Jab,
Bad tubes in certain conditions CAN damage the circuitry around if mistake had been made in supply resistor values that in fact should also act like fuses. The supply resistor should blow before the DC cap. After the DC cap blows the rest of the circuitry has 'no insurance' whatsoever.
As far as I've heard on few of their latest models the value of the grid resistor had been 10x the value should be so if the amp had been fixed it's not guaranteed that the next bad tube wouldn't blow it. For the reference I'd recommend comparing circuitry of predecessors that have similar design and values. ARC has circuit diagrams for almost all their products that they could fax or e-mail to you for no charge.
The positive side of this discussion that author Terry feels excited and optimistic compared to me...
Bad tubes in certain conditions CAN damage the circuitry around if mistake had been made in supply resistor values that in fact should also act like fuses. The supply resistor should blow before the DC cap. After the DC cap blows the rest of the circuitry has 'no insurance' whatsoever.
As far as I've heard on few of their latest models the value of the grid resistor had been 10x the value should be so if the amp had been fixed it's not guaranteed that the next bad tube wouldn't blow it. For the reference I'd recommend comparing circuitry of predecessors that have similar design and values. ARC has circuit diagrams for almost all their products that they could fax or e-mail to you for no charge.
The positive side of this discussion that author Terry feels excited and optimistic compared to me...