Kudos to Audio Research

Audio Research guarrantees their tubes for a time period so if they take out an amp, they should repair it, and obviously do.
Regarding a tube taking out the resistors and some circuit traces, Audio Research feels, I think, that there are compromises inherent in designs which protect the amp in the event of tube failure. It would obviously be easier on them the design amps that way, fewer repairs, but they are a perfectionist company and strive to have no shortcuts to sound quality. I am not saying that other companies are taking shortcuts, just a different approach.

It seems some are missing the original point of the post. The amp owner is giving praise for great product support from the mfg. This stuff is electronics and yes "sh** happens". With all the bagging that we've seen on this site in regards to bad product support, it seems the mfg. did a good job of keeping a customer happy. Praise is certainly in order.
-John

I have to say that my experience with cj amps is exactly the opposite of Jwm's. I've owned cj amps for over 20 yrs, beginning with the MV75A1 and currently the LP 150 Ms. The amps have been like battleships and have never once had a bad or old tube take out the amplifier.

Once I had a resistor go in a 8 yo MV75A1 and the amp had to go back. That would have held true whether the amp was ss or tube in this case.

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...