[wdahm519]

So I'm building a PIMETA v2.  The parts are on their way right now and I'm getting ready to do the build.  One of the last things I have to work out in my head is this:
 
1.) If I use both LED1 and LED2, will I still be able to do class A biasing?  
 
EDIT: Found the answer myself:
 
"If you’re using LED2 for a panel-mounted power indicator and are also using the class A biasing feature, add the LED1 and RLED parts now. This is some combination of jumpers and diodes, depicted and described elsewhere. Regardless of how exactly you set this up, these parts need to go in now."
 
2.) What is the advantage of using both LED1 and LED2 together in class A biasing?
 
3.) Is it more advantageous to bypass LED2 and jumper it for class A biasing?
 
 
I feel like the explanation in Tangent's guide didn't quite answer this, at least for me.  
 
 
Thanks,
 
Werner
 
 

 

[wdahm519]

Anyone?  I'd really like to know what the point of having both LED1 and LED2 is for class A biasing.

 

[tangent]

Quote:

2.) What is the advantage of using both LED1 and LED2 together in class A biasing?

 
LED1 is required by the class A biasing circuit. The circuit's operation is described in the documentation. The docs give you an alternative to LED1 here, but the fact remains that something with a constant voltage drop must be in this position in the circuit if it is to provide class A biasing.
 
LED2 exists purely as a way to harvest some current that would otherwise go to waste in this circuit. As a nice side effect, it gives you a way to get a constant-brightness LED with battery-powered amps. LED1 will dim as the battery voltage drops, unless you replace RLED with a CCS, as described in the docs.
 
 
Quote:

Is it more advantageous to bypass LED2 and jumper it for class A biasing?

 
I think you're making an incorrect assumption. You can use LED2 for illumination and have class A biasing at the same time. The question is not a matter of which option is more advantageous. The choice to use LED2 simply comes down to questions like whether you'd like to have a second LED, whether you want a constant-brightness LED, whether the waste current path bothers you, etc.
 

 

[wdahm519]

Ah okay, I think I better understand whats going on here now.  Thanks tangent.