Just got my Aguilar DB750. I didn't realize it 'only' comes with speakon output jacks for the speakers so I wasn't prepared and didn't have a cord. The blue diagnostic led kept blinking when I powered it on for the 1st time and never stopped. I suspected it may need to have the speaker connected when powering up, but no where in the manual does it state this as if it were critical. Well, I took it to practice to try it out for the 1st time as there was a speakon cord there to use. It still kept flashing the blue led for several attempts (waiting 30-60- seconds) then one time after fiddling with the mute switch, it decided to pass. This is a concern since I'm used to lights coming on immediately when I flip a switch. None of my other amps have required preconnected speakers . I've had other tube amps before that need to warm up for a 'few' seconds before coming alive. This seems like an issue to me. I practiced for several hours tonite and it's everything I've read about on TB. but I'm concerned about reliability at this point. Does anyone elses DB750 work everytime after it's brief diagnostic check or has it gone on for longer than a minute while blinking? This is a brand new unit.