Feedback on new build - literally

[JMPGuitars]

Please post the layout and schematic of your build so we can help you troubleshoot.

V6 is switchable, yes? Do you get that feedback with el84s, 6v6s, or both?

And just because, do you have any acoustic guitars in the room that might be faking the feedback for you?

All things considered, I would finish the amp before fretting too much.

Thanks
Josh