Pedals that stack with the Marshall 1987X Plexy 50W Head

pushes an already-dirty tonePushes an already-dirty tone harder and tightens it up. (crunchy → clean boost)

Beetronics Buzzter Boost Preamp pushes a crunchy tone toward clean boost

Goes in front of the amp

fills a frequency gapFills in a frequency range the other side doesn't cover, instead of piling more onto what's already there. (bright → smooth)

Xotic BB Preamp's own bright character is the real reason this is worth trying

Goes in front of the amp

pushes an already-dirty tonePushes an already-dirty tone harder and tightens it up. (crunchy → mid-forward)

Feed a crunchy signal into Univox Super-Fuzz and it comes out closer to mid-forward

Goes in front of the amp

sits in the right chain slotPlaced for where it does its job cleanly in the chain, not for a tonal interaction with the anchor.

Run Origin Effects MAGMA57 Amp Vibrato & Drive after Marshall 1987X Plexy 50W Head in the signal chain, clear of Marshall 1987X Plexy 50W Head's own gain stage

Goes in front of the amp

shapes the dynamic responseShapes how the tone responds to picking dynamics rather than its frequency or gain. (dynamic → compressed)

What HomeBrew Electronics CPR Compressor Retro brings here leans toward compressed — that's worth building a pairing around

Goes in front of the amp

Keep Catalinbread Dirty Little Secret Deluxe in Marshall 1987X Plexy 50W Head's effects loop, clear of Marshall 1987X Plexy 50W Head's own gain stage — goes in the amp's FX loop (or last, into a clean amp)

Sits in the amp's effects loop

sits in the right chain slotPlaced for where it does its job cleanly in the chain, not for a tonal interaction with the anchor.

Run Caroline Guitar Company Kilobyte in Marshall 1987X Plexy 50W Head's effects loop, clear of Marshall 1987X Plexy 50W Head's own gain stage — goes in the amp's FX loop (or last, into a clean amp)

Sits in the amp's effects loop