Bluetooth Amp Testing

I thought I’d give the Open Loop Acquisition a go on a Cambridge Audio A5 amplifier where I’d added an Arylic Wifi Audio Receiver Up2stream Mini V3. The wifi and BT module is mounted on a daughter board located where a phono stage is usually fitted and provides the necessary 5v at 1A power and audio connectivity:

Initially I was getting sporadic results even after adding a 2 second silence to the beginning of the QA generated chirp track. The workaround I used in the end that generally resulted in a decent spectrum was to add a couple of seconds of noise. This seemed to work most but not all of the time:

As you can see the Arylic streamer gives a good flat response, although there is an unexpected 16.5kHz filter. I’m not getting excited by the 0.75dB difference between left and right which can probably be fixed using their ACP workbench software:

Thought this may be a helpful tip.

I’ll play around some more to find out what this particular module needs to avoid the noise gate problems.