DI Preamp 48v phantom power worries

Javabean

Hi all,

I have a question about phantom power.

I have a gig coming up where someone else (not me) is in charge of the mix and the desk.

My acoustic goes into my Boss AD-10 preamp which has two XLR outs and two line outs.  I'll take a line out to my acoustic amp for backline and two XLRs to the mixer.

Question :-- If the sound guy turns on 48v phantom power to my (XLR) channels, will it kill my Boss AD-10?

I have the option of taking a balanced line (1/4" TRS) out of my acoustic amp and putting that into a 'normal' DI which expects and is powered from 48v at the desk.

At the moment, this seems to be a safer option as I'm not risking the Boss, but it seems a bit of a faff to have two DI's.

Any thoughts?

Thank you
David

John_P

I’d be very surprised if it was an issue - plenty of preamp pedals can be powered via phantom power so even if the boss can’t, they should be at aware that it could be connected with it turned on.  
If you’re worried though just mention it to the engineer as you’re setting up to double check it’s turned off - my default is to have it switched off on all channels unless I need it but I would appreciate a heads up about any issue when I’m setting up a band. 

ESBlonde

No. Devices designed with XLR outs are intended to connect to desks, often cheap desks have global phantom power, so all channels not selectable. Phantom power goes up both the hot cores and back on the screen, by isolating the screen it cuts the circuit. The differential amp in the Mic input on the desk can ignore equal voltage In both pins. Few budget desks have true 48v these days, more like 9v or 18v,  48v is the leftover from the first use of valve mics in a studio that fed off the lighting circuit built in of...48v. This then became the standard for decades.

maltingsaudio

There won’t be a problem, see many of these on stages. Interestingly just skimmed the manual for it and no mention of phantom, would have thought there would be if only to say pedal couldn’t be run from it.

Javabean

Thank you all for your replies.  I'm confident enough now give the Boss AD-10 a try with phantom power and hope not to see what a friend of mine calls 'the magic smoke'.  I will of course do this well before the gig in question, just in case.
Incidentally, I have looked at the manuals for the Baggs Venue DI, Fishman's Platinum Pro and the Headway EDB-2.  Only the Headway mentions a 48v feed inasmuch as to say that it cannot be powered by it, but it will not harm the unit.

steamabacus

Being as it's Boss, I'd be very surprised if it hasn't been designed to handle phantom power, as people above have said.

However, if you're in any way worried or if you have other pieces of kit you may have similar worries about, a transformer isolator like the one from Orchid here will give you 100% peace of mind. Also useful for plugging things with no proper grounding like laptops into a PA.

markslade07

Trust you to start a thread about 48 volt phantom power!