The current carrying spec of of modern high output LEDs are much higher than an the 100mA rating of a 1N4148.The maximum current rating of a LED is much less than any diode.
From what I have read it's not that, apparently. There seem to be noise reasons or distortion, that makes LEDs behave better than those diodes in audio.I would presume the main benefit is you get a free indicator to show things are working.
Two 0.65V diodes in series are 1.3V but a red LED is about 2V, a huge difference. You would need to re-design the circuit to use a red LED.I just simulated replacing two diodes with a red LED on an amp, in LTSpice, and distortion went up, not down.
It rather depends on what the diodes were doing in the circuit?, you can't just randomly replace diodes with LED's and expect things to work correctly.From what I have read it's not that, apparently. There seem to be noise reasons or distortion, that makes LEDs behave better than those diodes in audio.
I just simulated replacing two diodes with a red LED on an amp, in LTSpice, and distortion went up, not down.
RadioSHack used to sell a several-Amp regulated-DC power supply where the reference was a Red Led...i've seen LEDs used as the reference in current sources for audio power amplifiers. not only do they work well, but also provide a visual indication of whether the current source is functioning normally.
As have I, but the circuit was designed to use an LED (of that specific colour), it wasn't randomly changed from a diode to an LED with no consideration.i've seen LEDs used as the reference in current sources for audio power amplifiers. not only do they work well, but also provide a visual indication of whether the current source is functioning normally.
This really does all depend upon the context of the circuit. We'd have to know what the intended function of the diodes was in order for anyone to make an informed comment on this.From what I have read it's not that, apparently. There seem to be noise reasons or distortion, that makes LEDs behave better than those diodes in audio.
yes, the LED is chosen for a particular forward drop, and to maintain that particular voltage drop, i wouldn't be surprised to find the amplifier manufacturer doing sorting/binning of the LEDs to insure the forward drop is within tolerance (or selecting a trimming resistor during board test to keep the output current within spec if the LEDs have variations in Vf).As have I, but the circuit was designed to use an LED (of that specific colour), it wasn't randomly changed from a diode to an LED with no consideration.
I don't think it usually matters that much, the sort of application that uses LED's in this way is commonly a constant current source, and it doesn't really matter much exactly what the value is, as long as it's constant. So simply using an LED of the correct colour is normally all that's needed.yes, the LED is chosen for a particular forward drop, and to maintain that particular voltage drop, i wouldn't be surprised to find the amplifier manufacturer doing sorting/binning of the LEDs to insure the forward drop is within tolerance (or selecting a trimming resistor during board test to keep the output current within spec if the LEDs have variations in Vf).