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Phantom power = destroyer of V-drum brains?

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  • #16
    Originally posted by MilosDrummer View Post
    Just to clarify. Don't confuse TRS output with line level unbalanced ones. A balanced output can be XLR or TRS, just a matter of connector, so if the output is balanced (should be stated in the spec sheet or the manual for the device), it needs no DI and suffers no trouble from the fantom power. Anything else like the direct outs from the TD30 is a line level unbalanced and needs a short(er) TS going to line in or a DI going to XLR in.
    This is what I started out thinking Milos, hence assuming it was ok to plug the balanced mimic outputs (the manual describes the trs outputs as balanced and given that the 25 pins of the DR25 convert to 8 channels it seems obvious to assume these are also balanced) straight into a mixing desk without worrying that a careless sound tech would kill a $2000 bit of kit by accidentally putting 48v down the line.

    However Mr Boo who I think knows the mimic inside out was pretty clear that it is not possible to connect the mimic outputs safely to anything that might inject phantom power.

    It would be great if someone could give confirmation as to whether or not it is safe to connect the mimic balanced trs and dr25 outputs direct to a mixing desk where there is a risk of phantom power being applied or not.

    Clarification will be massively appreciated!

    thanks

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    • #17
      As a follow up, presumably this https://m.thomann.de/gb/behringer_ultralink_ms8000.htm is the kind of thing people use between mimic and desk to protect against transmission of the 48v?

      I guess it will lead to a little signal impairment but I can live with that for the protection of my kit and I can find a way of bolting this to my rack.

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      • #18
        I have no experience with the Mimic, you'd have to check the specs. I was just stating that a true balanced output has no problem with phantom voltage since it is not grounded. If the manual or the specs sheet doesn't clearly state the kind of circuitry for any given device output, you shouldn't risk it.

        Mr.Boo My reference is general knowledge in electronics, but feel free to correct me in any specific case like the Mimic. There could be some new way to make a balanced output which evidently suffers damage from 48V?

        ​​​​Connecting any kind of line level device to a mic input is not good practise in my book, just go/switch to line or use a DI. Just because a device has balanced output doesn't mean it supposed to go to a mic input. The impedance is usually different, the sensitivity, the sound signature... and there's the phantom thing. Some mixers have XLR inputs that handle any kind of signal and you can switch between line and mic but those have +48 per channel. I'm sure that those with global phantom have separate inputs for line level (which can also be balanced)... Use them or use a DI
        Last edited by MilosDrummer; 02-26-19, 02:33 AM.
        °•A kits: Mapex Saturn ltd. Mapex Meridian, Ludwig and Pearl snares, Paiste, Anatolian, DW5002TW•°
        °•Roland TD-12 brain, SPD-SX, Roland RT triggers•°
        °•Ship kits: TD-12KV, TD-30K, TD-50K•°

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        • #19
          Good stuff, I know where I'm heading now. I have only driven digital desks til now that have no problem taking the line level outs (Roland and Behringer xr). I'll get one of these tx isolation boxes going forwards.

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          • #20
            Originally posted by MilosDrummer View Post
            Mr.Boo My reference is general knowledge in electronics, but feel free to correct me in any specific case like the Mimic. There could be some new way to make a balanced output which evidently suffers damage from 48V?
            Sorry, it's a strange answer.
            To my knowledge, the balanced line and phantom power isolation is two different things - unless you want to put decoupling transformers on line outs (and these would add much to the mimic cost and size)

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            • #21
              Hi!

              I would have added an external Phantom adapter (injector) for your headset only and kept the global Phantom power on the mixer off. Example: https://www.thomann.de/intl/behringer_ps_400.htm

              I am guessing your Mimic Pro cost like five-six times your (old?) Mackie Mixer. :-) On newer boards from Mackie you can pick and choose which channels that needs to supply 48V.

              Best Regards

              Anders / www.zourman.com



              Pearl CrystalBeat and Sonor Safari, Roland CY-14/13R/15R/12CR, RT-10x,2xBT-1,VH-11/12/13 & KD-10, Quartz, Pintech Dingbat, Triggera D14,D11, ATV AD-h14, 120MHz MegaDRUM with PS board, 2box 5&3, dd4SE, TD-9, Addictive Drums 2.1.8. All ADpaks, Microsoft Surface PRO, Macbook, Pearl Throne Thumper, Zourman HH & Ride Conv Kit www.zourman.com

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              • #22
                Lots of great help here, and much appreciated! I also emailed a local guy here named Mike Metz, who runs a business called Thesis Audio and is pretty much the go-to musical repair guru here in the Wichita area. Here's his reply:


                "Hi Mick,

                I looked up the technical manual for the TD30 and was surprised to see that the direct outputs are NOT isolated from phantom power, it may possibly damage the TD30.

                You will need to order an external phantom power box for the mic, as if the mixer had no phantom power. AKG and others make a small box that you plug the mic into and uses a standard wall power socket to run it with. I know that's a pain, but it would be safer on the TD30 that way.


                Glad you asked,

                Mike"


                It seems to me that it would be a lot easier to get a single mic preamp for the headset mic (thinking this: https://www.sweetwater.com/store/det...rophone-preamp) and turn off the global phantom power at the board than it would be to cover 7 channels (6 for the TD-30, 1 for my SPD-SX) of DI. Then again, I do play out live and someone's earlier warning about dodgy soundmen is still ringing in my ears (no pun intended)...
                TD-30 / SPD-SX

                Comment


                • #23
                  Originally posted by Mick Wade View Post
                  Then again, I do play out live and someone's earlier warning about dodgy soundmen is still ringing in my ears (no pun intended)...
                  I used to have a boss that would always preach - if it doesn't directly defy the laws of physics, users (we were in IT) would do it.

                  Hope you don't run into dodgy soundmen.

                  TD-25KV, Yamaha DXR15, MG10. Senn 280HD.

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                  • #24
                    Yup, I'm going to use a transformer isolation unit on my balanced outs now just in case someone leans on the button!

                    Comment


                    • #25
                      I totally do not understand this so please bear with me…....

                      I have my Mimic's headphone out and my laptop's headphone out both going to a Behringer 802 mixer. The Mimic's out is split R/L into the 802 Channels 3&4; the laptop into Channels 4&5. There is a "Phantom Power" button on the mixer. Are you saying if the phantom button is switched on, it could severely damage the Mimic? I do not use the phantom option but it most certainly could accidentally be activated.

                      Mixer.jpg

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                      • #26
                        Originally posted by Mick Wade View Post
                        Lots of great help here, and much appreciated! I also emailed a local guy here named Mike Metz, who runs a business called Thesis Audio and is pretty much the go-to musical repair guru here in the Wichita area. Here's his reply:


                        "Hi Mick,

                        I looked up the technical manual for the TD30 and was surprised to see that the direct outputs are NOT isolated from phantom power, it may possibly damage the TD30.

                        You will need to order an external phantom power box for the mic, as if the mixer had no phantom power. AKG and others make a small box that you plug the mic into and uses a standard wall power socket to run it with. I know that's a pain, but it would be safer on the TD30 that way.


                        Glad you asked,

                        Mike"


                        It seems to me that it would be a lot easier to get a single mic preamp for the headset mic (thinking this: https://www.sweetwater.com/store/det...rophone-preamp) and turn off the global phantom power at the board than it would be to cover 7 channels (6 for the TD-30, 1 for my SPD-SX) of DI. Then again, I do play out live and someone's earlier warning about dodgy soundmen is still ringing in my ears (no pun intended)...
                        Exactly why I said the same thing. It keeps it all separate, and you don't have to change anything else, or spend money on DI externals. A single mic-pre like we described will also usually be less cost than all the rest. Personally, I'd still look at the one I mentioned that also gives you extras like pre, comp, and general processing... something like this: https://dbxpro.com/en/products/286s
                        Alan
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                        • #27
                          Originally posted by EssKayKay View Post
                          I totally do not understand this so please bear with me…....

                          I have my Mimic's headphone out and my laptop's headphone out both going to a Behringer 802 mixer. The Mimic's out is split R/L into the 802 Channels 3&4; the laptop into Channels 4&5. There is a "Phantom Power" button on the mixer. Are you saying if the phantom button is switched on, it could severely damage the Mimic? I do not use the phantom option but it most certainly could accidentally be activated.

                          Mixer.jpg
                          No I think that you are totally safe. The photo shows the connections going into a line input which will not carry phantom power.

                          I don't know your specific mixer but the phantom will only be available on the xlr sockets (channel 1 and 2).

                          Comment


                          • #28
                            Originally posted by NathanE View Post
                            No I think that you are totally safe. The photo shows the connections going into a line input which will not carry phantom power.
                            I don't know your specific mixer but the phantom will only be available on the xlr sockets (channel 1 and 2).
                            Excellent - thank you Nathan. I have used the XLR sockets when a couple friends plugged their guitars into those inputs - everything seemed to work fine. Could phantom power potentially cause a problem with that?

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                            • #29
                              Yes, this is something that could cause a problem if the phantom is turned on.

                              It is possible to design the output stage of a device to incorporate either capacitors or a transformer to block the transmission of the dc, but as Mr Boo notes this adds cost, complexity and potentially size to a device. The way to protect against this is either use a transformer based passive di box between device and mixer, in which case keep your cable to the di from the device short to minimise noise, or if you are using multiple channels and have balanced signal outputs use something like the behringer ms8000 I linked to above to give multi chanel transformer isolation.

                              I had not realised until today that the output circuits in the mimic are not protected (in fairness like many devices, so this isn't a criticism). I will use tx isolation in future and given I send multiple channels to the desk I'll try the ms8000. The £60 it costs is lots less than a replacement mimic!

                              I have not used the ms8000 so can't rate it yet, but the behringer transformer dis are cheap and frankly very good. I have built a load of passive and active tube based dis in the past using Jensen txs which are lovely but pricey. The behringer ones are as good to my ear and a fraction of the price.

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                              • #30
                                In my opinion the only good protection is a transformer.
                                Good transformer takes space and has good cost =)
                                Mimic has 14 outputs...
                                behringer di800 (the cheapest 8 channel di) is about 200$, so you can easily add 400$ to retail mimic price (for the cheapest DI)
                                Taking in account that behringer is produced in much bigger volumes, and if we need at least slightly better transformers - it will be more like $600-$1000

                                for comparison - here is a reasonably good (not best) DI - https://www.bhphotovideo.com/c/produ...irect_Box.html
                                ~800$ for 8 channels
                                Last edited by Mr.Boo; 02-26-19, 06:39 PM.

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