Alright, news. Went out and bought 0,2mm wire. Oh joy, it works better on low strings and does its thing on highs too. But it does it weak. The strings sustain but still don't pass the infinity mark. Maybe it's because I'm using 1/2 of a humbucker to drive the ruby. Does that give too little output? I don't think so...
It could also be because I'm using rather long wires to connect pots, jack, perfboard, the driver, etc.
What do you think?
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Jimbo