DL1608 destroying my Mac Mini(s)

[ILC Saratoga]

Ok, here's the deal, we use the DL1608...duh..we record off of it using a Mac mini and also play back with the slides/video in Keynote.  We're using phantom power to the mic's which means that it's going to Mac Mini(output/headphone to DL 1608). 

It worked great for 3 months then BOOM fried the sound portion of the logic board.

Checked cables which are hardly ever moved, everything good.  No shorts everything else as it should be.

Just had Apple put in a new logic board and tested with a head set, worked fine.  As soon as I plugged in the DL1608 poof, bye bye sound.

Configuration is Headphone jack (out) to XLR input channel 16.  Aux 2 to Mac Mini Input.

I'm completely open to suggestions.  Well most of them that is.

[RoadRanger]

Configuration is Headphone jack (out) to XLR input channel 16.  Aux 2 to Mac Mini Input.

Very wrong, you should use the TRS "line input" jack on channel 16 that has no phantom on it - or an isolating DI - for any non-microphone input source. You could have just as easily fried a keyboard, acoustic guitar, submixer, or an amp DI output. Unfortunately this is a common problem amongst non-pro users . Expensive education for you but now you know .

[Wynnd]

Headphone out to channel 16 in?   ARE YOU NUTS?   That's an amplifier output.  Never intended to go to any input of any type.  ONLY USE THE HEADPHONE OUTPUT DIRECTLY TO SPEAKERS!!!!!  (Headphones are speakers.)   Now, phantom power shouldn't be on any outputs.  It's only on the XLR inputs 1-16.  It isn't on any 1/4" phone plug inputs.  (Note: the dual inputs have phantom power on the XLR and not on the 1/4" inputs.)   

Quick question?  What microphones are you using that require phantom power?  Are you guessing or do you actually know that you are using "condenser" microphones.  (Most are dynamic and phantom power has no effect on those.)   If you're using a full set of "drum mics", the overhead mics are likely to be condenser microphones. (frequently, but not always.) 

[RoadRanger]

Headphone out to channel 16 in?   ARE YOU NUTS?   That's an amplifier output.  Never intended to go to any input of any type.

Incorrect - most of us have used a headphone output into a mixer before. I have a 1/8" stereo plug to twin 1/4" mono plugs cable I often use with the channels 15 and 16 line inputs (TRS). Works a treat !

[Wynnd]

Just because it worked for you, doesn't make it a good thing to do.  I never run amplifiers into inputs.  NEVER NEVER NEVER!!!!!!   If you fry something doing that, you probably deserved it.  I don't drive my car off cliffs either.  They aren't designed to be used that way. 

Misusing equipment and then complaining about it breaking should be illegal.

[RoadRanger]

Just because it worked for you, doesn't make it a good thing to do.  I never run amplifiers into inputs.  NEVER NEVER NEVER!!!!!!   If you fry something doing that, you probably deserved it.  I don't drive my car off cliffs either.  They aren't designed to be used that way. Misusing equipment and then complaining about it breaking should be illegal.

The headphone output on a PC or iDevice is also the line out. 1/8" stereo to dual RCA plug cables are extremely common. And all active devices have amplifiers on their line outputs, including keyboards, pedals, CD players, etc. You may very well be the only one on this board who doesn't commonly use 1/8" stereo headphone jacks as line outs .

In this case it was the 48V phantom power that fried the output. As a general rule of thumb never feed an unbalanced output into an XLR input on a mixer without transformer isolation - and even devices with XLR outputs can be damaged by phantom (or possibly powered by it ).

OTOH if the run is long (or the device is not on the same power as the mixer) I'll use a couple of XLR cables and and 1:1 isolation transformers between the mixer and the 18" splitout cable.
http://artproaudio.com/artcessories/audio_solutions/product/dti/

[WK154]

Headphone out to channel 16 in?   ARE YOU NUTS?   That's an amplifier output.  Never intended to go to any input of any type.  ONLY USE THE HEADPHONE OUTPUT DIRECTLY TO SPEAKERS!!!!!  (Headphones are speakers.)   Now, phantom power shouldn't be on any outputs.  It's only on the XLR inputs 1-16.  It isn't on any 1/4" phone plug inputs.  (Note: the dual inputs have phantom power on the XLR and not on the 1/4" inputs.)   

Quick question?  What microphones are you using that require phantom power?  Are you guessing or do you actually know that you are using "condenser" microphones.  (Most are dynamic and phantom power has no effect on those.)   If you're using a full set of "drum mics", the overhead mics are likely to be condenser microphones. (frequently, but not always.)

This is where specs come in handy. The headphone output of the iPad is somewhere less than 24 ohms down to about 10 ohms (for the Mac mini, Apple doesn't really spec this 3.5mm connector) this is more than adequate to drive the line in on the DL (TRS connector only or no Phantom power XLR) at 30K ohms for line input and 3K ohms for mic input. 48 V on an output that would typically handle 2 V does kill it as you found out.

[RoadRanger]

BTW I'm a charter member of the global phantom hater's club  . But even with individual channel phantom switching skipping the isolation when needed puts you one "oops"away from disaster.

[Wynnd]

On a Mac that is true.  The Mac audio output is DESIGNED to put out amplifier level to headphones, Line level to amps and even light for fiber cable. (Surround Sound digital on the fiber.)  DESIGNED for all that. (And on mine, also a microphone input in the same connector.)   I'm not interested in suggested off product uses.  I don't use Microphones as speakers or speakers as microphones.  (And dynamic microphone parts are the same type of parts as speakers have.  Coil, Magnet and diaphragm.)

[RoadRanger]

On a Mac that is true.  The Mac audio output is DESIGNED to put out amplifier level to headphones, Line level to amps

So're the PC and iDevices .

[Wynnd]

None of the PC's I've ever owned were, but new ones might.  Only have one now and mostly use it for playing games.  (Windows 7, quad core processor.  It's been here for a while.)  And yes, I did know about the ios devices.  Have 3 iphones in the house, 2 ipads.  Apple products, I expected it of them.  (Don't know about fiber with them.  I don't really have a fiber inputed device in the house.) 

[WK154]

None of the PC's I've ever owned were, but new ones might.  Only have one now and mostly use it for playing games.  (Windows 7, quad core processor.  It's been here for a while.)  And yes, I did know about the ios devices.  Have 3 iphones in the house, 2 ipads.  Apple products, I expected it of them.  (Don't know about fiber with them.  I don't really have a fiber inputed device in the house.)

ALL headphone outputs will drive a line/mic input.

[Wynnd]

That's a change.  I've been dealing with PCs since 1984.  Don't expect them to never change, but after years of Windows issues and problems and pains, I moved over to Macs and have never regretted it.  I was a Network/PC tech.  (CNA A+ Novell certifications.)  I don't do that anymore.  (At home, I'm still the tech.)  So it's good to see other manufacturers catching up.  And passing Apple on the touch screen.  Already I reach up and touch the screen out of habit with my ipads and iphone.  My next MacBook will have to have a touch screen.   Meantime, I'm still quite happy with my 5 year old MacBook.  Hopefully Apple will make the jump within the next few years.  (Though I'm sure I could live with this computer for another 5 years with one battery replacement.)

[sam.spoons]

I've just reread the start of this thread and the OP ILC Saratoga says he connects the headphone output to CH16 XLR input. There are several ways to do this, nearly all wrong (even some which employ a DI box). I'd be interested to know precisely what type of lead/adapter was used?

[Keyboard Magic]

Just because it worked for you, doesn't make it a good thing to do.  I never run amplifiers into inputs.  NEVER NEVER NEVER!!!!!!   If you fry something doing that, you probably deserved it.  I don't drive my car off cliffs either.  They aren't designed to be used that way. Misusing equipment and then complaining about it breaking should be illegal.

The headphone output on a PC or iDevice is also the line out. 1/8" stereo to dual RCA plug cables are extremely common. And all active devices have amplifiers on their line outputs, including keyboards, pedals, CD players, etc. You may very well be the only one on this board who doesn't commonly use 1/8" stereo headphone jacks as line outs .

In this case it was the 48V phantom power that fried the output. As a general rule of thumb never feed an unbalanced output into an XLR input on a mixer without transformer isolation - and even devices with XLR outputs can be damaged by phantom (or possibly powered by it ).

OTOH if the run is long (or the device is not on the same power as the mixer) I'll use a couple of XLR cables and and 1:1 isolation transformers between the mixer and the 18" splitout cable.
http://artproaudio.com/artcessories/audio_solutions/product/dti/

Can't actually remember (old age) are the combo jacks on the DL1608 phantom enabled? I've been doing what you do connecting laptops/iPads/pods to 15/16 on the DL for a while and no issues ever. And I've had to run with phantom enabled while doing this.  I do use a dual DI box and mic cables for long runs though, always. This is the DI I use:

https://www.long-mcquade.com/840/Pro_Audio_Recording/Mic_Preamps_DI_Boxes/ART_Pro_Audio/Dual_Passive_Direct_Box.htm