Bi - Amping

I want to Bi-amp my speakers with different amplifiers / and diff brands
A21+ Anthem STR amp harman Kardon Signature 1.5 Citation 7.1
what are the consequence or disadvantages of not using the same Amplifiers ?

Thanks everyone for great response 
@almarg  anthem STR power amp 400WPC @8ohms  not integrated A21+300WPC @8ohms HK SIGNATURE 1.5 [email protected] CITATION [email protected] 
lordrootman OP

Halo A21+ on the mids and highs, because it’s "high bias Class A/AB operation" John Curl design, which will be better for the mids and highs.
And probably the Anthem ( Sixteen bipolar output devices per channel ) on the bass for the current in can deliver into 2ohms

And the Rotel Michi having 100ohm output impedance will have no trouble driving any combinations of amps you have

To me if you have the amps, it’s well worth doing as it will cost next to nothing to do and you’ll gain from it.

Cheers George.
Ensure that the gain on the different amplifiers are the same. 
Ensure that the gain on the different amplifiers are the same.
They won't be, and that's what the $49 Schiit Sys passive is for.

Cheers George
Sounds like a valid experiment. 
I might try this instead for level adj.:
Then you can hear from your listening position if it is worth pursuing.
Try it with cheap cables first.
Let us know how it works out.