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[dave ingland]

Hi, I have a Yamaha digital stage piano that all of a sudden started having a buzzing, crackling sound coming from it. It has worked fine for years with no problem until now. The buzzing noise can be heard whether it is connected to a portable Roland KC500 keyboard combo amp at home or the church sound system through a DI with ground lift or not. Also, even with the keyboard volume off, the sound can still be heard. It's not a constant low-level hum. Instead, it's a very noisy medium-pitch buzzing sound accompanied with crackling.

It has an external power supply (wall wart) that does not have a 3-prong plug with ground. From what I've read about ground loops, I don't this is the issue since it's not a low-level hum, but wondering if maybe the power supply is the culprit as it's from Radio Shack and not the original Yamaha power supply. However, it has been fine even with the RS power supply for several years.

I have already gone through the usual checks such as: changing instrument cables, using different wall outlets, trying different DI boxes (remember, same issue from 1/4" into combo amp as 1/4" to xlr via DI), decreasing keyboard volume, increasing PA volume, increasing keyboard volume, decreasing PA volume, etc. Any ideas on what else to check? Thanks!

[Gene Simonalle]

Do you get the same sound problem with the headphone jack?  If you do, I suspect there is a problem with the keyboard.

I wouldn't suspect the transformer power supply, as it's putting out DC voltage (depending on the model keyboard).

There could be a problem with the jack physically.  Have you tried switching to another jack?  If you are using the L/R send, try the other jack if you aren't running it stereo.


Gene

[dave ingland]

Gene Simonalle wrote on Fri, 12 June 2009 09:10

Do you get the same sound problem with the headphone jack?  If you do, I suspect there is a problem with the keyboard. There could be a problem with the jack physically.  Have you tried switching to another jack?  If you are using the L/R send, try the other jack if you aren't running it stereo.

Sorry for not explaining in the original post that the headphones work fine unamplified from the keyboard. However, if I connect to the Roland combo amp from the headphone jack I get the same noise.

I have also tried connecting to left channel output and same sound occurs from there as well.

Thanks for the reply and I hope it helps figure out next steps to take.

[Kevin Maxwell AKA TheMAXX]

Have you tried another keyboard into this same amp? The simplest thing would be a problem with either the jack in the amp or the jacks in the keyboard. They can get dirty and that is the sound of a bad connection. Or there is a problem with the output of the keyboard or the input of the amp. I had a bass player who’s bass sounded all crackly. I cleaned the jack on his instrument and it cleaned up the sound right away.

If you tap on the keyboard or the amp near the connections does the noise change?

[dave ingland]

Kevin Maxwell AKA TheMAXX wrote on Sun, 14 June 2009 10:08

The simplest thing would be a problem with either the jack in the amp or the jacks in the keyboard. They can get dirty and that is the sound of a bad connection.

Anything special I need to clean the jack? Dry cloth or cotton swab or maybe rubbing alcohol? I have not thought of this so maybe I should explore this option since it's so easy

[Jeff Ekstrand]

Have you tried different cables? Could be a grounding problem. Are you for sure using a shielded instrument cable, or perhaps an unshielded 1/4" speaker cable???

[Kevin Maxwell AKA TheMAXX]

dave ingland wrote on Sun, 14 June 2009 15:06

Kevin Maxwell AKA TheMAXX wrote on Sun, 14 June 2009 10:08 The simplest thing would be a problem with either the jack in the amp or the jacks in the keyboard. They can get dirty and that is the sound of a bad connection. Anything special I need to clean the jack? Dry cloth or cotton swab or maybe rubbing alcohol? I have not thought of this so maybe I should explore this option since it's so easy

Depending on how dirty it is a cotton swab with contact cleaner might work but you have to be real careful you don’t loose pieces inside of the connector. I wouldn’t use rubbing alcohol it has oil in it. Isopropyl alcohol might work. Don’t use anything with acetone in it if there is any plastic anywhere in or near the connector it will eat it away.  

I use a 1/4" TRS burnishing tool like to one I link to below with some Caig DeoxIT on it. And I use a clean cloth to wipe down the tool. I do it a few times till the tool comes out clean.  

Also check out what Jeff said.

http://www.markertek.com/Cable-Management-Protection/Cable-A ssembly-Tools/VER-1.xhtml

[dave ingland]

I'll work on cleaning the contacts in the jack. However, the thing is that there is a crackling noise coming through the ampl even when the power to the keyboard is off. Also, no noise through the jack when using headphones.

I have tried multiple instrument cables (definitely *not* speaker cables) and have used different amps, connecting to different a/c source and using the same source. Even using a DI Box with ground lift switch, which has dampened the noise a little, but it is still very audible and annoying.

I'm wondering now if it may be the electronics on the board for the jacks. Are these prone to go out or seem like a reasonable answer to the crackling noise? Thanks for the help!

[Jeff Ekstrand]

I wouldn't say they're "prone" to failing (the solder points), but I have seen them go out. This mostly happens when the connections are not cared for, and usually only in extreme circumstances.

If the connectors are ever cranked one way or another, and this is done repeatedly, it can crack the solder connection on the PC board inside the keyboard. Sometimes it only takes one time, others can go years of abuse.

But I've never seen a well-cared-for keyboard connection go bad in an unreasonable time frame. Unless you're dealing with a keyboard from the early to mid eighties ("It's the final count-down... nananana, nanananana...), I would take a look at how your musicians treat the gear, and see if this could potentially be the cause.

[dave ingland]

After going through and cleaning the jacks, re-soldering some areas on the jack board, changing cables, etc. it turned out that the culprit was the power supply. On a whim, I changed it out and the crackling sound disappeared!

As it's a cheap and easy fix, I'd recommend others start here first unless it is an obvious low level hum that signifies a ground loop.

[Kevin Maxwell AKA TheMAXX]

dave ingland wrote on Mon, 22 June 2009 18:41

After going through and cleaning the jacks, re-soldering some areas on the jack board, changing cables, etc. it turned out that the culprit was the power supply. On a whim, I changed it out and the crackling sound disappeared! As it's a cheap and easy fix, I'd recommend others start here first unless it is an obvious low level hum that signifies a ground loop.

Thank you for following thru and telling us what the problem was. It is this kind of thing that can help other people.

When I saw that you said in one of your posts “However, the thing is that there is a crackling noise coming through the ampl even when the power to the keyboard is off.” I wanted to reply to that but I was so busy working I didn’t have time to respond. That was definitely a major red flag that it wasn’t the keyboard itself. I am glad you got it fixed.

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