I just finished building my OTS 100. While I am nowhere near a tube electronics expert, I have succeded building 5 amps in the past (from plexi clones to twins) and this is my first amp build that deals with channel switching and relay boards. The problem is that while my clean channel works perfectly, when I switch to OD the amp squeals and if i turn up the overdrive control there are repetitive loud bangs happening together with blue flashes in the output tubes. Has anyone experience a similar scenario? Please help me!!!

My voltages are as follows:


Tube   Type    Pin1     Pin3   Pin4   Pin5   Pin6      Pin8   
                              
V1   12AX7   174.7   1.85         137.5   2.37   
                              
V2   12AX7   182      1.89         156.2   2.24   
                              
V3   12AX7   290.3   61.6         280.7   61.6   
                              
V4   6L6GC   39.2mV   450   445   -42   447      39.2mV   
                              
V5   6L6GC   41.6mV   447   445   -42   448      41.6mV   
                              
V6   6L6GC   40.5mV   450  445   -42   447      40.5mV   
                              
V7   6L6GC   39mV   447  446   -42   448      39mV   
                              
HT   350                           
HT   350                           
                              
OT CT   450                     

THANKS IN ADVANCE!!!!