L-pad question

[Barry H]

Hello all,
When i cleaning my l-pads in my N7000 crossovers, i put a ohmmeter across the HF outputs and found a difference between the two. When rotating one, the readings range from .5 ohms to 32 ohms when rotated clockwise. Rotating the other one, the readings range from .5 ohms to 4 ohms at midway, then back down to .5 ohms when rotated clockwise. Should they not be the same and which one is correct?

Thanks, Barry

[Baron030]

Let’s see. This is a bit of a head scratcher. If you are measuring the resistance from the two HF output terminals (E3 & E4), and rotating the L-Pad knob. At the maximum L-Pad setting, the resistance would be very low because there would be current flowing through the L2 coil. And at the minimum L-Pad setting, the L-Pad shunt resistance would be very low. So, the resistance would actually be higher at the mid point setting. In any case both networks should behave in the same way. So, one network must have gotten wired wrong or there is a wire that has come loose from the L2 coil. In looking at schematic, it would appear that the center lug on the L-Pad should be wired to the E4 output terminal. So, I would start looking with the ".5 ohms to 32 ohms when rotated clockwise" network first. That’s my best guess for now.

N7000 Network Schematic Link:
http://www.jblproservice.com/pdf/Network%20Schematics/N7000.pdf

Baron030

[Barry H]

Thanks for the tip Baron 030. It was a loose L2 coil wire in the .5 ohm to 32 ohm x-over. Now i get the same readings in both crossovers.

Thanks again, Barry