Phantom Power: Difference between revisions - Bose Portable PA Knowledge

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=== Will Phantom Power Damage Dynamic Microphones ===

:Phantom power supplies have current limiting which will prevent damage to a dynamic microphone even if it is shorted or miswired. In general, balanced dynamic microphones can be connected to phantom powered mixer inputs with no problem.

::Source: [http://www.shure.com/americas/support/find-an-answer/what-is-phantom-power What is Phantom Power, Shure.com]

:As long as your mic cables are all wired properly (balanced, with the correct pin connections) and well made, and you are using decent XLRs everywhere — and all your microphones are modern — there is no problem at all.

::Source: [https://www.soundonsound.com/sound-advice/q-phantom-power-on-dynamics Phantom power on Dynamics, Sound on Sound]

== Phantom Power Supplied by Bose Systems ==

~~On the {{Classic}} / {{Model I}} the Power Stand supplies 24 volts for Phantom Power.<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|~~Phantom Power ~~in Model I FAQ]]</ref>~~

=== Phantom Power Available ===

~~The~~ {{T1}} ~~provides~~ 48 volts ~~for~~ Phantom Power.<ref>[[~~L1®_T1_ToneMatch®_Audio_Engine_~~/_FAQ#~~Do_the_mic_inputs_of_the_ToneMatch_audio_engine_have_phantom_power~~.3F|Phantom Power in ~~T1®~~ FAQ]]</ref>

Phantom Power is available on

* {{ToneMatch Mixers}} and {{T1}} 48 volts<ref>[[L1®_T1_ToneMatch®_Audio_Engine_/_FAQ#Do_the_mic_inputs_of_the_ToneMatch_audio_engine_have_phantom_power.3F|Phantom Power in T1® FAQ]]</ref><br>When you turn on the Phantom power, it is available on all XLR inputs. It cannot be turned on/off on individual channels.

** {{T1}} channels 1, 2, 3

** {{T4S}} channels 1, 2, 3, 4

** {{T8S}} channels 1, 2, 3, 4, 5, 6, 7, 8

* {{Model I}}<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|Phantom Power in Model I FAQ]]</ref>

** channels 1 and 2 turned on/off individually

* {{Classic}}<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|Phantom Power in Model I FAQ]]</ref>

** channels 1 and 2 turned on/off individually

~~The~~ {{~~ToneMatch Mixers~~}} ~~provide 48~~ volts for Phantom Power.

Phantom Power is available on

* {{Classic}} / {{Model I}} the Power Stand supplies 24 volts for Phantom Power.<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|Phantom Power in Model I FAQ]]</ref>

~~=== Will Phantom Power Damage Dynamic Microphones ===~~

:Phantom power supplies have current limiting which will prevent damage to a dynamic microphone even if it is shorted or miswired. In general, balanced dynamic microphones can be connected to phantom powered mixer inputs with no problem.

~~Source: [http://www~~.~~shure~~.~~com/americas/support/find-an-answer/what-~~is-phantom~~-power Shure.com]~~

==== Current Limiting ====

Bose Phantom power supplies have current limiting which will prevent damage to the Bose device if the connected device attempts to draw too much current.

==== Turn Down Master Volume Before Turning on Phantom Power ====

; Please turn down the Master Volume control before turning on phantom power

This will avoid noise being sent out to the powered loudspeakers when you turn on the power.

=== No Phantom Power ===

There is no phantom available on

* {{Compact}}

* {{Model 1S}}

* {{Model II}}

* {{F1}}

* {{S1}}

== Phantom Power Connected to Bose Systems ==

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You may want to connect your Bose Portable PA to an external system using the Line Out. All of the Line Outputs are line-level, balanced outputs. On the {{T1}}, T4S, T8S, {{Compact}}, the outputs are 1/4 inch (6.3mm). On the T8S, there are also XLR Outputs.

=== Will Phantom Power Damage Bose Outputs? ===

;Will phantom power provided by the external system damage the Bose Portable PA system?

The outputs of Bose Portable PA equipment have circuitry to protect them in case phantom power is turned on in the external system.

=== 24V volt Phantom Power ===

From Hilmar-at-Bose

That is a somewhat difficult topic. We certainly have tried a KMS105 for live and even for recording with our 24V phantom supply and didn't find any problems. Then again, everybody's ears and taste is a little different, so I can't claim that there really isn't any difference.

Going through the Alesis might also change things a little, so it's hard to do an exact apples-to-apples comparison.

From a technical stand-point, it's difficult for me to believe that there are any issues. I haven't taken a KMS 105 apart yet (they ain't cheap !) but most Neuman mics use an internal DC to DC converter and polarize at 200V or so. If any, that should work better with a "proper" 24 V supply because it can provide nearly twice the overall power of a standard 48V supply. Getting more useable DC power was actually one of the reasons why the 24V standard was suggested.

Different microphones do different things with Phantom Power but it's not only the voltage that matters but also the current. The original 48V/6.8kOhm standard was optimized for microphones that needed external polarization and therefore high voltage but nearly no current at all. But this type of microphone is exceedingly rare these days and the phantom power is used either to drive an internal pre-amp or to run an internal voltage-converter or stabilizer. For both cases a supply with lower voltage and higher current (and more overall power) is actually better and hence the 24V/1.2kOhm standard was derived.

I hope I don't bore everybody to death with some math, but let's look at the example of the KMS105. I believe that at nominal 48 V the mic draws about 4mA. That current also goes through the internal 6.8k Ohm resistor of the phantom power supply and leads to voltage "sag". If we use Ohm's law we find that the internal effective resistance of the microphone is about 5 kOhms and that the voltage at the microphone terminals is only 20 V. All the rest is lost inside the supply. If you attach the same microphone to 24V/1.2kOhm supply the voltage sag is much less and the voltage at the microphone terminals comes out to be 19V. It's hard for me to believe that this 1 V difference should make any apprectiable difference in the mics performance.

For an even more power hungry microphone that draws 5mA, the 24V/1.2kOhm supply will actually provide 3 Volts MORE (17V vs. 14V) at the microphone terminals. Sounds a little counterintuitive, but is actually true.

Of course, in the end you have to be the judge of what sounds best to you ears.

Hope that helps

Hilmar

Source: [https://www.bosepro.community/g/portable/topic/phantom-power-4?reply=18197182791945827#18197182791945827 Phantom Power discussion in the Bose Portable PA Community]

==Questions==

If you have questions about this article, please post a message in [https://www.bosepro.community/g/portable/topic/phantom-power-11 Phantom Power Discussion in the Bose Portable PA Community]

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@@ Line 15: / Line 15: @@
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+=== Will Phantom Power Damage Dynamic Microphones ===
+:Phantom power supplies have current limiting which will prevent damage to a dynamic microphone even if it is shorted or miswired. In general, balanced dynamic microphones can be connected to phantom powered mixer inputs with no problem.
+::Source: [http://www.shure.com/americas/support/find-an-answer/what-is-phantom-power What is Phantom Power, Shure.com]
+:As long as your mic cables are all wired properly (balanced, with the correct pin connections) and well made, and you are using decent XLRs everywhere — and all your microphones are modern — there is no problem at all.
+::Source: [https://www.soundonsound.com/sound-advice/q-phantom-power-on-dynamics Phantom power on Dynamics, Sound on Sound]
 == Phantom Power Supplied by Bose Systems ==
-On the {{Classic}} / {{Model I}} the Power Stand supplies 24 volts for Phantom Power.<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|Phantom Power in Model I FAQ]]</ref>
+=== Phantom Power Available ===
-The {{T1}} provides 48 volts for Phantom Power.<ref>[[L1®_T1_ToneMatch®_Audio_Engine_/_FAQ#Do_the_mic_inputs_of_the_ToneMatch_audio_engine_have_phantom_power.3F|Phantom Power in T1® FAQ]]</ref>
+Phantom Power is available on
+* {{ToneMatch Mixers}} and {{T1}} 48 volts<ref>[[L1®_T1_ToneMatch®_Audio_Engine_/_FAQ#Do_the_mic_inputs_of_the_ToneMatch_audio_engine_have_phantom_power.3F|Phantom Power in T1® FAQ]]</ref><br>When you turn on the Phantom power, it is available on all XLR inputs. It cannot be turned on/off on individual channels.
+** {{T1}} channels 1, 2, 3
+** {{T4S}} channels 1, 2, 3, 4
+** {{T8S}} channels  1, 2, 3, 4, 5, 6, 7, 8
+*  {{Model I}}<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|Phantom Power in Model I FAQ]]</ref>
+** channels 1 and 2 turned on/off individually
+* {{Classic}}<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|Phantom Power in Model I FAQ]]</ref>
+** channels 1 and 2 turned on/off individually
-The {{ToneMatch Mixers}} provide 48 volts for Phantom Power.
+Phantom Power is available on
+* {{Classic}} / {{Model I}} the Power Stand supplies 24 volts for Phantom Power.<ref>[[L1®_Model_I_/_FAQ#I_thought_phantom_power_was_48_volts._Why_does_the_power_stand_only_supply_24_volts.3F|Phantom Power in Model I FAQ]]</ref>
-=== Will Phantom Power Damage Dynamic Microphones ===
-:Phantom power supplies have current limiting which will prevent damage to a dynamic microphone even if it is shorted or miswired. In general, balanced dynamic microphones can be connected to phantom powered mixer inputs with no problem.
-Source: [http://www.shure.com/americas/support/find-an-answer/what-is-phantom-power Shure.com]
+==== Current Limiting ====
+Bose Phantom power supplies have current limiting which will prevent damage to the Bose device if the connected device attempts to draw too much current.
+==== Turn Down Master Volume Before Turning on Phantom Power ====
+; Please turn down the Master Volume control before turning on phantom power
+This will avoid noise being sent out to the powered loudspeakers when you turn on the power.
+=== No Phantom Power ===
+There is no phantom available on
+* {{Compact}}
+* {{Model 1S}}
+* {{Model II}}
+* {{F1}}
+* {{S1}}
 == Phantom Power Connected to Bose Systems ==
@@ Line 37: / Line 64: @@
 You may want to connect your Bose Portable PA to an external system using the Line Out. All of the Line Outputs are line-level, balanced outputs. On the {{T1}}, T4S, T8S, {{Compact}}, the outputs are 1/4 inch (6.3mm). On the T8S, there are also XLR Outputs.
+=== Will Phantom Power Damage Bose Outputs? ===
 ;Will phantom power provided by the external system damage the Bose Portable PA system?
 The outputs of Bose Portable PA equipment have circuitry to protect them in case phantom power is turned on in the external system.
+=== 24V volt Phantom Power ===
+From Hilmar-at-Bose
+That is a somewhat difficult topic. We certainly have tried a KMS105 for live and even for recording with our 24V phantom supply and didn't find any problems. Then again, everybody's ears and taste is a little different, so I can't claim that there really isn't any difference.
+Going through the Alesis might also change things a little, so it's hard to do an exact apples-to-apples comparison.
+From a technical stand-point, it's difficult for me to believe that there are any issues. I haven't taken a KMS 105 apart yet (they ain't cheap !) but most Neuman mics use an internal DC to DC converter and polarize at 200V or so. If any, that should work better with a "proper" 24 V supply because it can provide nearly twice the overall power of a standard 48V supply. Getting more useable DC power was actually one of the reasons why the 24V standard was suggested.
+Different microphones do different things with Phantom Power but it's not only the voltage that matters but also the current. The original 48V/6.8kOhm standard was optimized for microphones that needed external polarization and therefore high voltage but nearly no current at all. But this type of microphone is exceedingly rare these days and the phantom power is used either to drive an internal pre-amp or to run an internal voltage-converter or stabilizer. For both cases a supply with lower voltage and higher current (and more overall power) is actually better and hence the 24V/1.2kOhm standard was derived.
+I hope I don't bore everybody to death with some math, but let's look at the example of the KMS105. I believe that at nominal 48 V the mic draws about 4mA. That current also goes through the internal 6.8k Ohm resistor of the phantom power supply and leads to voltage "sag". If we use Ohm's law we find that the internal effective resistance of the microphone is about 5 kOhms and that the voltage at the microphone terminals is only 20 V. All the rest is lost inside the supply. If you attach the same microphone to 24V/1.2kOhm supply the voltage sag is much less and the voltage at the microphone terminals comes out to be 19V. It's hard for me to believe that this 1 V difference should make any apprectiable difference in the mics performance.
+For an even more power hungry microphone that draws 5mA, the 24V/1.2kOhm supply will actually provide 3 Volts MORE (17V vs. 14V) at the microphone terminals. Sounds a little counterintuitive, but is actually true.
+Of course, in the end you have to be the judge of what sounds best to you ears.
+Hope that helps
+Hilmar
+Source: [https://www.bosepro.community/g/portable/topic/phantom-power-4?reply=18197182791945827#18197182791945827 Phantom Power discussion in the Bose Portable PA Community]
+==Questions==
+If you have questions about this article, please post a message in [https://www.bosepro.community/g/portable/topic/phantom-power-11 Phantom Power Discussion in the Bose Portable PA Community]
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