Tube amp question

OP, I would ask Mr. Allen to confirm that there will be no damage to his transformers by running the KT150’s...and maybe have him put that in writing. While the amp may supply ’enough’ voltage for the KT150’s to work, as russ69 pointed out above, you will not get all the power that the tube can produce.

Personally, I would be more concerned about using a transformer that was not originally designed for this tube, but if the manufacturer is ok with that..so be it.

Just a little more background here. The amp came with the EH EL34's. Having read a lot about the Genelex Gold Lions, I decided to give them a try (same EL34's). The sound quality was improved and I really liked them but they seemed to lack a bit of dynamics that I'm looking for. I am driving a pair of Legacy Audio Signature III's which are 4 ohm and 93db sensitivity. I'm looking for a bit more kick from them that I know they can provide.I purchased a quad set of KT120's and after allowing them to warm up, I biased them at 50mv per the manufacturer spec. I slowly raised the volume and after about 10 seconds the amp shutdown in protection mode. I emailed the factory and they believed that I must have a bad tube. This happened just after the Russian invasion of Ukraine and the run on tubes. I could not locate another set of KT120's anywhere. As I researched more I stumbled across a guy who had four remaining KT150's that are actually ARC matched. I am waiting for those to arrive. It will be interesting to see if the amp reacts the same or how it will perform. This damned Russia thing happened right in the middle of my experiment. But I don't at all want to devolve the conversation into politics. I appreciate everyone's insight

When I spoke with Jarred about this while helping a friend on his, they were open to the idea of running other tubes in the F22 yet there was little feedback and what the amp was really optimized for other than EL34s, originally.  For the little extra "kick" you are looking for, that's why I was recommending a slight jump up to nice KT88s [for this particular amp]. Who doesn't have 3-4 different sets anyhow, lol. :)   

Thanks, I'll see how the KT150's shake out and I may consider that.

So now we hear that the OP and one other member has had the same problem when running KT120's. The amp went into protection mode. I would think if it does that with KT120's...nothing good can happen when you roll in KT150's.