Hi,
I uploaded a DI profile of my Marshall 50 watt Plexi issue. The amp was set to be on the edge of breakup so it cleans up nicely when you pick softly or roll your volume control back a bit. It gets crunchy when you pick harder but it's definitely not a high gain amp. Try it with a vintage Marshall cab if you're looking for a late 60's to mid 70's vibe.
Brian