I decided to retube my SVT-3 Pro with better quality tubes. Got some TungSol gold to replace the Groove Tubes 12AX7, but decided to keep the EHX 12AU7. Turned the Amp on. The Gain light (PEAK) didn't even flicker, despite any gain setting. Also, got a horrible amount of distortion, for ANY gain setting, from none to max. The Tubes are new, and worked ok on a friends Marshall guitar amp. Putting the Groove Tubes back got the SVT-3 Pro to work ok. Did I do something wrong? By Caos I meant Chaos.