How will the Delta 15 sound without a zobel?

It makes sense that nothing between amp and driver is technically best. I do wonder though, will this compromise the Pi sound with respect to tonal balance?

Adcom amps thump at power up. will this thrash the compression driver without a cap inline?

I do not doubt what Wayne says on this subject, but I also know a lot of what makes a thing "best" is situation dependant.