Build a wooden crate or use a cardboard box for Amplifier.

For shipping my typical rule is crate over about 100lbs. Other than that double cardboard is fine if you don't use a gorilla carrier. Some hi-fi manufactures have gone to triple cardboard. Those Krell's are heavy, but if your using a moving company, my opinion is you don't need to crate.

Thanks for the input . Any basic design for the crate would be helpful

Build a killer wooden box with strong foam lining.

You can also use expanding packs. Get a heavy double or triple thick cardboard box with at least 2-3 inches all the way around. Make it if need be. Just cut down from a HEAVY Refer box or something like that.

Use reinforced fiberglass tape to hold it together.

Put heavy styrofoam blocks in place to center the amps in the box. Tape them in place.

Get  heavy plastic bags and bag the amp. Set your expanding packs in place. Place the amp on the taped styrofoam and set off the bottom foam bags.

Set the top bags, set them off, close the box, but don't tape it.

Inspect your work after they set up and see if they need trimming or an XTRA bag or two

https://www.uline.com/BL_7708/Instapak-Quick-Room-Temperature?pricode=WB140&AdKeyword=expanding%...

If you really want to go nuts build a 1.5 - 2 x 4" external frame with screws and glue. Remember don't glue what you're gonna take apart to get the cardboard box out of the wooden crate (has open slats).

I did the exact same thing BUT the inner box was lined with heavy felt and it was made of 1/4" ply wood and held together with leather belt straps..

I used that set up for 10 year traveling. Everything fit and was strapped to a dolly. A pair of MC30s and a C20, and all my needed STUFF. I NEVER broke a glass in all that time.. I worked on sea going tugs and mobile drilling platforms. It got rough out there sometime, pulling some nitwit off the rocks or foul weather hit...

Remember the Santa Barbra and  Exxon Valdez, I was there for both cleanups, what a MESS..

Regards

I double-cardboard boxed my PrimaLuna integrated using using plenty of foam and bubble wrap. It successfully made it across the seas by freighter with all tubes plugged in and intact.