KT120 transformer failures

With the KT-120 it is strictly an issue with the filament supply.

The newer ARC products have been designed with higher current ratings on the filament winding expressly for the purpose of using the KT-120. A few earlier ARC pieces, by virtue of their robust filament windings can also take advantage of the KT-120's. There are other ARC amps that can never use this tube do to issues where the length of the tube creates issues, i.e. cover will not go on or transformer in the way.

@Wolf...there's always a first time. @Smoffat if I get a chance I will talk to the factory about the CL-120/KT-120 issue and see what they say. I can tell you that the CL-120 has triode configured output tubes. The Ref 150 has a different tube compliment and does not run the output tubes in triode. I believe it runs the outputs in ultra linear configuration so it will sound different. Also, the CL-120 uses servos to set bias on half the output tubes and the cage must be removed in order to set bias. The Ref 150, I believe, allows user adjustment without going inside the amp.

@ Wolf Yes a CL-120 or Classic 120 was a tube amp made by ARC. @Smoffat, I don't believe the top cover will fit if KT-120's are installed.

Unfortunately, the CL-120 is not on ARC's list of products that can accept the KT-120.