Rate LED switching

Started by armdnrdy, October 10, 2015, 07:39:29 PM

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armdnrdy

I have a question regarding an aberrant method of switching a rate LED.

The image below shows the LED being switched off by switching the ground from the emitter.

I know that the usual way to do this would be to bring the base low but...this switching arrangement also doubles as a effect in/out indicator, and I do not want the LFO anywhere near the input/output switch. It's easier to switch in/out the ground as you would on a stand alone LED.

I've bread boarded this circuit and it works with no issues but...is there any reason why this can't be implemented?

Here are voltage measurements of the tranny pins with the LED on and with it off for comparison.

Collector
ON             OFF
7V              7.5V

Base
ON             OFF
min/max    min/max   
.63V-2V     .63V-2V

Emitter
ON              OFF
min/max     min/max
.74V-2V      2.3V-2.9V

Here's the image of the circuit in question:
Edit: Disregard the 47R resistor between V+ and the LED. 

I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

PRR

That should work.

> I do not want the LFO anywhere near the input/output switch

Looks pretty "near" to me. Bottom of R92 is bob-bop-bopping with the beat, no?
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armdnrdy

Good catch Paul!

Yes it is bee bopping along isn't it.  :icon_redface:

The switch is mounted on the board. R92 is placed away from the switch.
The input lug is separated from R92s "switched ground" trace by a "dedicated" ground trace.
Hopefully there won't be an issue from the LFO signal.
If there is....I'll ace the flashing rate LED and make it a straight on/off indicator.
I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)