Ring Frobnicator Saga part III

[jrc4558]

Ladies and Gentlemen! hehe...
well, my third attempt at building this device came very close to be a success. 1) The LFO is working. 2) The audio signal is coming through. These two things never happened toghether at once in any of my previous build attempts. The problem is - there's very little (barely noticeable) amplitude modulation. Maximum depth of tremolo gives me almost no modulation (something like minimal depth on the ROG EA Tremolo adaptation).
The bias was set with three 3mm LEDs; the LED and the 1n914 feeding the OTA's pin 5 are oriented properly...
Aside from the obvious "What should I do?" I would like to ask you all, pretty people, to enlighten me on the theory of OTA's, or to recommend some good source on the abovementioned subject for a semi-advanced DIY tweaker.
Thanks to all.

[MartyMart]

I used the same batch of LED's ( 3mm red ) and a 1N4148, plus a trimmer
instead of the 10k from 9volts.
Worked first time, give it a try.
BTW I didn't use three LED's where you have, only two .....
2x LED then 1xLED&1N4148

Marty.

[brett]

Hi.
Because the OTA modulates the signal according to the current at the control pin, you might want to check that current into that pin is going up and down in time with the LFO leds.  No current variation, no modulation.
Sounds like you're a whisker away, so keep at it.
cheers