Small Stone home made: problem with "color"

[psst]

Hi!
I finished my Small Stone, works perfectly, compared to my original '79, no difference.
I have a problem, though. When color is activated, no sound from the guitar comes, but a very LOUD "siren" sound, like what I'm hearing is the LFO phasing.
The color switch has two parts, if I remove the "feedback increaser" one, it works ok (meaning OK that the "siren" disappears), so there's the problem. No problem with the part that goes to the LFO generator.

Any clues of what's happening?

Thanks!

[puretube]

10 times wrong resistor value