Plixir Elite BDC MK2 linear power supply – Single and Dual – 5 Volts

Measurements and conclusion

We tested both the single and dual versions for stability and noise. Jitter and phase noise was tested with the single version.

Measurements were made with a Tekbox LISN, Picoscope 5000 series scope and a variable resistor to put a load on the power supply. Stability was measured with a Rigol Electronic load. We measured up to 3A.

Jitter and phase noise was measured using an Aeroflex PN9000 with a 100 MHz Axtal OCXO as a reference. Measurements were made both with the power supply on a Dlink 108 V4 switch and on the Volumio Primo itself. In all cases, measurements were made with an active probe on the 100 MHz crystal in the Volumio Primo.

Stability and noise

Let’s start by reporting that the single-output is more stable than the dual. And then we loaded both power supplies up to 3A. The dual should be able to handle up to 5A. It will, but the question is with how much voltage drop.

We also see with the dual that if we load both outputs, the noise increases a bit on the DC output. The noise on the dual output is higher than on the single output. What exactly causes that is the question of course; probably pickup from the extra cabling, extra capacitor. We also have to do some guessing here.

Now both power supplies perform just fine in this test, but our preference is really for a single output. So if you have the budget: invest in two separate power supplies for optimal performance.

Influence on jitter and phase noise

We used the single-output for this measurement. It is clear that the Plixir scores excellently here ánd that it definitely makes sense to invest in a good power supply for both a switch and a streamer like the Volumio Primo. We see a better Allan Variance and more than 1ps jitter reduction. Phase noise at 10Hz is 5dB lower. At 1K 20dB.

We’ve written about this before – and we’ve also made an AlphaLabs video about it – and once again it shows that it really pays to invest in a good power supply.