What's the easiest method to add an LED to a dpdt switch?
I am using a dpdt as 3pdt are not available where i live.

I heard about the millenium bypass but it's very complicated. I want something simple even if it's not gonna be true bypass (or maybe if someone know a simple way to achieve that with true bypass)

I found this image online but i don't understand the left side and idk if it's gonna work



Thank you

Quote from: antonis on October 25, 2024, 07:46:54 AM

Excuse me but I don't understand this part circled.


Also if i wanted to make this little circuit with an arrow on a small piece of veroboard. How can that be excuted?

It's a p-n-p BJT..
When Effect is ON, BJT is OFF(Base open - not working) and LED is ON (V+ -> 10k -> LED -> GND)
//      //      // OFF    //  // ON (Base grounded via VOL pot wiper / lug1) and LED is OFF (BJT is saturated, hence Emitter voltage lower than LED's forward voltage drop)
The necessity of "some resistance" is due to Q1 Base current limitation need..  


P.S.
To be honest, I never used Jack's configuration 

Joe Davisson's one worked perfectly in a couple of cases..
(indicator for clipping diodes and tonestack on-bypass..)

Quote from: antonis on October 25, 2024, 08:36:37 AMIt's a p-n-p BJT..
When Effect is ON, BJT is OFF(Base open - not working) and LED is ON (V+ -> 10k -> LED -> GND)
//      //      // OFF    //  // ON (Base grounded via VOL pot wiper / lug1) and LED is OFF (BJT is saturated, hence Emitter voltage lower than LED's forward voltage drop)
The necessity of "some resistance" is due to Q1 Base current limitation need..  


P.S.
To be honest, I never used Jack's configuration 

Joe Davisson's one worked perfectly in a couple of cases..
(indicator for clipping diodes and tonestack on-bypass..)

I am sorry man but i am just still a beginner and don't understand most of this.
The schematic in the top left of the image you sent, would that work?



Like if i made this on a daughter veroboard and connected the row of the base to the pin on the switch it should connect to, would that work?
Or is my veroboard layout wrong?

Wrong. It's E to resistor, resistor to 9V (remember, it's a pnp transistor, so emitter is high and collector is low).

Then the LED "bridges" E and C (anode to E, cathode to C). B to switch, C (and LED cathode) to ground.

On a Veroboard:

track 1: 9V, one end of the resistor
track 2: other end of the resistor, E, LED anode
track 3: B
track 4: C, LED cathode, GND

I highly recommend the millenium circuit. it can be reduced to just the mosfet and gate diode, along with the led and clr, and still work perfectly well.

Quote from: Lost_soul on October 25, 2024, 07:30:52 AMI heard about the millenium bypass but it's very complicated. I want something simple even if it's not gonna be true bypass (or maybe if someone know a simple way to achieve that with true bypass)

I encourage you to stretch your mental muscles. If you have not already, read the original Millenium Bypass articles at geofex.com - don't just hear about them somewhere on the internet.

Although the Millenium may appear complicated, it's really not. The essence is really just the two component as duck says - a diode and a MOSFET.

The diode leaks nanoamperes into the gate of the MOSFET, which turns on and in turn switches on the LED through its resistor. It does this all the time - unless something pulls the gate of the MOSFET down by shorting those diode-nanoamperes to ground.

The effect is set up with a resistance to ground on its output. This resistance is usually already there in the form of a pull-down resistor to prevent switching pops and clicks. Most effects have these. The effect output is arranged to connect to either the output jack or to the gate of the MOSFET.

When the effect is on, the effect output is switched to the output jack, and sound goes through. The gate of the MOSFET is connected only to the diode, and turns the LED on.

When the effect is switched off, the effect output is switched to the gate of the MOSFET, and this pulls the gate of the MOSFET to ground, turning off the LED.

Quote from: R.G. on October 25, 2024, 10:33:23 AM

Quote from: Lost_soul on October 25, 2024, 07:30:52 AMI heard about the millenium bypass but it's very complicated. I want something simple even if it's not gonna be true bypass (or maybe if someone know a simple way to achieve that with true bypass)

I encourage you to stretch your mental muscles. If you have not already, read the original Millenium Bypass articles at geofex.com - don't just hear about them somewhere on the internet.

Although the Millenium may appear complicated, it's really not. The essence is really just the two component as duck says - a diode and a MOSFET.

The diode leaks nanoamperes into the gate of the MOSFET, which turns on and in turn switches on the LED through its resistor. It does this all the time - unless something pulls the gate of the MOSFET down by shorting those diode-nanoamperes to ground.

The effect is set up with a resistance to ground on its output. This resistance is usually already there in the form of a pull-down resistor to prevent switching pops and clicks. Most effects have these. The effect output is arranged to connect to either the output jack or to the gate of the MOSFET.

When the effect is on, the effect output is switched to the output jack, and sound goes through. The gate of the MOSFET is connected only to the diode, and turns the LED on.

When the effect is switched off, the effect output is switched to the gate of the MOSFET, and this pulls the gate of the MOSFET to ground, turning off the LED.

Thank you R.G
i followed what you said and i looked at the millenial bypass and found it to be not complicated as i thought it would

i tried adding it to my first vero build of a zvex SHO but i failed. no sound when effect is on and the LED doesn't turn on at all.

i will make a new post about issues i am having and would love if you could give me a helping hands

If you make up just the MOSFET, diode, resistor and LED, you can test the operation of the indicator part by simply touching a resistor of, say, 100K or less, between ground and the MOSFET gate. This will turn the MOSFET and LED on and off all by itself. Once you know it's working, you can just wire that connection into the switching.

The Millenium Bypass is a sensitive detector of whether the gate of the MOSFET is open or has some resistance to ground. The switching part is just a sneaky way of getting true bypass while connecting the output resistance of the effect to the MOSFET gate to turn the LED on and off.

Be very careful to look up the pin out of the MOSFET you use and connect it correctly.

But what is the real advantage of the Millennium bypass these days? Back then, 3PDT may have cost a fortune, these days not so much.

Quote from: fryingpan on October 27, 2024, 03:33:00 PMBut what is the real advantage of the Millennium bypass these days? Back then, 3PDT may have cost a fortune, these days not so much.

As the OP says in his first post: "I am using a dpdt as 3pdt are not available where i live." He can't get a 3PDT easily.

As to general utility, yes, in the 24 years since the Millenium came out, 3PDTs have become a simple-to-wire choice that is reasonably priced. There are two situations where the Millenium still plays. One is when, like the poster here, you can't get a 3PDT; the other is when for some reason changing a DPDT to a 3PDT in an existing effect isn't practical, and there is space to fit in a diode and a MOSFET. In those situations, the Millenium can have a real advantage.

Quote from: R.G. on October 27, 2024, 03:12:22 PMIf you make up just the MOSFET, diode, resistor and LED, you can test the operation of the indicator part by simply touching a resistor of, say, 100K or less, between ground and the MOSFET gate. This will turn the MOSFET and LED on and off all by itself. Once you know it's working, you can just wire that connection into the switching.

The Millenium Bypass is a sensitive detector of whether the gate of the MOSFET is open or has some resistance to ground. The switching part is just a sneaky way of getting true bypass while connecting the output resistance of the effect to the MOSFET gate to turn the LED on and off.

Be very careful to look up the pin out of the MOSFET you use and connect it correctly.

Should i do that test while connecting a battery or not?

Also would you please check my recent post about detailed info about my build and help me troubleshoot it

Quote from: Lost_soul on October 27, 2024, 04:33:18 PMShould i do that test while connecting a battery or not?

I just assumed that. Yes, you should connect up a battery to the diode/MOSFET/resistor/LED.

Quote from: R.G. on October 27, 2024, 04:52:28 PM

Quote from: Lost_soul on October 27, 2024, 04:33:18 PMShould i do that test while connecting a battery or not?

I just assumed that. Yes, you should connect up a battery to the diode/MOSFET/resistor/LED.

I did the test using a 86k resistor and the LED worked!
Although not being as bright as when i tested it with a 3v CR type battery.

That means that the problem of getting no sound is with the board itself? Maybe the mosfet having 0.03v at Source (almost zero) have something to do with that?

And why doesn't it light up even if there is something wrong with the main board?

Good! I've posted some things on the other thread for you to try. We'll assume that the Millenium is working, and try to figure out what's wrong with the SHO circuit over there.

Quote from: fryingpan on October 27, 2024, 03:33:00 PMBut what is the real advantage of the Millennium bypass these days? Back then, 3PDT may have cost a fortune, these days not so much.

same now as then. you don't need an extra pole, a bigger switch, a part you don't now, never have, had. afford or not.

it's also a building block you can use all over the place, switching and indicating, and still only a double pole.