A colleague has two ORIGINAL U47s with the original "Stahlrohren" tubes in them.
Another local chap has a 'Blue engineering' U47 with the EF86 mod.
You Simply Will Not Believe How much poorer the EF86 Version Sounds.
Seriously.
No no no no no.
It is NOT a god way to go.
It will NEVER be a U47 with this mod.
It's midrangey and it 'barks' at you.
Don't do it.
No.
-If you like, I can be firmer with my advice, but it involves cursing.
But seriously. It's NOT a U47. The G7/Lundahl circuit would beat it EVERY time.
Keith