Anybody tried KT120 tubes on Conrad Johnson amps?

Well I service C/J as well as ARC and it's funny you mention it because I asked them about KT-120's last week. Their answer was..."We do not plan on using that tube". So there you go. Because of the increased heater current when using the KT-120 it's possible they would not be compatible. I'm just speculating as they did not give me a reason.

Br3098 I totally agree with you. Caps can make a huge difference and not all caps work well as coupling caps. There are caps I would use for crossovers that I would never use for coupling caps and vice versa. The bottom line is: all these tweeks, be it caps, or tubes, or speaker wire and interconnect cables are tone controls. Shaping the sound to the room and your taste.

Karma if you want to upgrade your amp replace all the electrolytic caps in the amp if you haven't already. That will make a huge difference especially if that amp has the old style twist lock lytics on the high voltage side. ARC's upgraded caps have an adapter on them. They are not twist locks but with the adapter plate they provide it's a drop in replacement. Twist locks have high ESR. When I upgrade an ARC amp I always replace them. Also I don't have a circuit diagram in front of me but if you own the MKII servo and your so inclined I would find a better ic for the servo. Put in an IC socket so you can easily remove them. Servos IC's do have a sonic impact. Servos were a good idea at the time, but they're not really used all that much anymore.

Wow rude and arrogant...Don't quit your day job...

Apologies to the room. My last comment was inappropriate and not constructive.