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U-pad and L pad for high-end resistors at line level

These are U-pads (balanced) that can also be configured as L-pads (single ended) for fixed attenuation at line level. They are designed for use with large high end resistors. Both boards accept 1.2 mm leads. In simplest terms, it is a DIY fixed level passive volume control.

The search for higher and higher fidelity leads many to a complex system. Bi-amping, tri-amping or beyond is usually the approach of such a system. It allows each individual driver or section of drivers to complement an amp right where that amp shines the most. Since the amps used are usually quite different in specs the trick is to then match the gain of each amp. There are a few ways around this already. These boards are for those who do not use DSP or would like to take a volume pot out of the signal chain for fixed level matching. They are also an inexpensive way of getting into using high-end resistors for volume control.

V.1 has a single resistor for R2 giving an average of 1/4 dBv stepped attenuation which may be all that is needed. V.3 allows 2 or 3 resistors in R2 giving exact attenuation control. Both boards are made with the same .093" thick FR4 with 2 oz. extra wide copper tracks, lead free HASL finish and are made in the USA. They come with (4) Phoenix Contact terminal blocks.

STUDIOPHON

V1 Example: U-PAD configuration with Audio Note Tantalum 2W resistors in R1 and Audio Note Tantalum 2W in R2 position
V3 Example: U-PAD configuration with Audio Note Tantalum 2W resistors in R1 and Dale / Vishay in R2 position
 

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