I did that with my Benchmark LA4 preamp and CODA 07x preamp. One was neutral and clean and the other was a bit warmer. I had a real complicated setup there. There were 2 DACs going into each preamp with RCA and XLR, 2 tuners, one by both RCA and XLR, SACD player. I also had a second amp on the CODA 07x via XLR to the amp for my RAAL SR1a headphones. The CODA also had an XLR going to my speaker amp(s).
When I wanted a more neutral sound I would change the speaker amp XLR to the LA4 preamp. When I wanted a warmer tone I switched the amp XLR to the CODA 07x. After a while I realized I liked the LA4 better and sold the 07x.
However, it was a fun exercise.