by EWBrown » Fri Mar 13, 2009 6:07 am
With these particular Hammond trannies and chokes, the center axis of the windings is in the same plane as the long axis of the labels on top.
In your first photo, there is magnetic coupling between the choke and the OPT and in the second, coupling betwen the power trannie and choke (which is a lesser problem). The leads on the choke could be swapped in order to buck the magnetic field from the power trannie.
Think of X axis as left and right, Y axis as front and back, and Z axis as up and down.
If you could lay the power trannie on its side, then picture 2 would be the ideal "XYZ" orientation.
The ideal situation is like an ST-70, that the axes of the windings of the power trannie, outputs and choke are all at mutually perpeidicular axes (X, Y, Z) . FWIW, the core orientation in most open freme trannies and chokes (like the C354) is vertical.
The best solution, if the chassis dimensions allow, would be to locate the power trannie and choke at one end of the chassis, the board in the center, and the output trannie at the other end. This allows more separation, and makes the wiring from the iron to the board more direct, with a cleaner under the chassis layout.
HTH
/ed B
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