The hardest project (and the longest) Allo has designed. It took 2 years...
Nirvana SMPS was designed to power audio devices with the lowest noise.
There are 3 types of noise:
1. Differential noise (noise on power lines compared to GND)
This is what everyone calls noise. This it the easiest to understand, and where Nirvana first shines. 0-20Khz (audio band) noise is 0.4 to 1.2uV including mains frequency. Please note that those numbers reflect real world testing with no isolation transformers (since you don’t have one in your house).
2. Common mode noise
A bit harder to understand, it represents noise on both power and GND that moves in the same time. Since GND has the same noise as power lines, it's invisible to most test equipment (single ended probes). Nirvana shines again at filtering common mode noise, with less than 1uV 0 to 20Khz.
3. Leakage current
Any switched mode power supply (smps) has a small transformer that creates EMI because of the abrupt on/off of mosfets. To counter it, there is a capacitor across the input and output of the transformer (that has a special rating Y since failure can be catastrophic). The problem is that EMI filters (AC side) is leaking some current that finds its way to the Y capacitor and into GND of DC side. There is, however, a simple solution: earth the AC side first (Nirvana does this) and if needed earth the DC side ground. Nirvana has a switch that allows both to have the 5V side ground earthed or floating.
Those are the main noises on output... but wait, that’s not all. The SMPS makes noise that finds its way into AC (where your DAC and AMP take power). Nirvana uses a rather sophisticated network of EMI filters (common mode) and inductors (differential noise) protection for the AC side, in addition to DC side.
At last. with all the noises down, Allo looked at one more parameter that makes sensitive devices perform better: capacitors. With plenty of power on the output of SMPS, you smooth all abrupt current demands. Nirvana has 8200uF of capacitors (chosen to have good thermal rating) that’s usually 10x more than what you find on a normal SMPS.
All this to say that Nirvana SMPS is a true competitor to a good LPS. It do not compete on marketing, but on good engineering.
Nirvana has only one output at 2.85A/5V
No load is 5.2V , 2.85A 4.97 to 5.03V
The provided USB connection is for convenience only, it’s not a second, galvanically separated output.
PS: Allo often get asked, what’s better, Nirvana or Shanti. Well Nirvana is a small SMPS vs a big LPS. Cheaper to ship. Shanti is slightly better to the ears, but it depends on how good your system is.
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