Footswitch / Channel Switching circuit question. What have i done wrong?

[ACHIEVEIT]

Hello guys,

i am having trouble with the Footswitch I am using when switching channels in my latest build. You can see the circuit of the channel switching and the footswitch below.



As can be seen, I am using a bridge rectifier on the 6v3 heaters (the heater winding of the PT can supply more than enough current for the heaters + the channel switching circuit easily). The circuit is floating - i have not used the ground of the amp (chassis) as a reference point - otherwise I wouldn't be able to obtain the voltage needed for the relay. Then, after the filter cap, you can see that there is the relay (with its accompanying diode) and in parallel there is the panel led with its resistor. The circuit is then connected to the switched jack and as can be seen, if no footswitch plug is connected, the panel switch dictates the channel switching, while if a footswitch is connected, the panel switch is ignored. The circuit inside the Footswitch housing that I have implemented can be seen on the lower-right (Tip -> Resistor -> Led -> Switch -> Sleeve)

The problem is this: if I connect the aforementioned Footswitch (with the Led), then the relay is not switching (and the panel LED not working) but the Led of the footswitch operates normally (switches on and off by pressing the footswitch). If I connect a simple footswitch with no Led (so just a SPST switch), everything operates normally!

It is my understanding that this indicates a voltage or current problem but I cannot wrap my head around this one. It might be easy but I am stuck and don't seem to understand why this is happening.

So, although I was pretty certain about my calculations, I went ahead and measured the voltage after the filter cap and sure enough it is as expected ~7v5. That should be enough to accommodate for the voltage drop of the Relay AND the Footswitch LED.

What am I missing??

[Jazz P Bass]

The footswitch circuit has too much of a voltage drop to operate the relay.
Maybe use a double pole switch.
Separate the circuits.

[ACHIEVEIT]

Nevermind guys, I found it. Writing down the whole thing actually helped me realize a few things. I have attached the working schematic for reference in case someone faces the same problem.



My train of thought was this: the relay drops 5v and needs 30mA to operated. The panel led drops ~2v2. So the resistor of that led has a voltage drop of 5-2v2=2v8. With its resistance 470R, the current that passes through it and the led is ~6mA. So the combined current that goes to the footswitch is ~36mA. That is a little too much for a single led and this is why I added the resistor in parallel. Since the f/t led drops almost all of the remaining voltage (7v5 - 5 = 2v5), the value of that resistor if we want it to pass ~20mA through it should be ~200ohm. I tested the circuit and it works now. It was somewhat obvious but anyway. Thanks for reading!