I think I’ve found the problem. I touched up the solder joints for the blend pot and ran into the same issue again tonight. When the pedal started freaking out again, I unplugged the power supply from it and stuck a multimeter on the power supply – turns out the PSU (the original EHX one) is putting out 28v instead of 18v – which, no doubt explains the pedal heating up.

The pedal will be pulled from my pedalboard until an appropriate PSU has been purchased. Then, and only then will I be sure that this is the source of the problem, although right now I am inclined to believe that it is the source.

*crossing my fingers*

My thoughts exactly, although I did see at least one other post on HC user reviews about a holy grail overheating – which led me to wonder if the heating up is a commonly observed phenomenon with these pedals.

If anyone reading this owns a Holier Grail, could you please do me the favour of touching the top of the pedal casing between the Type selector and the Gate Threshold knobs after the pedal has been on for a couple of hours and tell me if it is warm/hot to the touch? Even a Holy Grail might give some indication (not sure if it uses the same DSP chip though).

The adapter is 500mA, which is a decent amount of current for a small device (and I realise that it’s highly unlikely it would be operating at capacity ever, let alone all the time) and some digital chips do get pretty hot with prolonged use (like the ones in computers which need fans and heat sinks).