I picked up a Darkglass Vintage Microtubes a month ago, but it was bloody noisy BUZZZZZZZZZZ!!!!
Even with the input muted (at the tuner).
So, I took it back out of my pedalboard.
I went back to Wunjo and they put it alongside another Darkglass one; with all the knobs turned up full, it buzzed too.
So, I got a refund.
(Thanks to Wunjo for their great customer service!)