Bigbri5050

I have a great Fender Rumble 100 amp. However, the d.i. signal vanishes when you turn down the amplifier volume. I need the signal to remain for the mixing desk even when I turn my amp down. In this case the p.a. monitors and IEM's give me the sound I need. Do you know of any amps that will do this? I've tried asking the manufacturers but not sure the front-line staff will understand the issue.