A new alpha release for the QA401 has been released to address Windows 1803 issue. Please use the Support link to get to the release.

QA401 Release 1.60

Now with Multitone. Test Gain, Frequency Response and Crosstalk in 500 mS

Recent Blog Posts

A CMOS Pre-Amp for Hi-Z sources

A CMOS Pre-Amp for Hi-Z sources

==DRAFT FOR REVIEW== A few posts back we took a look at the challenges of measuring high-Z sources with audio analyzers than have a bi-polar based ...
User Weighting and RIAA

User Weighting and RIAA

A new feature in release 1.6 allows you to specify an arbitrary user weighting to the displayed data. This came as a request from those that are us...
Input Current Noise Density

Input Current Noise Density

One of the new features in the QA401 1.6 release is the ability to display noise density. A user was curious why the noise density calculations cou...
Characterizing LDOs: Part 1

Characterizing LDOs: Part 1

LDOs might seem to be interchangeable. And in many circuits they are. But when you are chasing the last few dB of performance in a 24-bit DAC or AD...
Quick Look: A Generic TPA3255 Design

Quick Look: A Generic TPA3255 Design

This time, we purchased a TPA3255-based no-name class D amp that is commonly seen on E-bay or Amazon for around $60 or $70.
ASIO and Hypermiling THD

ASIO and Hypermiling THD

Hypermiling is the act of driving a car with extreme efficiency so as to maximize the miles per gallon achieved. It requires a careful understandin...
Swept Measurements

Swept Measurements

The QA401 software supports the ability to make swept measurements. You can even write your own measurements in DotNet (C++, C# or Visual Basic) an...
Simple Isolated +/-15V Split Rail

Simple Isolated +/-15V Split Rail

There are a lot of solutions out there for generating split +/-15V from a single DC voltage, but all are lacking in some way or another. Either the...
QA401 and USB Noise

QA401 and USB Noise

The QA401 relies on USB power. This is a great convenience because it means setup and making a measurement is quick and easy. But not all USB power...
QA401 Update 1.50

QA401 Update 1.50

We’ve had some features in the queue for a while on the QA401 that made it out in the 1.50 release. Remember, the goal with the QA401 isn’t the be-...
Ultra-low Current Measurements with the QA150

Ultra-low Current Measurements with the QA150

This post looks at how the QA101B Mixed Signal Oscilloscope and QA150 High Side Current Sense Amp can be used together to help the engineer underst...
ABX Testing and Distortion

ABX Testing and Distortion

Intro ABX testing is a way to compare two similar versions of something, in this case sound. The user is presented with an audio stream called the ...