pncola

Hi. I bought a pre owned HD400 last month and I don't have too much knowledge about line 6 product. My HD400 takes about 2, 3 minutes warm up time to come out the full sound after turn on. After that it works fine. No need to wait again for the warm up if I turn off and turn on again. Is it common for every HD400 to wait 2, 3 minutes at the first time power on. Or is it error? Please advise. Thanks.