What Tim Marcus said, is great advice.
I think if the Milkman The Amp 100w had two separate input channels that would be my answer, but sadly that's not the case.
Ben, don't let the fact that the gorgeous Milkman The Amp only having one input, is a deal breaker. The Amp is such a fantastic sounding portable sweetheart, Tim can help you with a workaround I'm sure. Taw me.... I'd just do this easy fix. Then put the little box in the back of your amp. Simple fix.
https://www.sweetwater.com/store/detail ... e-switcher
Actually what tim suggested is about how I do it. Now to be perfectly honest, it's been years since I've played any instrument through a completely clean, one sound fits all Solid State (do they still call them that?) instrument/steel amplifier. Cain't even remember what that was like, and prefer not to.
I currently own 14 "Perfect" double duty amps, half my amps will fit in the palm of my hand, and will fit in my pak-a-seat. No need to make extra backbreaking trips to the car, just because you use one of those gawd awful, scarry, heavy, high maintenance, overly loud, misinformed about, i cain't find MY TONE on, or i'm too damn old to tote, whispered about, swore at, just too much hassle to use, taboo tube amps LOL. Just teasing. Especially not if you purchase the right amplifier, and-learn how to set it up correctly. I'm ummm ummm 70, and wouldn't dream of playing through anything else. Retire? From what? Shoot I've been retired most my life. Why in the world would I retire from something I love? For maybe what, stamp collecting or shuffleboard? Nah...that would certainly kill me from boredom.
There's more to playing Steel Guitar in public, then just sitting behind it and putting on a show. Transport and setup, are part of the experience for me, even with agonizing years of home practice & not to mention the investment you've made.
Disclaimer:
I rarely load, pack, carry, and on most gigs setup my own gear. I do certainly oversee all aspects of the operations.
However I tote each piece with pride when I need to.
All my amps are single channel amps, although my MesaBoogie JP-2C is a big 3 channel 100 watt concert monster, with 2- 5 band graphic eq's, cabinet clone, midi, loops, and the kitchen sink on the back side. My Boogie does actually get as quiet as a church mouse in my living room, surprised me actually. Today a stock Boogie JP-2C Amp is around $3,500 and weighing about 40 pounds. In actuality, mine is closer to $4,000 and hitting 50 pounds with the mods, exotic woods and custom cabinetry I had done. Nope, I didn't mind dragging my old Peavey Session 500, or my Fender SteelKing 'round neither.
https://www.mesaboogie.com/en-US/Produc ... /JP2C-Head
Exclusively running Rick Johnson Cabinets, loaded with Eminence, Peavey 1501-4 SB Neo's, Jensen Neo's, Weber D130 Neo Clones. My Johnson Signature "George Redmon Tall Boy 12" i keep loaded with Celestron Copperback Neo 12's.
My only experience through several years of listening to many Steel players who try using a single Amp for 2 or more instruments, was somehow, and I know they had to work hard at it, was somehow they took forever twisting knobs, until their steel guitar, and strat, both sounded durn near identical. Sounded just like a steel player, playing electric guitar, that sounds like his steel guitar. Well.......
Much success on your search for that "Perfect" all around double duty amplifier.
"Single Channel Tube Amps Rule"