[sdiy] can I make this circuit change?

[Oren Leavitt]

Hi db again,

Following up on my previous email...
Easier still, you might try adding a resistor between V+ and Q101's 
base. Try about 68K for a start. The aim here is to pull the DC voltage 
at Q101's base up just shy of the 1.2V bias needed to turn on the 
transistors. A small added AC signal will be enough light the LED. You 
can tweak this added resistor to set the desired sensitivity without 
having to change any other [arts of the circuit.

OTOH, as Mark said, you may want to keep the overload indicator as is 
and just add new circuitry for an additional "signal present" indicator LED.

- Oren


db wrote:
> 
> 
> On the schematic here:
> http://workingdistance.com/temp/mixer.jpg
> 
> I lowered to r104 to 1k, and even then still not quite enough to light 
> the led on regular signal levels. :(
> 
> I normally keep input gain (VR101) all the way down.
> I don't really understand how in this circuit the gain knob affects the 
> led - it looks to me like the signal to the led circuit would be the 
> same regardless of gain setting.
> 
> What am I missing?
> 
> Anything else I can try in this circuit to get some more ooomph to the 
> leds?
> 
> I have 16 channels to do so I'm hoping for simple..
> 
>  >I have a mixer with an input led for *overload*.
>  >I was going to add LEDs for showing signal is present in the input, 
> but seems easier if I just make this led signal regular input instead of 
> overload.
> 
> 
> 
> dennis.barton:skylab2000[socal]
> 
> 
> 
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