Tube Amp Archive

...and thanks to Loudthud for suggesting the on-on-on switch. Like others I'd seen these used as combination power and standby, but here in this thread are two new tricks.

Jhass, you could now use a second switch to do the Hi/Low inputs

The schematic shows pins 4 and 5 as connections to the heater in one of the two triodes, which is not the case. The actual arrangement is as shown below. The resistor values are different to get a better balance on the +12 and -12V supplies.

Shhh! Ladies present...

On 1) no,it doesn't matter they are carrying AC. No problem on 2) either.

Looking at the schematic, jumping R147 is not giving me enough negative sweep. Would it be feasible to jump (or run another resistor in parallel to) R111 and R114 to achieve a sweep further negative? My issue is not knowing where to start in order to calculate what resistance would put me in a safe...

I think what you have going on is chatter. The cutter falls into a repeating pattern of digging in and releasing when the chips break off. Try running the speed up or way down, and slow down your feed rate. Multi-fluted cutters seem to do this more readily, so maybe a single-fluted cutter would be w...