Keyboards with XLR outputs

[time4jazz]

I have a CP73, which, like some other keyboards, has XLR outputs.  Although this can be very convenient, I wonder if the keyboard’s output circuit is protected against phantom power that’s accidentally switched on at the mixer. If instead, audio is run from the keyboard’s 1/4” jacks and then through a DI box, the DI’s transformer protects against the accidental DC voltage. Does anyone know if the output circuit is protected when using the keyboard’s XLR outputs?  Thx

[mynameisdanno]

Unless specifically advertised as having output transformers, I tend to assume they do not.  After learning that lesson the hard way a couple times, I wish manufacturers would stop providing stage gear with XLR outputs unless they're properly isolated.  It's just asking for trouble.  It's not even a question of accident or negligence on the part of the audio engineer sending 48V where it's not needed; some lower-end mixers only have a global phantom power switch.

[jazzpiano88]

I would insert my own transformer to be safe.  Radial JDI Duplex for example.  Bonus is you get the nice Jensen sound.

 

Edit:  I became aware of this issue back in the 80's.  Gallien Kruger produced a keyboard amp with XLR outs for connection to an outboard PA.

One gig I connected it to the band's PA and the speaker displaced itself by about 2 inches and was basically destroyed.    Even after speaker replacement, the amp was never the same, so I suspect some additional damage was done.

[time4jazz]

Thanks for the replies.  I’m glad I asked!  I will definitely go through a DI box.  It’s amazing they include XLR outs on the keyboard — it’s just asking for trouble. 

[Reezekeys]

I don't quite get having XLRs on stage keyboards, or any keyboard you're doing a gig with. Either a) you're using your own amplification that's near you, so unbalanced cables work fine, or b) you're playing at a bigger venue where you're going into a house sound system, in which case there's likely DI boxes provided.

 

I blew out a Mackie SRM450 using the pass-through XLR to go to the house sound system, which had phantom power on. Since then I occasionally continued to connect like this but only after making sure phantom power was off on the board. Then at one gig I had a sound person I just met tell me phantom was off, but I happened to look at the board and saw he was either stupid or deliberately lying. Since then it's an automatic NEVER to plug into a board like this, as convenient as it might be. Never trust a strange soundperson – especially if it's just a tech doing stage setup and not the actual FOH engineer. You think joe schmoe cable plugger-inner is gonna reimburse you for the repair on your CP?

[jazzpiano88]

34 minutes ago, time4jazz said:

Thanks for the replies.  I’m glad I asked!  I will definitely go through a DI box.  It’s amazing they include XLR outs on the keyboard — it’s just asking for trouble. 

 

XLR outputs are fine if you control the signal chain and are connecting it up in your studio situation.

 

It would be really interesting to find out if Yamaha's keyboards can handle phantom power. I am guessing that it can, just because of the number of pro players using these boards (all Yamaha CPs have the XLRs)   Maybe a call out to Bad Mister on the Yamaha Forums.

[Mighty Motif Max]

The Roland Fantom models come to mind as well - I’ve done gigs both ways but it would be nice to know.

[CowboyNQ]

I never use the XLR outputs on my SV-1 for this exact reason.  Always go unbalanced through a DI before heading to FOH.

[D. Gauss]

Use the XLR outs to go to your keys amp (assuming it's a powered QSC speaker or whatnot) as the signal is hotter (+4) and use the 1/4" (-10) via DI to FOH.

 

[ITGITC]

10 hours ago, Reezekeys said:

Never trust a strange soundperson 

 

Wait. 

 

I've honestly never met a soundperson who wasn't.    

 

ITGITC? 

 

[Stokely]

Agreed that XLRs are not useful for my needs.  I use a Key Largo mixer with 1/4" ins and which has DIs built in.  If I didn't use this, I'd have my own DIs or use those provided.  I always have the KL even with only one keyboard, it's on my pedalboard and it's part of the chain.  All XLRs do is make it so that I need an adapter cable.

[Al Quinn]

I learned the hard way that the CP4’s XLR outs are not transformer isolated. Fortunately, Yamaha paid for the repair. But, don’t let this happen to you!

[MAJUSCULE]

You learn something new everyday... and sometimes it's important stuff like this!

[EscapeRocks]

For those times I'm running XLR out of my rack to FOH, I have a pair of the Radial Ice Cube boxes.   They prevent 48v coming to my gear, and also clean up any possible bad stuff.

 

[PianoMan51]

My jaw is hanging down! In a former life I designed hardware for a telecom test company. The incompetence of designing an XLR output, meant to connect with a mixer, and NOT protecting against 48V phantom power from the mixer is…

 

I don’t have words that I would choose to use among friends.

[TommyRude]

2 hours ago, Stokely said:

Agreed that XLRs are not useful for my needs.  I use a Key Largo mixer with 1/4" ins and which has DIs built in.  If I didn't use this, I'd have my own DIs or use those provided.  I always have the KL even with only one keyboard, it's on my pedalboard and it's part of the chain.  All XLRs do is make it so that I need an adapter cable.

maybe I'm missing something - the Key Largo's main outs are XLRs?

[SamuelBLupowitz]

Yikes, I've been using the XLR outs on my CP88 all this time. It never occurred to me that this could be a problem.

 

If anyone finds out more from the Yamaha forum, let me know, but otherwise, I think I'll be making some changes in my habits (like asking for a DI regardless).

[Reezekeys]

This is interesting, a box that does dual duty as a DI for 1/4" unbalanced sources and as an isolator for XLR sources. Stereo too. Not exactly cheap but for what it does could be worth the expense - 

 

https://www.whirlwindusa.com/products/black-boxes-effects-and-dis-transformers-isolation-devices-iso-2-dual-line-level-isolator-and-balancer

 

 

[EricBarker]

1 hour ago, PianoMan51 said:

My jaw is hanging down! In a former life I designed hardware for a telecom test company. The incompetence of designing an XLR output, meant to connect with a mixer, and NOT protecting against 48V phantom power from the mixer is…

 

I don’t have words that I would choose to use among friends.

Me too, reading this thread leaves me extremely perplexed. Are people saying that these boards aren’t protected at all from simple 48V phantom, or that they’re not protected from accidental surges that are far greater than that? Because if we’re saying that turning on 48V will kill a keyboard… that’s absolute lunacy!!!

[Adam Burgess]

I kind of wish everything was on PowerCon for mains, and XLR for audio.

I know Sennheiser mic receivers are fine with +48V - I would expect Shure AND the big keys manufacturers to be the same. But, it seems not.

I had a Roland XP50 back in the day, which got its ground thru the audio connection (only a 2 pin mains in), and a dodgy venue's power killed the power supply.
Electrical stuff just needs to be safe, on a component level, as well as for us beings on stage. 

[Stokely]

1 hour ago, TommyRude said:

maybe I'm missing something - the Key Largo's main outs are XLRs?

They are, I mean that the inputs are 1/4" so if my keyboard had XLRs it would require me to have an adapter or cable instead of regular instrument cables.

I hadn't really wondered about connecting to a mixer and dealing with phantom power.   The only mixer the KL connects to are main PA mixers where you'd have options to turn that off per channel.  That said, not sure what would happen if that were on for my channels.

[Reezekeys]

2 hours ago, EricBarker said:

because if we’re saying that turning on 48V will kill a keyboard… that’s absolute lunacy!!!

 

Really? If the output stage of a keyboard's analog outputs aren't capacitor-coupled, seems to me 48 DC volts would be a pretty unhealthy thing for them to experience. Even with a cap blocking DC, it may be only be rated to a typical voltage for the design, which might be far less than 48V. I will of course defer to the more knowledgeable folk on this forum but as I said, when it comes to PPAs with XLR pass-thrus I can attest to one Mackie down from phantom power. Also, a QSC forum post I saw, from a QSC engineer warning not to use the pass-thru on a K speaker to go to a sound board for the exact reasons we're discussing here.

 

What's lunacy imo is not mentioning this potential circuit-zapping issue in any of the manuals for these pieces of gear!

[MAJUSCULE]

11 minutes ago, Reezekeys said:

What's lunacy imo is not mentioning this potential circuit-zapping issue in any of the manuals for these pieces of gear!

 

Agreed. I checked the CP88/73 manual last night to see if there was an answer and there is no mention of it anywhere.

[Al Coda]

2 hours ago, Reezekeys said:

This is interesting, a box that does dual duty as a DI for 1/4" unbalanced sources and as an isolator for XLR sources. Stereo too. Not exactly cheap but for what it does could be worth the expense - 

 

https://www.whirlwindusa.com/products/black-boxes-effects-and-dis-transformers-isolation-devices-iso-2-dual-line-level-isolator-and-balancer

 

 

 

Yeah,- good find.

Line isolation box makes sense on live performance situations,- and it´s good it works as a line level DI box as well.

 

There´s a nice price multichannel one,- ART T8 ... about 30 bucks per channel and offering cinch connectors in addition to XLR and TRS.

 

I recognize the Radial Keylargo mentioned above comes w/ isolated outputs already as does my Ashly MX508 mixer.

 

 

A.C.

[cphollis]

FWIW I prefer 1/4" outs on my instruments, that way they plug into almost anything -- except a mixer that wants a DI and might try to send 48V .   As long as we're talking about DIs and whatnot, I picked up a dandy 4-channel Behringer powered DI (+6db/12/18) for my rack, and it's nice now always having plenty of gain.

 

 

[EricBarker]

1 hour ago, Reezekeys said:

 

Really? If the output stage of a keyboard's analog outputs aren't capacitor-coupled, seems to me 48 DC volts would be a pretty unhealthy thing for them to experience. Even with a cap blocking DC, it may be only be rated to a typical voltage for the design, which might be far less than 48V. I will of course defer to the more knowledgeable folk on this forum but as I said, when it comes to PPAs with XLR pass-thrus I can attest to one Mackie down from phantom power. Also, a QSC forum post I saw, from a QSC engineer warning not to use the pass-thru on a K speaker to go to a sound board for the exact reasons we're discussing here.

 

What's lunacy imo is not mentioning this potential circuit-zapping issue in any of the manuals for these pieces of gear!

 

What I meant, was it's lunacy that it's not built with that protection in mind, not that the posters here are wrong. Seems like a fairly simple thing to consider and fix with cap blocking to 48V. I mean, it's going to be almost impossible to make absolutely sure the mixer never has phantom turned on. And as it's been mentioned, many cheap house systems have a global +48V switch. I would think building in voltage protection would be top priority. XLR outs already implies that it's likely a higher-grade keyboard, you don't find those on Casiotones. At $1000+, the least they can do is put $10 toward some road-grade voltage protection.

But I generally agree, XLR outs from a board are pretty unnecessary. At line-level, no one needs balancing for less than 15ft, so run 1/4in to an amp, and 1/4in to DIs or a KeyLargo. If they built-in some road-worthy DIs into the board, that would be a nice perk, but unprotected XLRs are really really silly.

[Delaware Dave]

I used 1/4" TRS outs either out of my keys or my mixer's outputs to FOH.  This gives me the +4db as well as eliminating any potential phantom power horrors.  The only time I use the XLR outputs from my own mixer is if I'm going into my own EV speaker.  FOH connection from my own mixer is either 1/4" TRS or 1/4" TS to a DI box to the FOH.  We do alot of outdoor concerts using unknown soundmen supplied by the venues; they supply everything, including mics.  I'm not paying attention and I don't know if those mics that they provide us use phantom power, so in those situations I always use a DI (mixer 1/4" TS out to DI) to avoid any potential issues and I bring my own DI's as well as I don't trust something that is handed to me, not knowing if there actually is an isolation transformer in 'their' DI box.  Knock on wood, never had issues doing it my own way ......

[Reezekeys]

5 minutes ago, EricBarker said:

What I meant, was it's lunacy that it's not built with that protection in mind, not that the posters here are wrong.

 

Sorry for misunderstanding. I didn't think you were calling anyone wrong though – I misread your sentence as meaning any keyboard should be able to handle 48V at its output! Of course if these keyboards had real transformers connecting their XLR outputs it wouldn't be a concern. Something tells me that's not the case, but as with many of my wild guesses, I could be wrong! My reasoning is that decent audio-grade transformers cost money, but putting cheap ones in could mean the 1/4" outputs sound better than the XLRs.

[Al Quinn]

2 hours ago, EricBarker said:

Me too, reading this thread leaves me extremely perplexed. Are people saying that these boards aren’t protected at all from simple 48V phantom, or that they’re not protected from accidental surges that are far greater than that? Because if we’re saying that turning on 48V will kill a keyboard… that’s absolute lunacy!!!

The issue I had when I connected the CP4 XLR outs to a pro sound company’s FOH wasn’t that it killed my keyboard. Rather, something got damaged and the sound was less than pristine. It was a celebrity big band gig and the piano was rarely exposed enough to hear the subtle damage. It didn’t impact the gig but the CP4 took a hit of some sort. I didn’t even notice until I heard it at home. It was literally the first and only time I used the XLR outs and I only did it because they were short a direct box and I loaned them my Radial Pro D2.

[Al Quinn]

1 hour ago, Reezekeys said:

 

Really? If the output stage of a keyboard's analog outputs aren't capacitor-coupled, seems to me 48 DC volts would be a pretty unhealthy thing for them to experience. Even with a cap blocking DC, it may be only be rated to a typical voltage for the design, which might be far less than 48V. I will of course defer to the more knowledgeable folk on this forum but as I said, when it comes to PPAs with XLR pass-thrus I can attest to one Mackie down from phantom power. Also, a QSC forum post I saw, from a QSC engineer warning not to use the pass-thru on a K speaker to go to a sound board for the exact reasons we're discussing here.

 

What's lunacy imo is not mentioning this potential circuit-zapping issue in any of the manuals for these pieces of gear!

For me, what’s even worse, is to market the XLR outs as being a great feature for connecting directly to a PA. It’s almost criminal to promote something that can potentially damage the keyboard.