My issue is that it (the led) is ALWAYS on... I have one leg connected to 5v and one to pin 8 of lm567.

Please tell me you have the 470 resistor in series with the LED.

Ken

 

I have a 68ohm resistor in series w/ a high brightness led.
Tried 470 for hell of it did nothing.
What DOES happen is that when I have a very low frequency, the light turns on and off to the beat of the amplitude. Its like the bandpass is HUGE...

tried different chips, will tinker w/ the source today. Suggestions much appreciated

 

I don't get it. The guy says that output goes low when tone is detected. Doesn't that mean the led should turn off when the tone is "heard"? He goes on to say turn pot until led is illuminated?

When the output is low, the LED energizes.

Have you done the calculations, see page 8 of the datasheet, to see what frequencies and bandwidth you are dealing with?

If you are using that schematic, the frequency definately is about 9k to well above 20k

 

Hard to guess at what your problem is. Any chance you have a scope and a function generator to do some troubleshooting with?

I breadboarded one with 2.2uF on pin 2, 1.0uF on pin 1, 0.1uf on pin 6, and 1K resistor and 10K pot in series between pins 5 and 6. Led lit from ~880Hz at 11K to ~8.8KHz at 1K, over the pot range. Input was ~0.5Vpp through a 4.7uF cap.

Ken