Thanks again. Checked and no ground circuits around the correct sides of R20. Perfect sound with audio probe at pin 6 of IC1. I also tugged all the wires to see if I could get disconnection and no go. If I strum hard then the higher level signal kicks in whatever’s not working and it works. Then a second later as the strum dies down there’s a step change down.
I’ve pulled out Q5 and will pick a new one up from Jaycar this afternoon and socket it to eliminate this.
On the 45 setting the pedal is perfectly usable as a phaser, sounds great with no noise. Just odd it’s a no go on 90! For another $2 might get another TL074 as well – I’m assuming you couldn’t have a partially faulty IC?