Don't forget to add a series resistor to limit current. Otherwise it will glow quite bright (but short).
2.5 mA is enough with modern LEDs for a normal glowing LED. So: (U - Uled)/0.0025 = x Ohm. Uled is dependent on color but 1.8V is OK for green/orange/red LEDs. White and blue ones need 4V.
If you like the LED to light your living room you can calculate for 10 mA.
I don't now how you built your F5 and with which PSU but you can use either the positive or negative rail to feed the LED.
Some wind a few extra windings on the toroid for a few Volts just to power the LED. You will need a diode and filter cap in that case to rectify the AC voltage. Elegant but more work.
2.5 mA is enough with modern LEDs for a normal glowing LED. So: (U - Uled)/0.0025 = x Ohm. Uled is dependent on color but 1.8V is OK for green/orange/red LEDs. White and blue ones need 4V.
If you like the LED to light your living room you can calculate for 10 mA.
I don't now how you built your F5 and with which PSU but you can use either the positive or negative rail to feed the LED.
Some wind a few extra windings on the toroid for a few Volts just to power the LED. You will need a diode and filter cap in that case to rectify the AC voltage. Elegant but more work.
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I think the OP deserves an answer...
Have a look at the schematic for the B1 buffer. In your case, you will be tapping the DC from a point after the smoothing capacitors the F5 power supply. The schematic will show you an example of the necessary resistor that will dim the brightness on the LED (as mentioned by others).
It is a straight forward job, but pay attention to polarity. Good luck.
Have a look at the schematic for the B1 buffer. In your case, you will be tapping the DC from a point after the smoothing capacitors the F5 power supply. The schematic will show you an example of the necessary resistor that will dim the brightness on the LED (as mentioned by others).
It is a straight forward job, but pay attention to polarity. Good luck.
Originally Posted by losacco View Post
Just finished F5 build, powered up and sounds good but NO LED light up on board. Will this affect performance of amp?
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Okay, I am confused. The original post (in this thread) implied that he wanted to add an LED to an F5. Now it looks like there was an LED installed but it was not working. What gives?
Just finished F5 build, powered up and sounds good but NO LED light up on board. Will this affect performance of amp?
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Okay, I am confused. The original post (in this thread) implied that he wanted to add an LED to an F5. Now it looks like there was an LED installed but it was not working. What gives?
Why ? You should use only some windings with isolated wire. Tie them together and finish the cables with one heatshrink tube just like the other secondaries. The rubber rings will protect the wires. I really like the concept and have seen it. I never did it myself probably because I only built lower voltage amplifiers where the LED + resistor was sufficient.
The LED + resistor are so common that any builder should be able to calculate and make that work.
We can discuss hundreds of pages about capacitors but please let'a agree that a LED either works or not. If LEDs also can work better .....
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