I'd like to find out some info about using the Ampeg PF20T Preamp DI on Pre-EQ mode but don't understand block diagrams. I'd like to understand if in Pre-EQ, the signal goes through any of the preamp valves or if it's just Thru. The manual and diagrams get confusing as one section says in Pre-EQ it acts like a Thru but in another it states the Pre-EQ is after the first gain stage. The block diagram (to me) looks to show three preamp valves but there are only two. Hence my confusion.
Below are screen shots of the FAQ about the Preamp DI, and the block diagram. I've included a link to the owner's manual. https://ampeg.com/data/6/0a020a3f12c8b5e0b88f60b5ae/application/pdf/Owner’s Manual - English .pdf
Any help is appreciated.