Amanero Long Term Measurement (II)
Previously, I had tested the Amanero USB board with respect to unlocks [link]. Aiming at cleaning up some of the unlocks, I added output caps to the regulators. Now the regulators have both input and output caps.
I attached the capacitors to the small SMD output caps of the regulators.
CAUTION: this is probably not the best way to install the capacitors. I put a slight pressure on the cap to straighten it and it immediately pulled the smd cap off the solder pads. Luckily I was able to solder the smd cap back to the solder pads. If you install it this way, exercise care in handling the board. It is safer to solder the caps either vertically or tilting inwards.
Here are the results (click for larger image)
For reference, here are the results for input cap mod only:
Seems fairly the same; maybe a bit cleaner, but with one test, I think it is within the statistical variance of the measuremets.
Based on the design, this board promises very low jitter. The local regulators are already very low noise and have been used in other good implementations. Good bypass is used throughout. LC filters are also used for powering the on-board clocks. You can read more here [link].
However, there are more unlocks in this board as compared with the Musiland device. I had already implemented a series of mods in the Buffalo II DAC where together with the mods on the Musiland I was able to have zero unlocks even during a 24 hour period, thus I am confident that the unlocks observed here are primarily from the Amanero board.
We can conclude therefore that both the Amanero and Musiland devices are low jitter devices, with the Amanero having at least a design edge for lower jitter but the Musiland seems to have an edge with respect to blocking external disturbances such as noise sneaking through the power line and EMI. Even with the use of DC-DC switching converters, the Musiland seems more capable of providing a more stable environment resulting in less or no unlocks. In fact, after 9:00 AM, the numbers of unlocks for the Amanero board got worse (I suppose people are awake and there are more electrical activity in the house and neighborhood).
Both of the devices are designed to be powered through USB, the only difference is that the Musiland is a finished product and has a case and the Amanero is an OEM product and comes in the form of a bare board. Installed with the BII DAC, the Amanero resides inside a case; the Musiland resides inside its case which is inside the DAC case providig additional shielding. I don’t know if this is a factor but I will test this out at a later date. Perhaps also, the LC networks used to filter the switching regulators in the Musiland also provide additional resistance from external disturbances. The only other difference is the USB cable. The Musiland uses a generic USB3 cable and the Amanero uses a generic USB2 cable. Based on my observation, it seems the Amanero board requires additional power conditioning in order to achieve its potential.
For now, the Musiland is working better in my system.