NKP, as in Noise Killer Plug, can be plugged directly onto power header on any eurorack power distribution bus
without loosing any connection point as any euro power cable can be plugged on top of NKP.
Another option is to put NKP at module's power entry, provided it's 16-pin header. NKP efficiently
filters high frequency noise typical for systems supplied with switching supplies. It also can isolate
noisy modules, that inject a lot of noise to the power bus, or isolate sensitive module from noisy
power environment if NKP is plugged at the module. It takes just one NKP plugged to any header
of POWDIS power distribution board to clean up power dramatically for all modules connected.
This is due to low impedance of all the buses in POWDIS. Putting 2 or more NKPs in various
headers further improves ripple rejection, especially at higher frequencies. If used with other power
distribution boards it may be required to put more NKPs, as there are many bus-boards with thin,
narrow traces exhibiting higher resistance and ripple rejection over big number of headers is
difficult. And for flying bus-boards it's best to put one NKP in every socket.
Here are example screen-shots from initial testing. All measurements are normalized to 0dB, which
compensates non-perfect characteristics of testing environment, which in this case was pretty
good, showing +/-1dB flatness within 1GHz bandwidth.
Wide overall view, 800MHz bandwidth. It's clearly visible that it works best up to about 200MHz,
but still provides 15 to 25dB attenuation above that
A little closeup of lower band, with nearly 41dB attenuation at 30MHz
Here we can see lowest 3MHz, where the highest attenuation happens
And the lowest part of the spectrum, up to 300kHz
Here are some scope-shots, only as an indication of NKP influence on power bus. Left screen
shows +12V bus measured at one of the pin headers of POWDIS power distribution board
supplied from small (35W) MeanWell switching supply, at 1A load. Right screen shows the same
setup, but with NKP plugged to the adjacent header of POWDIS:
Same settings in both screens, 5ms/div and 20mV/div
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