I wonder if Bloomfield recorded through that Pro? Was it his?
They're great amps! Closer to a BF Vibroverb, without the reverb. I've got one. It's a 1964 production 1 AA763 Pro. I bought it from the late David Wilson, from the Tonequest Report.
Here's his article on my actual amp. It has a couple of small mods.
We called Paul at Mercury Magnetics and ordered a black-face Pro Tone Clone replacement trans-former, shut it down and wished each other a good holiday. A week later the Mercury Magnetics replacement output transformer had arrived.
www.mercurymagnetics.com
Btw, my oldest friend has a 1964 non-reverb BF Deluxe that he's had since the early 80s. It's a great sounding amp, as well. I love that thing...