RG's A/B/Y from GGG- really dim LED's and slight hum

[theundeadelvis]

I built RG's A/B/Y box from GGG and it works, but I have one snag. When I stomp the switch for either output the LED is slow to illuminate and when it does it is very dim. When both are active I don't think they are lit at all. The interesting thing is if I step on the A or B switch and hold it down the LED lights very brightly. I'm pretty baffled on this one. I subbed no parts and used the MAX1044CPA ic. I did initially wire the switches wrong so I hoping I didn't damage something. There is also a hum but I'm hoping whatever fixes the led problem will fix this as well. As usual thanks much in advance!

[theundeadelvis]

Could this be a tranny problem? Could I have fried it with improperly wiring the switches?

[theundeadelvis]

One thing I don't understand on the GGG layout is that the leds aren't connected to ground anywhere? Am I missing something or is this something to with the isolation?

http://www.generalguitargadgets.com/pdf/ggg_amp_aby.pdf

[bryantabuteau]

check this out.  might help.

http://www.elixant.com/~stompbox/smfforum/index.php?topic=41462.0

[theundeadelvis]

Thank you! I searched but missed that one some how.

[bryantabuteau]

yeah, I remember reading it, and it even took me a while to find it.  Always had that problem searching for ABY (A/B/Y) etc...

[theundeadelvis]

I grounded the LEDs and they work fine now, BUT now there is a lot of hum!

I found this but I on't really understand how to implement it:
 
What you get out of any charge pump converter is DC with some AC whine on it. To filter it, you use some series impedance and some shunt capacitance. The series impedance could be a resistor or an inductor. Low resistances (10-100 ohms) often work if you use big capacitances. Inductors are even better because their resistance is low and their impedance just keeps getting bigger as frequency goes up.

Try 47 ohms and 470uF as filters. Note that you have to filter *both* the +9V and -9V because the pulses are sucked out of +9V to make the -9V. You also have to arrange things so that the signal ground connection is made right at the output of the converter and NOT on any portion of the black wire that goes back to the battery, because that introduces the voltage caused by the resistance of the battery wire into the signal ground.

[theundeadelvis]

OK here is one more piece of the puzzle. I hooked my BOSS DD-6 delay after the A/B/Y both outputs of the splitter into both inputs of the DD-6 it is completely quite. Also, without the DD-6 the hum isn't that bad with the gain on my amp down. With the gain turned up it hums prop plane.

[tennisdude]

i have a very similar thread going on right now. I had the same problem with the LED's too 

gl with yours. My hum isn't so bad, but its just enough to be a bit annoying.

john

[KMS]

Try connecting the 0V to the metal box in just one spot.  That's what it took for my A/B/Y; however; I do all my switching in my mixer not in the A/B/Y so all the channels are always on.  Not sure if that makes a difference but maybe it does.

[theundeadelvis]

I'm sure this is real basic but I am not familiar with 0V?

[KMS]

It is the ground.

[theundeadelvis]

Ahh, I thought that might be the case. Thanks!