OP Amp Preamp - inside the case

On the test bench for a short run-in period. The lids off waiting for smoke. No smoke but on the first start there was a minor fault. I have been listening to the preamp for two hours now and found it adds nothing to the sound (as a preamp should) and extends control with volume and balance adjustment. The yellow caps are 0.47 uF polypropylene metal film. Full details are available for this project at: DIY Op Amp based Preamplifier Project.