I've read on other threads people asking for the voltages on the Origin 20. There has also been speculation as to how Marshall is doing their power scaling. It is not what it was thought to be!
Here are the voltage readings on the plates for V1 - V5, going from "low" power mode to "high" power mode:
V1 ------- low ------ mid ------ high
pin1------175v------166v------151v
pin6------152v------145v------133v
V2 ------- low ------ mid ------ high
pin1------274v------262v------236v
pin6------151v------145v------131v
V3 ------- low ------ mid ------ high
pin1------39v-------70v -------149v
pin6------39v-------72v -------150v
V4 ------- low ------ mid ------ high
pin3------307v------293v------262v
V5 ------- low ------ mid ------ high
pin3------309v------295v------262v
Do you see what I see? V3, the phase inverter, is being choked out in low to mid power mode! That's how Marshall is getting the volume drop. It also sheds light on how important the phase inverter is to the overall sound of the Origin series amps. I'm sure you can get some very different tone out of them by trying different valves in V3.
Here are the voltage readings on the plates for V1 - V5, going from "low" power mode to "high" power mode:
V1 ------- low ------ mid ------ high
pin1------175v------166v------151v
pin6------152v------145v------133v
V2 ------- low ------ mid ------ high
pin1------274v------262v------236v
pin6------151v------145v------131v
V3 ------- low ------ mid ------ high
pin1------39v-------70v -------149v
pin6------39v-------72v -------150v
V4 ------- low ------ mid ------ high
pin3------307v------293v------262v
V5 ------- low ------ mid ------ high
pin3------309v------295v------262v
Do you see what I see? V3, the phase inverter, is being choked out in low to mid power mode! That's how Marshall is getting the volume drop. It also sheds light on how important the phase inverter is to the overall sound of the Origin series amps. I'm sure you can get some very different tone out of them by trying different valves in V3.