Possibly very stupid question.

[john.hostetter]

So I just completed an "Improved Hum Free A/B/Y" and it works great! I'm so proud...

Two questions:
-I noticed that when I have a battery in, I cannot get the LEDS to turn off. I can turn one off, but at least one is always slowly draining my battery. Is this something I can solve by modifying the LED circuit? Do I need to put in an on/off switch?

-The circuit didn't work for me until I fooled around a little with the components. I noticed on the circuit board and in the bill of materials the project calls for a 2N3906 transistor. I didn't see this included in the schematic. Just out of curiosity, what does this component accomplish? Is it necessary?

Thanks!

[PRR]

Possibly very stupid question, but.... what plan did you use?

The one at http://www.geofex.com/FX_images/humfree2.gif shows a power switch. (Also two batteries.) The signal passes through the chip (triangles). When you turn it off no signal will get through. And interestingly the "off" LED still has battery-drain; he just diverts current from the LED (possibly to reduce click).

The version at http://www.geofex.com/FX_images/spltr2.gif is quite different, does not pass current around "off" LEDs, and says "power switching not shown".

And the "Hum Free Signal Splitter" shows a clever 3-transistor power switching scheme.

It's not a power-hungry box, but you do want to turn it off or remove the batteries when done playing.

You can build a no-battery A/B/Y switch. But there are real benefits to these buffer chips, and some convenience in the LEDs. What does it cost to run, maybe a dime an hour? That's less than your beverage cost.