Retubing an ARC VT100 mkll

Gary, I'm sure you're right. But I wonder if the KT-120s are as susceptible to arcing or other malfunctions that would damage the amp as compared to the 6550 C tubes. The build quality impresses me that the KT-120 may have a longer life than 2000 hours.

I can tell you, they're still susceptible. If your amp was wired in triode, you might be able to get away with it.

Gary,

Is the ARC VS 115 wired in triode?? Regardless, thanks for the advice anyway. The 6H30 audio tubes were pushing between 4 and 5K hours too. So I retubed the whole VS 115 batch.

As an aside, I just ordered a retube set FROM ARC for my ARC Ref 5. There's probably over 3K hours on the 6550 C and 4 to 5K hours on the 6H30s.

Not sure what I did makes sense, i.e., buying VS 115 tubes from Upscale Audio and Ref 5 tubes from ARC. The thought process is that "ARC grade" matching might be more critical in the line stage than the amp. That's probably not a valid assumption, but it's a done deal. In any case, as stated, the KT-120s bias just fine and the amp sounds great, so I'll just have to "suffer" [sic] with the Upscale Audio tubes in the amp -- NOT.

Next time let me know BEFORE you buy your tubes. I can help.

No way the vs115 is triode. 4 tubes push pull per ch will not get you 110wpc even if you push B+ all the way to 550v.