I open up and take a look at the Bugera 1960 clone of the Marshall 1959 Super Lead. I inspect the circuit and compare the schematic.

0:00 Behringer Amp Clones
1:27 Control Layout
2:15 Built in Cascade Mod
3:31 The Master Volume
4:47 The FX Loop
7:58 How to add a Proper MV
9:36 Stock tubes
10:33 The Box & Upholstery
10:59 Looking Inside
13:44 Infinium Module
14:26 Infinium Roughly Explained
16:20 Master Volume Potential
18:20 Rigidity ?
18:53 Testing the Stock Power Tubes
20:22 The Tube Sockets
21:14 Circuit Analysis : Power Supply
22:11 Filament Supply
24:07 Preamp Ch1 Bright
25:09 Preamp Ch2 Dark
25:20 Stage3/Follower
25:35 Tone Stack
25:59 Phase Inverter / Feedback
26:59 Power Amp
27:29 Cascade Version Preamp
28:15 Closing Thoughts