No worries about sending a DM (Direct Message), this works fine. I believe there's some minimum number of posts you have to make before you can DM a TalkBass member. The only schematic that I have is for the WT500,WT600, and WT800 amps. The WT800 is the A model. When Marshall bought Eden, they put the Kabosh on providing schematics. You had to be an Eden Authorized Tech to get one. So I don't have that. However, Armin (
@Bassmann1968), who was the electronics guru on the Eden Forum may very well have one and can answer your questions if you drop him a DM. Or if we're lucky, he'll see this post and just answer it for you.
An interesting thing about the WT330 is that it was sold up until 2005 with the power listed as 330-watts rms into 4Ω. However in 2005, they changed the manual and put the WT330, WT390, and WT405 all inside that same manual. That's because they all had the same preamp and only the power sections were different. They also shared the same power section but had different power supplies. In the 2003 user's manual it lists the power as 200-watts into 8Ω, and 330-watts into 4Ω. In the June 2005 manual it lists it as 200-watts into 8Ω, 330-watts into 4Ω, and 420-watts into 2Ω. The WT405 was the last iteration of those WT330,390, and 405 models and it came out in 2004. It may very well be that when they made the WT405 model 2Ω capable they did the same with the WT330 and 390, before they updated and consolidated the manual in 2005.
And, to further confuse things, if I recall correctly, they did offer power upgrades on both the WT330 and WT405 to the same power as the WT405 came with standard. Your best bet on figuring this one out is to contact Armin
@Bassmann1968. He can get into the weeds with you about the wiring and values of the various components used in building it.