AER Compact 60 DI-Out Question

[mchalebk]

I usually only sing with my church choir. However, I recently played guitar during Mass and brought my AER Compact 60 as a monitor. I ran the line out to the sound system.

When connecting to the mixer, I originally planned to use the XLR DI-Out. That would allow me to tweak the master volume on the amp without affecting the feed to the sound system. However, I wasn't sure if it was okay to connect the DI-Out to an XLR input with phantom power on the board. My initial assumption is that it should be fine. However, to be safe, I used the 1/4" Line Out, which worked just fine.

So, can anyone tell me if the XLR DI-Out on the Compact 60 can be safely plugged into an input with phantom power on?

[JoeCharter]

Not sure whether it's ok or not but I did what you described plenty of times.

[Bobby1note]

Phantom power should be switched off at the console, until the connection has been made,,, and only then should you switch phantom power back on. You will see this warning in virtually every mixers' owners' manual.

[mchalebk]

Originally Posted by Bobby1note

Phantom power should be switched off at the console, until the connection has been made,,, and only then should you switch phantom power back on. You will see this warning in virtually every mixers' owners' manual.

This is true, at least when connecting condenser mics: you need to turn phantom power off prior to making the connection. However, maybe I didn't make my question clear. I'm not asking if it's okay to connect the DI-Out while phantom power is on (though I guess that would be a good question to ask, too). What I'd like to know is if it's okay to have the DI-Out connected to a mixer that has phantom power applied (it can be turned off, if need be, while connecting). Not every device out there can have phantom power applied safely.

[Bobby1note]

Originally Posted by mchalebk

This is true, at least when connecting condenser mics: you need to turn phantom power off prior to making the connection. However, maybe I didn't make my question clear. I'm not asking if it's okay to connect the DI-Out while phantom power is on (though I guess that would be a good question to ask, too). What I'd like to know is if it's okay to have the DI-Out connected to a mixer that has phantom power applied (it can be turned off, if need be, while connecting). Not every device out there can have phantom power applied safely.

Send AER customer service a message, just to be 100% sure. I would seriously doubt that this would present a problem; especially with a component of this calibre.

No matter what though, I'd at least turn off phantom-power, while making the connection. That's especially easy to do if your mixer has independent phantom-power switches on every channel (MixWiz3 for example).

[mchalebk]

Found this is an Allen & Heath mixer manual:

...but care is needed to ensure that 48v is not switched on if an xlr is used to input a signal from an electronic circuit (ie. Another mixer or keyboard).

Certainly makes it seem like a bad idea, but I could still see that some gear may be designed in such a way that this isn't a problem. If I can't get any definitive responses here, I will try contacting AER. I know this is a popular amp, though, and I figured there would be people here who are in the know.

[MODELL]

FWIW, my small acoustic trio has a powered mixer with only a "master" phantom power button meaning all channels or none. We do need it for one input, so it does get turned on. The other inputs include DI from Markbass amp, passive DI box and other dynamic microphones. We have never had an issue with any of the non-phantom powered devices. I think you will be fine to do this from the DI on your amp.

[mchalebk]

I appreciate all the responses. Having read at least one mixer manual that indicates this is a bad idea, I think it might be time to contact AER and see what they have to say.

[mchalebk]

I bought my amp back in 2006 or 2007, so I don't believe it's the new 60/2 version. I did just notice the following in the manual for the 60/2 (this was not in the manual for my amp):

Examples of devices that may be damaged by incorrect application of phantom power include: Low-cost dynamic microphones with a mono jackplug (unbalanced signal) that were fitted afterwards with an XLR connector. Audio devices with a balanced XLR output (e.g. DIboxes, effects devices, instrument preamps with a DI output etc.) which are not protected against phantom power applied to their XLR output. (The DI connectors on AER products are protected against applied phantom power.)

This makes it sound like I should be okay. However, since mine is a somewhat older model, I send an e-mail to AER to try to verify this.

One thing this has made clear, though, is that it is not a given that an XLR DI output is inherently protected against applied phantom power and we should be careful when connecting these various devices.

[mchalebk]

I contacted AER. It turns out that I actually have a Compact 60/2 model, which I didn't realize. AER confirmed that the 60/2 models are protected from applied phantom power. They didn't explicitly state that the earlier models would not be protected, but it was kind of implied that was the case.

Bottom line (for me): I can plug this into a mixer that has phantom power enabled (though I should make sure phantom power is off when making connection).

Bottom line (general): we shouldn't assume it is okay to connect DI outputs to inputs that will have phantom power applied; not all gear can handle it.

[El Conquistador]

Originally Posted by mchalebk

Bottom line (general): we shouldn't assume it is okay to connect DI outputs to inputs that will have phantom power applied; not all gear can handle it.

This kind of information is the best reason for a forum like this. Thanks!

Steve