are optional.