DIY Amp

I haven't built one but it's got very good reviews by those who did.

Decware ZKIT60 SS 60W per channel stereo amp.

https://www.decware.com/newsite/ZKIT60.html

Bottlehead?

They offer 2A3 mono's and a 300B that can be done as  mono also I believe.

Nice kits and a great support community!

Hello ecpninja!  As the happy owner of an EleKit TU-8600R, I am sure you would be happy with it. Get the version with the fancy output transformers etc. It is not cheap but it is often talked about by reviewers and performs extemely well. Put a Telefunken 12AX7 in the input tube socket and be amazed. Use efficient speakers. 90 watts is only 10db louder than 9 watts. 10 db isn't all that much unless you are trying to break a lease or get your wife to leave you. Happy building!

The Elekit looks like a very promising project and the pedigree looks good

Thanks for the link

Another option are the kits by Triode Electronics out of Chicago.  Basically modern Dynacos from the ST35 and ST70 up to the Mk III amps. See https://store.triodestore.com/ampsandgear.html