I've just finished upgrading my Crack with the Speedball kit. Before the upgrade, the Crack was singing beautifully. Now not so much. When I did the voltage checks, everything checked out except for 15 and 21. 15 reads 230 volts and 21 reads 255 volts. I think that's a little more than spec. Also... when I check the voltage at the tip ring of the headphone out, voltage climbs to more than 30 volts then rapidly drops back down to zero. I plugged in some sacrificial headphones and hear a hum. If I touch the 12au7, I get a loud cracking noise. Same if I jiggle the headphone plug in its jack. Any advice on where to start troubleshooting?