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14 minutes ago, Eric Toline said:

Phantom stays on until you turn it off. It makes no sense to have phantom turn off for a disable then you have to turn it back on for the next time you have to record on that track.

I think it makes sense...

You could disable one track to unplug safely a phantom powered microphone.

Another plus, if phantom power turns off in a disabled track the consumption of your batteries would be optimized

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So...

I have already checked it with a volt meter.

And, yes. F8 stops feeding the microphone with the pantom power when you disable a track for recording.

the only thing is that it takes a while to go from 48v (in fact it has 46v) to 0v. When you enable the track it starts to phantom power again.

I think it has good reasons to do it. You can unplug the microphone safely and the power consumption of the batteries is optimized.

 

 

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On 5/11/2018 at 11:52 PM, Sprotnik said:

Hi. old topic but I have a doubt about the Zoom f8 that I can´t solve reading the manual or searching in the web (maybe I´m not searching the appropiate words...)

the question is:

when the phantom power in one track is activated, is it turned off automatically when you push the button of "disable for recording" of that track?

when you disable for recording one track it goes mute, but i don´t know if it stops giving phantom power to the microphone.

 

regards!

 

Why would you want this feature?

 

Edit: heh, saw the responses above now. 

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On 5/11/2018 at 10:08 AM, Sprotnik said:

So...

I have already checked it with a volt meter.

And, yes. F8 stops feeding the microphone with the pantom power when you disable a track for recording.

the only thing is that it takes a while to go from 48v (in fact it has 46v) to 0v. When you enable the track it starts to phantom power again.

I think it has good reasons to do it. You can unplug the microphone safely and the power consumption of the batteries is optimized.

 

 

I imagine that feature is to save on power consumption, the thought being that if the track is disabled, there is no need to have the 48V DC-DC converter on. Regarding the safety of plugging and unplugging a mic with phantom power turned on, there is no need for concern. 

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On 5/13/2018 at 10:33 AM, Glen Trew said:

 Regarding the safety of plugging and unplugging a mic with phantom power turned on, there is no need for concern. 

 

Like others, I've connected and disconnected phantom microphones many times without any harm or concern.

 

But there is an issue I think worth mentioning. With XLR connectors, there is no reason to be concerned. And, ordinarily there is no reason that a phantom microphone would be connected with anything else. However, when I was having a patch panel fabricated for my cart, I was advised to use XLR connections in that panel instead of the more usual phone connections. With the phone connections, it is possible to have a momentary short on the phantom power lines when inserting or removing the connector. That doesn't happen with XLR connectors with pins that keep the connections discrete.

 

David

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While microphones are fine being plugged and unplugged with phantom power on, other equipment may not be, such as wireless receivers. The SRa version of Lectro for example had that problem for a while, so it may be good practice to always turn phantom off when unplugging a mic

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On 5/16/2018 at 8:23 PM, David Waelder said:

 

Like others, I've connected and disconnected phantom microphones many times without any harm or concern.

 

But there is an issue I think worth mentioning. With XLR connectors, there is no reason to be concerned. And, ordinarily there is no reason that a phantom microphone would be connected with anything else. However, when I was having a patch panel fabricated for my cart, I was advised to use XLR connections in that panel instead of the more usual phone connections. With the phone connections, it is possible to have a momentary short on the phantom power lines when inserting or removing the connector. That doesn't happen with XLR connectors with pins that keep the connections discrete.

 

David

Hi David,

 

Proper TT phone plug patch panels (TT is the smaller than the original 1/4-inch plugs, standing for "Tiny Telephone") may cause a short of the phantom supply voltage, but this is of no concern because the phantom voltage always has two 6.8k in-line current limiting resistors that keep the maximum current of a 48V supply at or below 10mA. I have actual TT patch panels in carts I made in the late 80s, early 90s, and I've been hot patching 48V phantom with them for 30 years now with no problem. Of the 3000 recording studios in Nashville, the more sophisticated ones have TT patch panels that route 48V phantom to microphones.

 

This brings up a topic that deserves it's own thread about patch panels. Referring to XLR connector panels as "patch panels" is incorrect, as they are merely extension panels. "Patch Panel" refers to the ability to route through, interupt, not interupt, or connect. XLR panels can only connect, so, convenient as they are, they are not patch panels. That said, there are numerous advantages of patch panels, which will hopefully be realized again someday. 

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On 5/16/2018 at 7:23 PM, David Waelder said:

 

Like others, I've connected and disconnected phantom microphones many times without any harm or concern.

 

But there is an issue I think worth mentioning. With XLR connectors, there is no reason to be concerned. And, ordinarily there is no reason that a phantom microphone would be connected with anything else. However, when I was having a patch panel fabricated for my cart, I was advised to use XLR connections in that panel instead of the more usual phone connections. With the phone connections, it is possible to have a momentary short on the phantom power lines when inserting or removing the connector. That doesn't happen with XLR connectors with pins that keep the connections discrete.

 

David

 

2 hours ago, Glen Trew said:

Hi David,

 

Proper TT phone plug patch panels (TT is the smaller than the original 1/4-inch plugs, standing for "Tiny Telephone") may cause a short of the phantom supply voltage, but this is of no concern because the phantom voltage always has two 6.8k in-line current limiting resistors that keep the maximum current of a 48V supply at or below 10mA. I have actual TT patch panels in carts I made in the late 80s, early 90s, and I've been hot patching 48V phantom with them for 30 years now with no problem. Of the 3000 recording studios in Nashville, the more sophisticated ones have TT patch panels that route 48V phantom to microphones.

 

This brings up a topic that deserves it's own thread about patch panels. Referring to XLR connector panels as "patch panels" is incorrect, as they are merely extension panels. "Patch Panel" refers to the ability to route through, interupt, not interupt, or connect. XLR panels can only connect, so, convenient as they are, they are not patch panels. That said, there are numerous advantages of patch panels, which will hopefully be realized again someday. 

 

Untitled 8.png

 

patchbay.png

 

 

 

Also see:

 

https://www.lectrosonics.com/Support/component/com_fsf/Itemid,714/tag,Wireless, 48, phantom power, damage, receiver/view,faq/#

 

Untitled 12.png

 

 

Untitled 10.png

 

 

https://secure.aes.org/forum/pubs/journal/?ID=18

 

Untitled 11.png

 

http://www.thatcorp.com/datashts/AES7909_48V_Phantom_Menace_Returns.pdf

 

aes.png

 

 

 

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37 minutes ago, mono said:

 

Just to elaborate on my previous post then, regarding the phantom power and Lectro units: 

I had two units, one damaged by myself and one damaged by a colleague, and we both had left phantom power engaged in hectic situations. And in both cases the output stage got damaged in that it became very very quiet. I sent both to the Lectro distributor in Germany, Ambient recording, and they confirmed the issue and the *likely* cause and they repaired and definitely invoiced something. ...

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On 5/16/2018 at 8:30 PM, Constantin said:

While microphones are fine being plugged and unplugged with phantom power on, other equipment may not be, such as wireless receivers. The SRa version of Lectro for example had that problem for a while, so it may be good practice to always turn phantom off when unplugging a mic

 

The original SR used (new to us) 0402 size surface mount resistors in the output circuits. They were rated at 1/20 of a Watt and should have been fine. Then we started getting damaged units from the field (nothing like reality) and we (I) were flummoxed as to why the output resistors were failing.  All fault condition scenarios were accounted for and the resistors should not have failed. Further, this was an output stage topology that we had used for years. Once the resistors blew open, the rest of the output circuitry blew also. After some more units came in with the same failures, I decided reality owes us no explanations; it just is. The units were modified with 1/8 Watt 0805 parts and the problems ceased. I still don't understand what was happening. But resistors are very cheap and the problem went away. Incidentally, this was (is) an extended warranty repair.  It should have been done at no charge.

Best Regards,

Larry Fisher

p.s. It's still good practice to turn phantom power off when connecting to non mic audio circuits.

protection 

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Thank you all (Glen, Mono, Constantine, Larry F) for the education.

 

It would seem that the issue is a bit more complex than I had realized. 

 

My take away from all of this is that:

 

1. Damage to a microphone (as distinct from damage to other components) from connection to phantom power is most unlikely  because there is protection built into the circuit.

2. Notwithstanding this precaution, the real world sometimes presents unwelcome surprises. 

3. The use of XLR connectors may reduce the likelihood of a momentary short but it is not an absolute protection. Momentary shorts can happen even with XLR connections.

 

Is this a fair summary?

 

David

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Re p48 and non-mic circuits: it used to be that gear like mixers etc could be damaged by being connected to old school betacam style camera audio inputs if the p48 was on.  This didn't happen to me with robustly xformer protected gear like Shure FP mixers, more with electronically balanced gear (mixers, signal processing).  Whose outputs I quickly learned to protect with trafos.....

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17 hours ago, Philip Perkins said:

Re p48 and non-mic circuits: it used to be that gear like mixers etc could be damaged by being connected to old school betacam style camera audio inputs if the p48 was on.  This didn't happen to me with robustly xformer protected gear like Shure FP mixers, more with electronically balanced gear (mixers, signal processing).  Whose outputs I quickly learned to protect with trafos.....

Yes and to get the topic back to the Zoom's, the F4 and I believe F8 too, are known for that, in protected XLR outputs. I believe there is an official warning for that on Zoom's website.

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The F8 failed when it got cold. I dont remember how cold it was, but maybe around -5c? I would not turn on again before it was warm enough.

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