Recent Blog Posts

Characterizing LDO Noise: Part 3

Characterizing LDO Noise: Part 3

In Part 2 of the examination of LDO noise, we ran into the limits of the QA401 while evaluating the output noise of the LT3042. And this shouldn't ...
QA401H, REST and Python

QA401H, REST and Python

Release 0.94 of QA401H is up at Github. Release 0.94 moves a step closer to shipping the headless version of the QA401 control software, and measur...
Characterizing LDO Noise: Part 2

Characterizing LDO Noise: Part 2

Previously we used the QA350 microvolt DVM to look at the standard deviation of different types of LDOs. That measurement helped us understand the ...
Automated Amplifier Testing with Tractor

Automated Amplifier Testing with Tractor

We previously went through a quick characterization of a tube guitar amplifier in the blog post located here, with a promise that we’d come back an...
Release 1.726 Graph Types

Release 1.726 Graph Types

The graphing plug-ins have been re-named and re-organized for 1.726. This post will highlight the types of graphs than can be created. Until the do...
TI TPA3255 EVM

TI TPA3255 EVM

Later this week 1.726 will release, with a lot of changes to plug-ins and graphing of stepped tests. The aim over the last month has been to dramat...
Fast Tube Amp Characterization

Fast Tube Amp Characterization

A look at how to quickly characterize a low-cost, 5W guitar amplifier.  And in case you missed it previously, a video looking at automation and me...
Rapid USB DAC Evaluation

Rapid USB DAC Evaluation

DACs--the standalone kind and not the integrated-circuit kind--have been part of home systems for more than a decade now. They can pose a bit of a ...
Quantifying Fuzz

Quantifying Fuzz

In release 1.709 for the QA401, the ability to graph distortion versus level for a given frequency was added. This is achieved using the new Test P...
OPA2156: HiFi in CMOS

OPA2156: HiFi in CMOS

The OPA2156 is a new, high-performance op-amp from TI. Normally, that's not newsworthy because higher performing parts are coming out all the time....
ASIO Arrives

ASIO Arrives

ASIO401 is an open-source ASIO driver for the QA401 created by Etienne Dechamps. Aside from some input I had on how the QA401 wire protocols operat...
Low-Cost Test Setups

Low-Cost Test Setups

A common question we get is "Can I run the QA401 on an older machine?" In general, as long as the PC is running Windows 10 the answer is "yes." The...