No signal from right input channel

1

Hello,

I’ve been evaluating the QA403 for testing on both a Windows 11 and Ubuntu 24.04 machine and had no issues working through the Quick Start examples and using the REST interface to get measurements from the unit.

Randomly, the unit’s right input channel no longer reports any signal. When I run the simple example from the REST API (Default Settings, Gen 1 at 1 kHz, 0.00 dBV, 32K buffer size, python with requests lib), I get ThdDb: NaN and PeakHz: 0 for the right channel. With the same script, I get ThdDb: -80.6688750597207 and PeakHz: 1000.48828125 for the left input channel. This behavior is consistent whether the +/- L or R output channel is used, and between Windows and Ubuntu. Nothing is shown when using the Audio Analyzer software.

I have the unit powered by a USB Hub capable of 20W which reads 5.0V on the USB power rails with a DVM, but the unit reports ~4.70V USB Voltage and ~1.45A USB Current.

I have tried various high quality (and short) USB cables, and am using a known good BNC cable for the loopback testing.

Software Version: 1.220, Firmware Version: 60

Any help or recommendations on troubleshooting are much appreciated.

Thanks,

Evan

2

Hi @kabae, I think you are going to need to send this in. The 1.45A of current shouldn’t be happening. Can you contact the sales support at quantasylum dot com alias and we can get this sorted.

Thanks, Matt