NS2 Power Supply Creating Lots of Static

[classicrockguy]

I keep thinking there is no place else to go with this, but let me try and clear the air one more time on the nature of the problem.

1) It affects lots of other unrelated gear including both our lead guitar player and our bass players rig (their pickups, specifically). It is NOT just my guitar rig.
2) It shows up at our drummer's house during rehearsals, and at the few gigs we've played so far this year in different venues. It is NOT something environmental in my home practice room.
3) It occurs regardless of the AC power source. Everything is plugged in to a Furman P-1800 PF power conditioner (yes, I have tried it without that device, as well). I have also tested on a high-end Honda generator. This is NOT an AC power source problem.
4) It occurs regardless of whether the NS2 is connected to anything else beside AC power. It is NOT an audio problem coming through the NS2 audio feeds to the board.
5) It ceases IMMEDIATELY when the NS2 is powered off, and starts IMMEDIATELY when the NS2 is powered on.
6) It is NOT an acoustic noise problem. Under very quiet circumstances, my NS2 power supply produces an audible acoustic hum (not an audio hum). This is a tiny bit annoying, but not at all a problem for live use. (Could bother some in a studio recording situation.)

I appreciate everyone's comments. However, I see no further debate on what is going on. MY NS2, as well as the other new one Sweetwater sent me, emits strong (EMF?) interference (from the power supply?) that is picked up by other devices nearby, especially guitar and bass coils. Granted I could have gotten 2 "bad" ones in a series, but I don't have any way to test any further. (Nor do I have the energy.) Maybe I really do have a defective power supply in my unit. If the Nord folks want to send me another power supply (perhaps one that has been thoroughly tested), I am more than willing to change it out in an attempt to resolve the issue. If they want to talk about any other possible solutions, I'm glad to engage. However, it is not helpful for folks to keep implying there is something wrong with my guitar rig or my power or my environment. It is simply not the case.

[RedLeo]

it is not helpful for folks to keep implying there is something wrong with my guitar rig or my power or my environment.

With respect, nobody, outside any official dealings you may have had with Nord, has said or implied any such thing. At your repeated request:

I would love to know if anyone else on this forum has put a typical electric guitar and rig with a typical overdriven signal chain near an NS2 and had any of this same issue

other forum members have related their experiences with their guitar rigs. One other forum member has reported a problem similar to yours on an earlier model Stage, and has stated that, like you, he believes the problem to be the power supply in his instrument. The rest of the members stated that they have had no problems. That is all.

However, I see no further debate on what is going on.

We're musicians, not rocket scientists. What more can we really do?

[pterm]

@classicrockguy,
From your listed items #3 and #5 I conclude your Nord clearly exhibits radiated electromagnetic interference.

I don't suggest you try this yourself, and it's unlikely Nord's US distributor is equipped to do this. It's unlikely that even Nord HQ has the equipment or expertise to do this...

The problem with diagnosing this further is the specialized equipment and effort needed: It requires near-field RF (radio frequency) probes and either one or both of a spectrum analyzer (preferred) and/or an oscilloscope to determine whether this is either:
a.) radiated power-line interference at 60Hz or
b.) higher-frequency carrier being modulated at 60Hz.
Finding the prescence of one or both of these determines the next step in the diagnoses.

If the test equipment detects only 60Hz, it indicates a problem at the power supply. Opening the instrument and probing the input cables, output cables and transformer would indicate what element of the power supply might out-of-specification, but ultimately replacing the power supply provides the simplest means to attempt to remedy the problem.
If the test equipment detects a higher-frequency carrier being modulated at 60Hz indicates either out-of-specification power supply output filtering or out-of-specification components on the processor board. Identifiying whether the problem exists on the processor board or power supply requires further probing and analysis. Having a replacement power supply for comparison would be helpful.

From a practical standpoint, I think replacing the power supply provides your best next step. Since the instrument is under warranty, I hope the US distributor helps with that.

You mentioned many different devices that malfunction when the Nord is powered... if you find it interferes with telephones, televisions or licenced radio (WiFi, wireless microphones, or cordless home phones are all unlicensed) some other options exist. Let us know if you notice this.

[RedLeo]

Well, ok - one rocket scientist....

[neolithic]

Well, ok - one rocket scientist....

good one Leo! I think pterm will take that as a compliment! Ha ha !

[Mr_-G-]

Thanks Pterm. No rockets where I work but I am in a 50Hz location, and tested this EMI with a simple coil:
http://www.norduserforum.com/nord-stage ... tml#p50033
and later with a guitar. The noise exists when very close to the instrument and it is loudest near the synth Oscillator red LED display, so I am pretty sure it is coming from the transformer:
Have a look:

RF.jpg (74.95 KiB) Viewed 2825 times

The peaks happen at 50Hz and integer multiples.
I found a similar issue with a Roland JX8P, so this is not unique, but since I do not play the guitar it has never been an issue for me. I understand the frustration of classicrockguy, though.
Note that single coil pickups are the transducer to capture this kind of EMI and the fact that some pickup combinations get less noise (maybe they are humbuckers?) seems to make sense too (after all the humbuckers were designed exactly for that reason). In this sense it is difficult to decide who's "fault" it is. Sure Clavia might see if it is possible to design better less leaky transformers, but if we are to use coils+preamps+amps around equipment that close, unavoiding this kind of situation is perhaps difficult.
Not knowing a lot about FCC or AVIS regulations, I guess that guitars might be a 'grey area' or perhaps not covered at all, as they are not "digital apparatuses" and at the same time the NS2 passes those standards according to the manual.
So what to do next?
* I suggested some time ago to try and insulate the transformer better (so more like a Faraday cage) with some metal thin sheet or similar although I do not know if this is a dangerous thing in terms heat dissipation, etc. Note that the metal shielding cover where the transformer sits has many 'holes' and it is not insulated underneath.
* A non-ideal, alternative might be to investigate a different type of pickup for the guitar, like a piezo electric one?
* Moving the transformer outside the chassis might be possible, but I would not be looking forward to do add some multi core cable from the transformer to the instrument...

[pterm]

Thanks Pterm. No rockets where I work but I am in a 50Hz location, and tested this EMI with a simple coil:
http://www.norduserforum.com/nord-stage ... tml#p50033
and later with a guitar. The noise exists when very close to the instrument and it is loudest near the synth Oscillator red LED display, so I am pretty sure it is coming from the transformer:

The peaks happen at 50Hz and integer multiples.

@Mr.G,
Solid analysis: I performed the same one with your MP3 (in audacity too it looks like) when you submitted it.
Your MP3 sample clearly shows your problem originates at the power supply. The MP3 sampling limits its frequency range to the acoustic band, so it's impossible to tell if this audio-band signal is demodulated from a higher frequency carrier or if it is only at power line frequency (50/60Hz depending on location). Hence the need for a higher-bandwidth instrument like an oscilloscope or spectrum analyzer.

Note that single coil pickups are the transducer to capture this kind of EMI and the fact that some pickup combinations get less noise (maybe they are humbuckers?) seems to make sense too (after all the humbuckers were designed exactly for that reason). In this sense it is difficult to decide who's "fault" it is. Sure Clavia might see if it is possible to design better less leaky transformers, but if we are to use coils+preamps+amps around equipment that close, unavoiding this kind of situation is perhaps difficult.

I agree. I assume, given classicrockguy's experience, he either tried these methods already or can't make the compromise to a less-susceptible pickup to get the sound he needs.

Not knowing a lot about FCC or AVIS regulations, I guess that guitars might be a 'grey area' or perhaps not covered at all, as they are not "digital apparatuses" and at the same time the NS2 passes those standards according to the manual.

The regulations bottom out at 150kHz (for CISPR in the EU) or 450kHz(for FCC in USA) for conducted emissions and in the MHz for radiated emissions. This is another reason to use higher-bandwidth test equipment. If the interference falls into a regulated band, Nord's obligation to remedy the problem increases. --I think this is a moot point though: Nord charges premium prices for this equipment. Operating a Nord in proximity to normal guitar pickups without power interference is an obvious use case, so I believe the original design met this. From pablomastodon's perspective, classsicrockguy's experience is abnormal. It seems obvious, to try replacing the power supply under the assumption that the batch (from which the two Sweetwater Nords came from) was faulty.

So what to do next?
* I suggested some time ago to try and insulate the transformer better (so more like a Faraday cage) with some metal thin sheet or similar although I do not know if this is a dangerous thing in terms heat dissipation, etc. Note that the metal shielding cover where the transformer sits has many 'holes' and it is not insulated underneath.
* A non-ideal, alternative might be to investigate a different type of pickup for the guitar, like a piezo electric one?
* Moving the transformer outside the chassis might be possible, but I would not be looking forward to do add some multi core cable from the transformer to the instrument...

Reasonable ideas, but I suggest exhausting options that keep classicrockguy's instrument in warranty if possible.

[classicrockguy]

For the record, my PRS McCarty guitar has humbuckers. Further, all of the cavities are carefully copper foil lined. Interference occurs in varying degrees based on proximity to the NS2, humbuckers vs single coil (I can pull the tone knob to get a single coil tap), and gain structure. Humbuckers more than about 1-2 feet away on a low gain signal chain are almost quiet. Single coil within 12 inches of the NS2 on a high gain signal chain is completely unusable. The interference is as loud as a strum. Changing these parameters yields everything in between.

[Keysplayer]

I sure hope one of you may have a solution. I have a Nord Stage Classic 88 which I use with a Sennheiser in-ear monitor system and I'm getting a tremendous amount of noise ONLY when I use the IEM with my Nord connected to the mixer, and only when I'm using the wireless transmitter from the IEM in conjunction with the wireless receiver. They work perfectly together when I connect headphones directly to the transmitter and bypass the receiver, so I know the direct connection works fine. When I connect my bass, my guitar, vocals, another keyboard I own (a Roland Fantom), and anything else through the mixer and through the wireless system it's fine also. I use the IEM receiver with another transmitter when we play out and its fine.

I still get signal, I can hear the Nord, but there's a tremendous amount of noise in the connection, it's not clean at all. I've changed and exchanged cables from the XLR connection of the transmitter to the mixer, I've changed 1/4" patches from the keyboard to the mixer, no change. It's only the Nord, and it's only the wireless connection. Incidentally there's no issue hooking up headphones directly to the Nord, there's no problem monitoring the Nord through the mixer or PA...it's literally only having this issue in the situation I'm currently describing. The moment I disconnect the Nord it stops.

Have any of you ever had experience solving this issue with Nords putting out some sort of RF interference which could be a problem?? I've tried all sorts of different frequencies and no change...I'm left with believing the Nord is somehow putting out a broad spectrum competing RF signal which is interfering through the whole range of frequencies. Have no idea what to do next - and could use some help!!

Thank you very much in advance!
Matt

[Merlimau]

Hi Keysplayer

I’m not an electrical specialist. For me it sounds like an antenna effect with the XLR connection from the keyboard to the mixer, maybe in conjunction with the missing electrical grounding of the Nord keyboard.

Just for test: If you connect the headphone output to the mixer it happens as well? If the noise is gone than it could be the 2 XLR lines from Keyboard to the mixer. Then you can try the following to use the XLR connection: shorten the cable length by a third or 2 third (do not shorten the cable by half or a quarter). And try again. Don’t lay the cable exactly parallel and don’t tie it together. Let the cable as loose as possible. Do you use shielded XLR cable?

Cheers Merlimau