How to smooth out blinking LED in tremolo?

[Philtre]

I've built the Heartthrob tremolo pedal (Schaller mod) - http://tagboardeffects.blogspot.co.uk/2012/03/heartthrob-tremolo.html - which is based on this schematic - http://www.mrdwab.com/john/temp/Schaller-Hearthob-conversion.jpg

I've hooked up an LED going from the collector of Q4 to ground so that it flashes in time with the tremolo frequency. But when it flashes it's binary on/off, meaning it's either full on or full off. It would be easier on my eye if instead it flashed full on and half off (or half on). I've seen this on a TC ELectronic Viscous Vibe pedal. Is there something I could add, like a capacitor, to achieve this?

[bsoncini]

Maybe try a capacitor in parallel with the led?

[Philtre]

OK, any idea what value?

[Rockhorst]

100nF or 1uF might be a good starting point

[bsoncini]

I stumbled on this thinking of a solution.
http://www.diystompboxes.com/smfforum/index.php?topic=24291.0

[Philtre]

I stumbled on this thinking of a solution.
http://www.diystompboxes.com/smfforum/index.php?topic=24291.0

That did it! Many thanks. :-)

[Philtre]

But I spoke too soon. 

The solution in http://www.diystompboxes.com/smfforum/index.php?topic=24291.0 worked in a small test circuit I breadboarded (https://www.build-electronic-circuits.com/wp-content/uploads/2014/04/Astable-Multivibrator-2LED.png) using a 100uF cap, but applying the same principle to the tremolo circuit didn't work. Values of 100uF and below did nothing and a value of 220uF stopped the flashing altogether. I guess it must be due to where I'm tapping the circuit for an led feed.

[Philtre]

In the end I just used a higher value CLR.