Also would you say the distortion in the higher feedback levels is normal?

Hey Scruffie!

Thanks for the speedy reply, I was working til late on last night and I’ve only just seen this.
I was thinking the same about the resistor but it’s a carbon comp and I’m pretty sure (from memory as I’m at work atm) the pot is a 100k (CTS with a white shaft) which the schematic calls for?
And thanks so much for that biasing info, I’ve only had the thing a few days and not really ventured down the rabbit hole with regards to the schematic and I’ve not had the board out of the box as of yet. I assumed there would of been a few to tweak on the populated side as per the poly chorus but with your advice/looking at the schematic I see there’s only the one which is trace side on mine.
As soon as I get back home this evening I’ll confirm the stuff I’ve recalled from memory and I’ll make sure I’m getting 6.7v on pin three of that opamp. Is this – https://sites.google.com/site/electroconducive/EHXPolyphase-Factorylessclear.jpgschematic all accurate? I know sometimes things get changed during production and schematics don’t get updated. Only reason I’m asking is I’m also going to check all the caps that have been replaced are the right value too.

Thanks again for the reply Scruffie, your help is greatly appreciated