Hello all

Has anyone come across any kind of hum on an XF?  I bought a used xf6 which works well even if I had to buy a new plastic end for it.  I have noticed though, after I plug into the 1/4 in jack on my new DXR10 powered speaker, that I get a lot of hum from the XF - after I get to about 1/3 volume on the speaker, and 80% on the motif, it’s really noticable.  I don’t get noise from anything else, and the speaker is quiet.

I have new cables, so that’s probably not it (balanced unbalanced issue maybe?), but just wondering if anyone had come across something similar.  Wondering if I need to take it to the shop.

Thanks

If you tore off that pesky little ground prong on the black power cord, most all your humming will go away. But others here may tell you about other solution that may or may not work.

It’s all in your ground wires, somewhere in your studio connections. To backtrack try connecting the XF to another wall socket first to ensure it’s not in the connection cable. Then start isolating each one, one by one.

jonnybignote - 13 May 2014 01:54 AM

[...]I have noticed though, after I plug into the 1/4 in jack on my new DXR10 powered speaker, that I get a lot of hum from the XF - after I get to about 1/3 volume on the speaker, and 80% on the motif, it’s really noticable.  I don’t get noise from anything else, and the speaker is quiet.[...]

Before going any further - please DO NOT defeat the third-pin power safety ground. There are ways to eliminate hum that don’t put you and your gear at risk.

It’s unlikely that your XF will require servicing. You’ve described a symptom of a ground loop. Here’s an example of a setup that uses a Yamaha mixer and DXR10 speakers without experiencing hum:
http://www.motifator.com/index.php/forum/viewthread/471172/

The XF’s outputs are unbalanced, and appropriate cables should have TS plugs.

A discussion about using Yamaha HS80M speakers, although the principles apply:
http://www.motifator.com/index.php/forum/viewthread/459446/

If you describe your setup in detail (all connections, type/length of cables, etc.), it might be easier to make specific suggestions.

Although I don’t own an XF, I had a similar experience with the XS8.  I ended up going with a quality stereo DI box (DI2 from Radial Engineering, though I’m sure there are alternatives that will work fine) and it solved ALL of the hum/noise issues across a variety of input components (analog and digital mixers, powered speakers).  Also a handy device to have around for both studio and live sound applications.

Oops - forgot to say, this has happened in live setting, not studio.  Both times, DI boxes were used, and I had experimented with the ground lift switches…

I will investigate more and peruse the links provided - thanks!

Are you using usb midi in the live setting?

The DXR10 is an 1100 Watt speaker - please use wisely. What I mean here is 1/3 up is very loud. Turning any amplifier up will generate noise and that’s a fact. It has to do with the signal you are sending in… useable signal before noise is what gain staging is all about. (Just saying, it may not be a ground issue at all).

Best example I can give is like a home stereo system (remember those) - you typically have several different things plugged into your Integrate Amplifier - a turntable (remember those?) a CD player (remember...), an FM Tuner, etc., etc.

If you turn the Power amp all the way up - the noise you hear is outrageous. But you would never do that because it is a matter of the signal you are sending in. Optimize the signal going in and set the amplified speaker output to what you need in the room. There is noise in any system - it is all about “useable signal” before NOISE.

I recently did a performance in a medium sized room comfortably sat around 200-250 people, I was using (2) DXR10’s I didn’t need to open the amp on the speaker past 9 o’clock, and I had to ask if I was too loud.

Your issue may not at all be ‘ground’ related so don’t assume that… (and never, ever, ever cut the the third prong off of a plug… only the foolish and soon fondly remembered folks do that!!!) Seriously that is to keep you from getting shocked to death. Why would you do that?

Cranking up a DXR10 should be reserved for rooms that seat over 1000 people.

When we introduced them we had a training session in a hotel ballroom and we opened them up… Yikes, the hotel manager couldn’t believe what was happening - the walls of the place were shaking!!! Clean but really LOUD.

Use with care. Optimize the signal you are sending in - if you are not sending in much, don’t use the amplifier in the powered speaker to boost your signal, boost it on the way into the powered speaker. Turn up your keyboard first.

Cables should be unbalanced - the XF is unbalanced. Using balanced cables does not/will not change this fact.

Professional high quality DI boxes as mentioned by tcamp are always an asset to have for different gigging situations.

Or a small quality mixer can solve many issues for you (I just got the little Yamaha MG06X - small enough to throw in my utility bag - killer pre-amps, balanced outputs, metal construction, mounts on a mic stand w/optional kit, a great problem solver - and not expensive)!!! XLR outs for the house system, Balanced 1/4” outputs from my stage monitors, ah! heaven!!! Like someone was reading a keyboard player’s Christmas list!

Also you mentioned 1 DXR10 speaker, I’d be remiss if I didn’t encourage you to get the other one - they work better in pairs.
:-)

Let us know.

Nobody has to follow my lead, but after I tore off the that third prong, all my humming problems went away forever. If tearing off the ground prong wouldn’t have worked, I would have had to toss the Motif in the garbage as distracting second hand quality electronic workmanship. Yamaha keyboards are the only electronic equipment out of the hundreds of pieces of equipment and brands I’ve ever bought to ever make distracting humming noise.

And mine was a simple solution to eliminate the hum from the machine first, starting at the plug before I payed another dime to fix the machine defect.

kday - 15 May 2014 02:18 AM

Nobody has to follow my lead, but after I tore off the that third prong, all my humming problems went away forever. If tearing off the ground prong wouldn’t have worked, I would have had to toss the Motif in the garbage as distracting second hand quality electronic workmanship. Yamaha keyboards are the only electronic equipment out of the hundreds of pieces of equipment and brands I’ve ever bought to ever make distracting humming noise.

And mine was a simple solution to eliminate the hum from the machine first, starting at the plug before I payed another dime to fix the machine defect.

Nobody should follow your lead. A failure in the Motif or in another piece of gear attached to it could result in a life-threatening and/or equipment-threatening situation. There have been detailed threads on this topic, but apparently most were about the XS and lost along with that forum.

I’m not going to discuss Yamaha’s design choices. The point is, if there’s hum due to a ground loop, it can be dealt with in a safe manner.

Some hopefully helpful information:
http://www.jensen-transformers.com/an/generic%20seminar.pdf
http://www.rane.com/note110.html
http://peavey.com/support/technotes/safety/shockhazard.cfm

Excellent advice and references, 5pin!

Bad_Mister - 14 May 2014 04:46 PM

The DXR10 is an 1100 Watt speaker - please use wisely. What I mean here is 1/3 up is very loud. Turning any amplifier up will generate noise and that’s a fact. It has to do with the signal you are sending in… useable signal before noise is what gain staging is all about. (Just saying, it may not be a ground issue at all)....

If you turn the Power amp all the way up - the noise you hear is outrageous. But you would never do that because it is a matter of the signal you are sending in. Optimize the signal going in and set the amplified speaker output to what you need in the room. There is noise in any system - it is all about “useable signal” before NOISE....

I recently did a performance in a medium sized room comfortably sat around 200-250 people, I was using (2) DXR10’s I didn’t need to open the amp on the speaker past 9 o’clock, and I had to ask if I was too loud....

This is a very good point from Bad_Mister.  Send as good a signal as you can before you turn up the DXR10.  You won’t need to turn up the DXR nearly as much as you may be used to!

I quite often have my DXR10’s set at even less than 9 o’clock...7:30 or 8:00.

I can make a lot of noise with my DXR’s too...send a weak signal and then crank up the volume on the speaker’s amp.

Anyway, just be sure you check the gain staging before spending a lot of time and money on grounding issues.

BTW, I run my keyboards at full volume at the signal-out.  Maybe boost your 80% to full and give that a try.

The hum/buzz you get 99% of the time is due to the PA ground (via the DI) not being the same as the stage wiring ground. The noise is actually AC passing between the grounds...being 50 or 60 hZ you hear a low hum (and often the harmonic at 100/120 hz). If you unplug the XLR from the DI and the buzz stops you have the culprit.

While I’m 100% with 5-pin about the safety implications of removing the ground lugs from power cords, I will mention that you don’t have to rip off the pin!

Go to a hardware store and for $1 or less get a 3 prong to 2 prong adapter. I keep one in my gig bag at all times in case I have to play somewhere that only has 2 prong outlets (current US building code requires 3 prong in new construction but plenty of older buildings still have 2 conductor wiring). These can be used in a emergency to do ground lifting on gigs when nothing else will kill the hum.

HOWEVER

While you are buying your adapters at the hardware store, buy a simple AC voltage tester. Most look like half a ballpoint pen with two wires coming out one end and small lamp on the other end. You use these to check for ground faults.

Ever see guitar players brushing their strings against stage mikes looking for sparks? The tester is used for the same thing, touch one lead to a mike (grounded to the PA) and the other end to the ground (sleeve) of the 1/4” cable plugged into your XF. If the light comes on then you have 120V flowing between those two grounds and you are risking electrocution. Usually flipping the 2 prong plug over in the outlet clears the grounding issue.

ALSO

Consider buying an isolation transformer. I have one made by A.R.T. that has XLR, 1/4 and RCA jacks on one unit. Each side is ground isolated from the other.  It also works as a handy converter between different cable types.

meatballfulton - 17 May 2014 09:07 AM

[...]While I’m 100% with 5-pin about the safety implications of removing the ground lugs from power cords, I will mention that you don’t have to rip off the pin!

Go to a hardware store and for $1 or less get a 3 prong to 2 prong adapter. I keep one in my gig bag at all times in case I have to play somewhere that only has 2 prong outlets (current US building code requires 3 prong in new construction but plenty of older buildings still have 2 conductor wiring). These can be used in a emergency to do ground lifting on gigs when nothing else will kill the hum.[...]

Using a 2-wire to 3-wire adapter to “lift” the power safety ground is just as risky as removing the ground pin from a power cord. The only “advantage” to using an adapter in that manner is that an innocent power cord doesn’t suffer mayhem. The adapters are designed as a means of providing a third-wire ground when there isn’t a proper outlet, not for defeating a ground that already exists.

Hopefully the venues being played in are providing power that’s GFCI (Ground Fault Circuit Interrupter) protected. A properly working GFCI should limit current to non-lethal levels, even if the third-wire safety ground has been defeated.

I suspect that the reason removal of the safety ground is still acceptable practice by some is that the incidence of electrocution isn’t high. Nevertheless, it does happen - and damage to gear is probably more prevalent. I’ve seen input and output stages that have evidently been fried by stray AC currents - if you don’t highly value your life (and possibly that of others), at least respect your gear.

I just hope there aren’t too many Motifator members who gamble this way.

By the way, defeating the safety ground is against both IEC and OSHA regulations. If nothing else, any venue that allows equipment to be used when the safety ground is intentionally disconnected could be fined and/or be liable for injuries, etc.

Click thumbnail to see full-size image

Thanks everyone for the help and advice, and sorry it’s taken me a while to get back to this thread.

Bad_Mister, I will probably get another DXR10 in time, though for now, I’m only using as a monitor and two of them would be overkill for that.  Just to confirm, I am sending 80% or more from the Motif and therefore only needing around 10-11 O’Clock on the DXR10 - I think I’m easily sending enough from the Motif. 

I’ve now replicated the same problem on a concert hall and in a jazz club.  Both times going through DI boxes.  Any other signals going to the DXR10 seem to be fine.  Could I be using the wrong kind of cable (I just use essentially guitar cables) or in both cases, are the DI boxes I’ve plugged into not good enough?  I would buy my own to get rid the problem, but not until I knew it would work.  The isolation transformer might be the way forward also, though again, wish I knew ahead of time.

5pinDIN - I won’t be defeating the ground on the Motif - besides the inherent safety risks, I don’t see why I should need to do that on an instrument such as this.

I’m usually surrounded by guitarists and bassists with all that they usually have going on - banks of pedals, overdriven amps and the like, and I can’t believe I’m the one with the dirtiest sounding rig…

Bad_Mister - I like the idea of the mixer also and might look into it, though I’m loath to add yet another piece of kit to my utility bag…

Thanks again everyone

jonnybignote - 30 May 2014 03:25 PM

5pinDIN - I won’t be defeating the ground on the Motif - besides the inherent safety risks, I don’t see why I should need to do that on an instrument such as this.

I’m glad that’s your attitude.

Getting back to trying to resolve the problem… several posts ago I asked for some information (but got no reply): “If you describe your setup in detail (all connections, type/length of cables, etc.), it might be easier to make specific suggestions.” The more data you provide, the better the chances of determining what’s happening and coming up with a solution.

jonnybignote - 30 May 2014 03:25 PM

I’m usually surrounded by guitarists and bassists with all that they usually have going on - banks of pedals, overdriven amps and the like, and I can’t believe I’m the one with the dirtiest sounding rig…

While bassists often DI, guitarist almost never do...they are miked. So there is no possibility for ground loops with the PA.