Help! I may have inadvertently damaged my DP24 SD

[Sippy Sound]

I am not only new to this forum but new to the DP24 as well. I have owned it for approximately 18 months, and while I have been recording with it with no problem at all (it's been a great addition - replacing my old Fostex VF160), I am not familiar with it, but enough to perform basic recordings. Of course, all the videos from Phil Tipping have been a great tool as well.

I have a project that is nearly finished and have only the vocals to add. I typically use one of my dynamic mics for the vocals because my condenser mic isn't all that great. I suppose it was on a whim, but I wanted to do a side-by-side comparison of the two mics and assigned each mic to a track; the dynamic on track 7 (g) and the condenser on track 8 (h). My condenser requires phantom power, so I made sure to turn ON the phantom power switch. Both mics were armed and after I did a quick recording I concluded that the dynamic just sounded better. I turned OFF the phantom power and removed the condenser mic before going on about "business as usual" in the recording - no problem (except the vocals were not that great and would have to be redone later). Enter last night.

It had been about a week since I returned to my project (I wanted to redo the vocals) and I went directly to my dynamic mic, assigning it to track 8 (h), and when I armed it (same as I have done with anything that I use on any other track), I get nothing. No sound, no reading on the meter - nothing from track 8. All the other tracks that I have recorded still playback with no problem. I then tried the mic on another track. Same thing. I tried three different tracks - nothing. Thinking maybe there might be an issue with track 8, I connected my synth to it, and it worked fine.

So I grabbed a different dynamic mic, switched out the cable - same thing, no sound, no meter. Finally, I tried my condenser mic (turning ON the phantom power, etc), and it worked. But when I tried the dynamic mic again (turning OFF phantom power) I still had nothing.

I even tried resetting the unit (doing the initializing), and nothing.

Did I damage the unit when I had phantom power turned on (intended for the condenser mic in track 8) and also had my dynamic mic in track 7? I'm thinking I should have connected my dynamic into another track (1-4) considering that phantom power was (I'm guessing) active on tracks 5-8?

I know this is a huge rambling of what could have been described in one sentence, but I'm so frustrated at the idea that I may have damaged the unit on what now seems like a common-sense deduction.

Thanks for any and all suggestions.

 

[David Porter]

Have you got the input trim turned up appropriately for that dynamic?

If I recall correctly - I have to have the trim up to at least 2-3 o'clock for the SM57.

 

[Mark Richards]

Did I damage the unit when I had phantom power turned on (intended for the condenser mic in track 8) and also had my dynamic mic in track 7? I'm thinking I should have connected my dynamic into another track (1-4) considering that phantom power was (I'm guessing) active on tracks 5-8?

Yeah, you would have been better served using Inputs A~D for the dynamic mic. Just for peace of mind.

But generally speaking, phantom power won't cause any damage when a dynamic mic is connected with an XLR cable (the exception being with ribbon mics). The cabling must be XLR, and must be wired correctly for balanced operation.

 

[Sippy Sound]

David: Thanks for replying. Yah, I have played with the trim - you're absolutely right, it does have to be, and typically is close to 3 o'clock. However, that said, I checked again, and still nothing.

Mark: Thanks for the "peace of mind"...

 

[David Porter]

Hmmmm.... only thing I can think of is to go back to the drawing board and use multiple mics with multiple cables - and into multiple inputs.... and look for what is *common*.

By what you've said so far - I'm doubting you've damaged anything in the DP.

 

[Mark Richards]

Just to be clear, are these the steps you performed, in sequence.

1. Set Input H guitar switch OFF
2. Set Phantom Power OFF
3. Connect dynamic mic with XLR cable to Input H
4. Assign Input H to Track 8.
5. Turn Input H Trim Knob full clockwise
6. Press Track 8 REC button (record ready)

RESULT: No signal from dynamic mic appears on Track 8 meter. (Does the mic have an on/off switch?)

Next Test:

• Replace dynamic mic with condenser mic using same XLR cable and repeat with Phantom Power ON.

RESULT: Signal on Track 8 meter.

Next Test:

• Reconnect the same dynamic mic using the same XLR cable.
• Repeat steps 2~6, but instead using Input A Assigned to Track 1.

What is the result now?

 

[Sippy Sound]

Mark: So, I went through the entire process again, just as you described, and I experienced the same result: condenser mic works, but the dynamic did not.

HOWEVER... for kicks and giggles (and don’t know why I didn’t think of this before, other than just blinded with initial frustration), I dug around for one of my other dynamic mics - and holy crap - it works! So I’m guessing that I must have dried out something in the dynamic mic I was using, because everything is working as normal on every input!

Thank you for all the responses and guide, I really appreciate the time you guys have taken to respond to this. Very grateful

 

[-mjk-]

That mic is toast (which was my first thought). However, the phantom power should not have harmed it. What model is the dynamic?

 

[Sippy Sound]

It’s a Beyerdynamic TGX-58

 

[-mjk-]

Thanks @Sippy Sound. That is a rugged stage mic and phantom power wouldn't faze it, unless you were using an unbalanced cable, where the phantom power supply would flow through the pickup coil to ground and possibly burn it out. As long as you were using a standard XLR cable, nothing bad should have happened.

At this point, I would do 2 things: 1: Use a DMM and look across the capsule for an open coil. 2: Check the On/Off switch for function. If the coil is ok but the switch is bad, I would just jumper across the switch.

Edit: I forgot to mention that there probably is an isolation transformer between the microphone's XLR output connector and the capsule. I didn't specifically look at the diagram for that microphone, but the SM58 has one. Transformers block DC so isolation transformers protect dynamic mics from those issues.

 

[Sippy Sound]

Thanks @-mjk-
I appreciate the info. Yah, I’m using standard XLR cables, and the two other dynamic mics I have are both a Beyerdynamic TGX-58. So far so good on them all except for the one that is likely fried. I’ll have it checked out, but I’m just happy my DP wasn’t damaged and I’m “back in business”!