|E_Notes : Page #1.00
A collection of notes that I am collecting usually relating to audio or electronics. Comments are wellcome.
Also found on the fabrication page.
These are screen captures of some of 6 pages of notes I put together to put some kind of handle
on filament current and the potential hum from the flux.
This is my first attempt at a web site. So things,
will no doubt be, dynamic for a while. Change is
the only constant.
|Listed below are some notes I have collected including :
Hum I wonder from, where it Come ?
Joule 1/100 of one droplet of beer.
|WMF of schematic above.
Above is the schematic of a TDK KU-33394V-OT
This version creates 3 negative DC supply
voltages, -10V, -15V, -20V, plus a center taped
The schematic shows a modification I did to get
|I purchased these little supplies at :
First 25 at 2 for a buck then 200 more for $0.25 each. Hard to find raw transformers
for a quarter each.
These are conventional mode high frequency, (about 120kHz), DC to AC to DC
power supplies. The transformers work in pulse mode. I hooked a PWM controller
and MOS switch to one of the transformers and got several hundred volts pk-pk.
|Ground Loop / Looping
|For a single ended supply :
Input is the difference between, Vref and Source.
|Vref can ride on top of Vg. In this case Vg is proportional to the signal in that part of the circuit.
The effect of Vg on Vref is basically masked in this case.
|In this case Vg of unrelated circuit stages can cause voltage drops across
other module's ground path resistances.
Thus modulating the Vref with the voltage drop of the unrelated signal.
Modulating ground is the same as modulating the signal in the context of single ended designs.
|Ground or Vref Modulation