Lumin U2 mini vs Mac laptop sound test

@johnah5 

What I find interesting is that you didn’t mention having to adjust volume when switching between USB and AES during your test. Do you remember having to make adjustments to match the differences in output levels or is just that there weren’t any differences?

I also have a Lumin U2 Mini which is output via AES into an Aqua La Scala Optologic dac. While I haven’t compared the differences between my MacBook Pro and the Lumin while streaming the same service I do know there is a huge difference when using the Lumin to stream local files (NAS) as opposed to playing local files directly through the dac via SPDIF.

Honestly I’m with you when it comes to the value considerations of Uber expensive streamers. As I only stream for auditioning music to purchase I find the Lumin U2 Mini to be a very good device. I previously had used a Sonos Connect and the Lumin definitely provided a few steps up in sound quality. While I have no explanations for the results of your comparison I wouldn’t be bummed out about the purchase.

@johnah5 

I was thinking about this a little more after reading your latest posts and I’m wondering if a change in how these “streams” are attenuated might help in discerning any differences between the devices you’re using.

You mentioned before that you were controlling volume from within the Tidal app. This seems counterintuitive to me as I’ve always adjusted volume within software to its maximum and used my preamp to attenuate the final output.

In reading through the manual of your dac/pre I also noticed there are dip switches that allow you to set the “Director” to Unity Gain. I would suggest trying this setting if you find it more convenient to use the volume control within Tidal. The problem with this is that you’re completely relying on the software/circuits of your Mac Air for processing the volume into the Director (via USB). In the case of the Lumin you’ll be balancing the output between its internal LEEDH processing and the values dictated within the Tidal app.

For me- I would prefer using the Director as it was designed to be used allowing the AKM chip and the preamp to control all. That should take away any variables seen between software/hardware. I would recommend trying the following setups for your listening tests (hopefully I understand the signal chain enough to not introduce other problems).

SPL Director- Leave the dip switches on RCA/XLR in the OFF position so that the Director controls the volume output.

Mac Air- within the Tidal app set the volume to 100%. In system settings select your USB output to see the Director as the device and set the volume to 0.0 dB (100%). Connect via USB to the Director.

Lumin U2 Mini- Connect the Lumin to the Director via AES. Within the Lumin configuration settings adjust the volume control to 100% and within the LEEDH tab select OFF. Adjust all of your upsampling modes to the native rates supported by the AKM chip within the Director (see manual). 
With these settings the volume of Tidal may vary when switching inputs from AES to USB- this is a “tell” that demonstrates the attenuation differences between devices. You should be able to level match each fairly well with a dB meter app. If your Director holds the volume level from each input while switching you can quickly match the levels and get back to comparing each device/signal path on its own merit.