Inexpensive Tube Amps

Anyone have any experience with the following?  I want to try one just to see how the sound compares to my Yamaha and Denon solid states.  Since the Denon is living on borrowed time I will likely have to replace it this year anyway.  Looking at the Nubsound and noted a Germtune that is identical to the Nubsound but costs a bit more.  Reviews are largely good including those on other forums.

https://www.amazon.com/dp/B00NWISSGU/?coliid=I2VYW63Z6R35ZH&colid=3O2PB0XPYIL0T&psc=0&re...

https://www.amazon.com/Nobsound-Amplifier-Single-Ended-Handcrafted-Headphone/dp/B073ZXZ3Z5/ref=pd_sb...

https://www.amazon.com/dp/B00DRUY6EG/?coliid=I1EPHIQ7T6OOPR&colid=3O2PB0XPYIL0T&psc=0&re...