This is a rare early BTO Bass Head showing off its two large bass clefs.
If the two EL34 powered PRO model deserved a single clef than of course the
four EL43 powered BTO deserved two. The clefs on these early models were also
exceedingly large. They were later downsized and each head, whether BTO or PRO
received only one. Another noteworthy detail is the angled front panel.