Blog Entries

NAMM 2019

NAMM 2019

NAMM is the premiere event for those that manufacture musical instruments and accessories to connect with buyers--from independent music shop owner...
Estimating Circuit Yields

Estimating Circuit Yields

A common exercise for all design engineers is understanding the "spreads" or yields on their circuit performance. When using SPICE, this can be don...
QA401 Headless & Linux Support

QA401 Headless & Linux Support

There are two recurring requests for the QA401 platform: First, people ask if they can easily control the hardware from a language like Python, Mat...
QA401 Release 1.70

QA401 Release 1.70

Release 1.70 should be out this week and adds in a test plugin (Test Plugins-> Speaker Impedance) that makes it easy to measure the impedance of...
Tractor: First Look

Tractor: First Look

Tractor is a framework for driving automated testing. The first focus is on amplifier testing using both the QA401 Audio Analyzer  and the QA450 Pr...
QA450 Programmable 8/4 Ohm Load

QA450 Programmable 8/4 Ohm Load

If you are designing and shipping high-powered amps and looking for an economical testing solution, we are putting the pieces in place to deliver what you need. Combined with our QA401 audio analyzer, the QA401 and QA450 working together will facilitate inexpensive, rapid testing of a range of amp power levels and topologies. 
QA350 gets True RMS

QA350 gets True RMS

The QA350 thus far has been a high-resolution DC volt meter, with a bandwidth of 1.1 Hz (slow sampling) or 441 Hz (fast sampling). Release 1.70 cha...
A CMOS Pre-Amp for Hi-Z sources

A CMOS Pre-Amp for Hi-Z sources

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 front-end. The big tr...
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

Part 2 of this article is located here. LDOs might seem to be interchangeable. And in many circuits they are. But when you are chasing the last fe...
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.