Hi everybody! New member here (and new Marshall owner!). For the last two decades I've owned a <hides> Crate Blue Voodoo 120H and decided it was time to upgrade to the tone I've been hunting most of my life. So, I got myself the DSL100HR, 412A cab and the 6-way footswitch from Sweetwater. Absolutely loving the tone, but I've run into something that I can't quite put my finger on. I've searched plenty, including this forum, but thought I'd get some advice on this specific situation. In my effects loop I have the Boss DM-2W (Waza Craft Analog Delay), and that's it. Literally the only thing in the loop. But, when I engage the loop I get an immediate tone and volume drop. Almost as if someone places a cardboard box directly over the cab. Disengage the loop, and we're back to normal. Here's what I've tried... 1) Patch into send/return - No problem 2) Plugged Waza TU-3W tuner into effects loop - No problem 3) Replaced The DM-2W with another unit - Same result 4) Plugged in a Tone City Tape Machine - Same result 5) Plugged DM-2W into Blue Voodoo effects loop to test - No problem 6) Plugged DM-2W into a Fender Princeton Chorus (not tube, but the only other amp I have) - No problem. 7) Removed DM-2W from power supply and put in a new 9V - Same result 8) Tried different cables, shorter cables, etc... - Same result As you can see I tried some pretty exhaustive troubleshooting. But it's neither seemingly the head (no drop when going straight from send -> return), nor does it appear to be the Boss itself? As you may be able to tell, I didn't try a buffer for a couple of reasons... the Boss already has a buffer, and being the only pedal in the loop should I really need it? I don't know where to go from here (Sweetwater is actually sending a new head, because they're stumped, too) but thought I'd reach out here and see if anyone else has noticed anything similar with this head, or has any other insight. Thanks! Happy to be in the Marshall family.