This is a barber LTD clone and it uses the exact schematic that is given in Barber site.
Fine, congratulations, re-check it anyway.
Even after thousands of amplifiers, each new one I finish building goes through the series lamp first, no exceptions.
Most times, say 95% , it comes alive with no hitches; yet a few here and there do not.
There's always the very minor problem which rises its head at intervals.
Oh well.
That's why even monster robotized factories such as Fender, Marshall, etc, regularly pull some amps from the assembly line for special checking, and most serious ones check *all* (even if only for one minute) , at least by strumming a few chords through them.
I have somewhere the famous picture of a *very* plain looking Chinese girl, clad in blue worker's overalls, with spectacles and ponytail, playing a very evil looking Death Metal guitar through Bugera heads prior to packing and shipping.
So, in a nutshell, building something apparently "by the book" is no 100% guarantee that it will work as expected or not need any testing.