5F2 vs 5F2-A

[guitarstevie]

The omission of the choke and the filter cap changes I understand. I don't understand the differences between the volume and tone control of the 5F2 and 5F2A amps.
Those first 2 stages are coupled differently. CAN ANYBODY EXPLAIN WHATS GOING ON. AND WHY THE CHANGE WAS MADE. THANKS STEVE

[loudthud]

The 5F2 can only give a small amount of treble boost but it is constant regardless of volume control position. The 5F2A can give more treble boost but only when the volume is less than all the way up. When the volume is all the way up in the 5F2A, there is no treble boost.