RRabbi
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Is it possible to send Phantom Power via TRS connectors?
Hi There,
I had a local sound specialist company build me a wall panel for my home studio. The panel had 12 XLR connectors on it (for mic'ing drums, guitars, vocals, etc...) but the snake that came out of the wall on the control room side only had 12 TRS plugs? I believe they were balanced, low impedance, tip ring sleeve, blah blah blah, but I quickly found out that I couldn't send phantom power from my board thru those cables out to the wall panel and mics.
The company at first tried to tell me that you CAN send phantom power thru TRS connectors, and that I couldn't because my board wasn't sending phantom power thru the quarter inch inputs.
So, my questions are:
1. Is it ever possible to send phantom power thru TRS connectors, or do you ALWAYS need XLR connectors to do this.
2. Have you ever heard of a mixer (mine is a Motu 828 MkII, and two ADA8000's, by the way) that can send Phantom power via the quarter inch inputs?
Thanks...
Dave
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ohhey
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/20 06:43:22
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ORIGINAL: RRabbi
Hi There,
I had a local sound specialist company build me a wall panel for my home studio. The panel had 12 XLR connectors on it (for mic'ing drums, guitars, vocals, etc...) but the snake that came out of the wall on the control room side only had 12 TRS plugs? I believe they were balanced, low impedance, tip ring sleeve, blah blah blah, but I quickly found out that I couldn't send phantom power from my board thru those cables out to the wall panel and mics.
The company at first tried to tell me that you CAN send phantom power thru TRS connectors, and that I couldn't because my board wasn't sending phantom power thru the quarter inch inputs.
So, my questions are:
1. Is it ever possible to send phantom power thru TRS connectors, or do you ALWAYS need XLR connectors to do this.
2. Have you ever heard of a mixer (mine is a Motu 828 MkII, and two ADA8000's, by the way) that can send Phantom power via the quarter inch inputs?
Thanks...
Dave
Devices will not have phantom power on 1/4" TRS because the contacts don't mate at the same time and can short as you plug it in. So, no as a rule you never have phantom power on TRS connectors and you don't want to have it on a 1/4" TRS patch bay either. That being said it would "work" if you converted back to XLR as long as all three contacts are wired through and not shorted but again you don't want to do this. If someone tried to unplug one of the converters while it was on it would short.
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MandolinPicker
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/20 11:08:13
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I'm a little confused, for I thought you could send phantom power through a TRS connection. When I look at the wiring diagram, I see the following on a TRS connection; Tip - Positive/Hot Ring - Negative/Cold Sleeve - Ground When I look at an XLR connection, I see the following; Pin 1 - Ground Pin 2 - Positive/Hot Pin 3 - Negative/Cold (Connection info on Wikipedia - http://en.wikipedia.org/wiki/Jack_plug for TRS and http://en.wikipedia.org/wiki/XLR_connector for XLR) Now I'll admit that I am no electrician, but if the wiring is the same, why can't phantom power be sent through a TRS connection?
The Mandolin Picker "Bless your hearts... and all your vital organs" - John Duffy "Got time to breath, got time for music!"- Briscoe Darling, Jr. Windows 8.1, Sonar Platinum (64-bit), AMD FX 6120 Six-Core, 10GB RAM
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Clydewinder
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/20 14:36:23
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theoretically you CAN, but whenever you plug in or remove a 1/4" TRS plug, there are moments where 2 or 3 of the contacts are shorted together as they slide through the jack terminals. this can damage the phantom power source. not recommended
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Joe Bravo
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/20 16:20:35
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"theoretically you CAN, but whenever you plug in or remove a 1/4" TRS plug, there are moments where 2 or 3 of the contacts are shorted together as they slide through the jack terminals. this can damage the phantom power source. not recommended"
Ah, that makes sense. I never thought about it before.
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Clydewinder
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/20 16:53:03
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yeah, that's the same reason they came out with those neat "speakon" plugs for loudspeakers... nonshorting.
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Joe Bravo
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/20 21:44:04
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MandolinPicker
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/21 01:04:55
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That would explain why I found the following on how to 'power up' a mic that uses phantom power; Safest Power Up Order
- Turn on Mixer with Microphone Disconnected
- Make Sure Phantom Power is Off
- Plug in Microphone
- Switch On Phantom Power
The Mandolin Picker "Bless your hearts... and all your vital organs" - John Duffy "Got time to breath, got time for music!"- Briscoe Darling, Jr. Windows 8.1, Sonar Platinum (64-bit), AMD FX 6120 Six-Core, 10GB RAM
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themidiroom
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/21 10:41:40
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I'm surprised a sound company would have wired the panel with TRS one one side unless you requested it.
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coldsteal2
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/21 23:09:45
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I had a surprize the other day when i pluged my Audio Technica Condencer vocal
mic into a mixer without the 48v switch turned on, i mean there was no power to
it but my mic worked perfectly? I then turned on the 48v phantom power
and only got a slight power increase.
very odd, now THATS Phantom power hahah
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RRabbi
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/23 06:24:14
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I had them rewire the connectors to be XLR... problem solved...
Yeah, I was surprised too :)
Works fine now...
Only thing i'm wondering about now, is they wired up two MIDI connectors for the wall panel, but there's only 3 wires in the cable, but 5 pins on the MIDI connector? That kinda confuses me too, but they said that when the cut the MIDI cables that they had there was only 3 wires...
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RRabbi
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RE: Is it possible to send Phantom Power via TRS connectors?
2007/02/23 06:25:29
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I had them rewire the connectors to be XLR... problem solved... Yeah, I was surprised too :) Works fine now... Only thing i'm wondering about now, is they wired up two MIDI connectors for the wall panel, but there's only 3 wires in the cable, but 5 pins on the MIDI connector? That kinda confused me too, but they said that when the cut the MIDI cables that they had there was only 3 wires... Found THIS tho: http://colomar.com/Shavano/midi_cable.html Makes sense now...
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