If you are unfamiliar with audio measurements please use a search engine with the query: "audio measurements" or "audio measurement handbook" Look for publications by Richard C. Cabot and also by Bob Metzler, both from Audio Precision. There are other useful publications as well. These will provide basic knowledge. Interpretation of the following measurements is beyond the scope of this post. mcth 28V LPS and SMPS technical measurements mcth = Massdrop Cavalli Tube Hybrid headphone amplifier SMPS = Switch Mode Power Supply LPS = Linear Power Supply The data presented were acquired using the following equipment Power Supply only measurements 1. picoscope 5243B, Keysight 34461A DMM 2. 56 ohm 50W load used for power supply measurements 3. Cable Matters 16 awg cable for 28V connections 4. Shielded 14AWG and 16AWG power cables 5. Vaunix Lab Brick USB hub for measurement equipment 6. Audioquest Forest and Schiit Pyst USB cables used for measurement equipment MCTH measurements with LPS and SMPS additional equipment 1. PrismSound dScope III 2. Massdrop Cavalli Hybrid Tube headphone amp 3. Electro Harmonix 6922 driver tube 4. 30 ohm load used for headphone amp measurements 5. Unbalanced cables Worlds Best Cable Gotham GAC-2 RCA with mcth 7. Amplifier gain adjusted to 0 dB gain @ 0.775 Vrms 0 dBu 8. MCTH gain knob at approximately 1:30 to achieve 0 dB gain Power Supplies tested 1. SMPS 1 mcth XY36S-2801250Q-UW 28Vdc 1.25A 35W max 2. SMPS 2 Meanwell GST25A28-P1J 28Vdc 0.89A 25W max 3. LPS 1 Keysight (HP/Agilent) U8001A 0 to 30Vdc variable 3A lab supply 4. LPS 2 BK Precision 1627A 0 to 30Vdc variable 3A lab supply 5. LPS 3 Acopian A28MT210 28V 2.1A low noise linear power supply Yet to arrive - still in transit 6. LPS 4 ebay Finished 65VA Ultra Low Noise Linear Power Supply Presented is a comparison of 5 power supplies, their noise and respective effect on specific mcth audio measurements. Notable highlights: mcth measurements improve with lower noise linear power supplies. Subjectively my auditory experiences concur, to my ears. Using an RME ADI-2 Pro, Soekris dac1421, Yggdrasil v2, etc. with any of the three LPS enables an extraordinary blackground from which music appears. Setup picture: Ripple measurements Ripple 28V 56R load 20mV/div 5mS/div 100KHz - mcth SMPS Ripple 28V 56R load 20mV/div 20uS/div 100KHz - mcth SMPS Ripple 28V 56R load 20mV/div 5mS/div 100KHz - Meanwell SMPS Ripple 28V 56R load 20mV/div 20uS/div 100KHz - Meanwell SMPS Ripple 28V 56R load 20mV/div 5mS/div 100KHz - Keysight U8001A Ripple 28V 56R load 20mV/div 5mS/div 100KHz - BK Precision 1627A Ripple 28V 56R load 20mV/div 5mS /div 100KHz - Acopian A28MT210 Ripple is considerably lower with all three LPS than either SMPS. Data is not presented on the Noise Nuke. While stable with a purely resistive load, neither SMPS was able to stabilize output voltage with the combined Noise Nuke and mcth reactive load. Therefore use of the Noise Nuke is NOT RECOMMENDED.