USB Conditioner and Power Injector

Production will resume when some components become available.

2 Channel Limpio

1 Channel Limpio Light Edition

Back Panel View

Internal View

Internal View, Main Board (w/o the Main Module)

Internal Main Module

Range Extender


This device is designed to clean USB High Speed  signal from a source (PC, media player, etc.), provide clean 5V DC power from a linear power supply to an audio end equipment (DAC).

There are 3 main problems when using the USB interface for an audio DAC:

Limpio, The Cleaner

To solve the 1st problem, we use a high-speed USB 2.0 signal converter (re-driver) to compensate for both AC losses (due to capacitive loading) and DC losses (due to resistive losses) in transmission channel. 

The purpose is to re-store the signal integrity of a USB High-speed channel up to the USB connector. The loss in signal quality stems from reduced channel bandwidth due to high wire losses and other components that contribute a capacitive load. This can cause the channel to fail the USB near end eye mask.

With edge amplifier, it increases static levels with DC boost function. In addition, it includes a pre-alignment feature to improve receiver sensitivity and compensate for intersymbol interference (ISI) jitter in applications with longer cable lengths. 

This improves signal quality without changing the packet timing or adding propagation delay or latency and also helps the system to transfer USB 2.0 high speed near end lug to cable matching while 5 meters. Also cable length up to 10 m using an extension cord.

To solve the 2nd problem we use two things:

The 3rd problem is solved by the same methods that solved the previous two:

An optional Extender Unit can be used to further increase the length of the input cable.  This extender is the same signal converter as used in Limpio, but in the small separate  case.

Depending on the quality of the cable, we got 12m total length between the PC and our USB powered ATDAC-8AX.

The extender can be used without Limpio. In this case, it is supposed to solve only the 1st and partially the 3rd problem (see above).


In addition to its features, Limpio (full version) has two inputs. That allows you to connect one DAC to two sources (f.e. PC and TV).

Each input has a separate galvanic isolation and a cleaner, which significantly increases the cost of the device. Therefore, in addition to the full one, there is a Lite Edition version of Limpio-LE with only one input.

Since some DACs are designed to be connected with two cables (one for power only, the other for data), the Limpio has an additional USB-A output connector, which has power only. The main output connector contains both data and power.

Depending on the switch on the rear panel, the DAC can be powered either continuously or only when there is input voltage on one of the USB input connectors.

With the "on" button, the power to the DAC can be turned off in any of these options. In the off state, the device consumes meager power, and the switch on the rear panel can be completely disconnected from the outlet.

 Limpio Block Diagram