Excessive hum



  • I was excited to get my Spark on Monday and finally had time to try it yesterday. Wondering if anyone else is experiencing excessixe noise (hum). None of my other amps have any problems, I tried resetting a couple of times and no luck, I hooked up a HumX and thought it cut it down slightly but I was wrong. The tap button stays blinking and the first preset light is on. It gets much louder as you select 2,3 qnd 4.
    I was very disappointed with the quality of the power supply. Surprise that there was no ground and the insufficient guage of the wiring.
    If anyone has any suggestions I would appreciate it. I hope I don't have to return it after such anticipation.

    Thanks



  • Sounds like a bum amp. I would get it replaced.



  • @diegofiorillo-uk
    Yeah, I wrote support. We'll see. I'm not sure if it's worth going through the wait again...I’ve got a Roland ac30 that works really well for a practice amp, etc. and sounds great. I really wanted to like this but it's unusable. I'm hoping there's a setting I'm missing.



  • @richchaffee said in Excessive hum:

    @diegofiorillo-uk
    Yeah, I wrote support. We'll see. I'm not sure if it's worth going through the wait again...I’ve got a Roland ac30 that works really well for a practice amp, etc. and sounds great. I really wanted to like this but it's unusable. I'm hoping there's a setting I'm missing.

    gotta be something.


  • Moderator

    @richchaffee Hi, have you sent us a ticket? https://help.positivegrid.com/hc/en-us/requests/new, thank you



  • @mike I sent an email to support from the web site. I'll do this, too. Thanks



  • I had an excessive hum too that went away when I touched the guitar strings. It looks like it might have been related to the power socket I had plugged it in to because I have now moved it to a tower of sockets and the hum has gone. Mine also was particularly bad on presets 2,3 and 4.

    Hope you get it sorted.



  • Confirmed. I preordered and received two amps, both have same hum issue. I suspect the power supply and or an input grounding issue. I tried a HumX, and a proper isolation transformer with no improvement. I have many other tube and solid state amps that have no similar issues in my house. Tried several guitars, an EMG equipped guitar is only one that does not exhibit issue. (Internally grounded)

    Also creates terrible ground loops when used in conjunction with any number of other amps via an EQD Swiss Things or the stereo output of Boss MS-3.

    Noise gate hides issue.



  • @treeolyfe Hi, I have seen some patches with some hum, but have managed to resolve this. I really don't like the noise gate and tend to have it turned off. Where are you based? I'm in the UK, so wonder if you are right about it being power supply issues.



  • USA use 110v 60hz,
    they do have greater grounding issues in older neighbourhoods. .
    UK, Austrasia etc use 220/240v 50hz and grounding issues are less common, unless it's a faulty product.
    I'd try a different power adaptor for the spark and see if it helps.
    But few would have a 19v dc supply adaptor lying around, no point using your standard boss 9v dc one.
    And don't plug those digitech 9v ac ones in there either please.
    I'd first try plugging nothing else on that circuit, to isolate the offending item.
    I haven't received mine yet, so I don't know if it's the dc power unit supplied is at fault.
    from the pics online I see it has a 19v dc 2.5 amp input socket, but doesn't show polarity... which is more in the laptop or printer power supply range than normal muso adaptors.



  • @tuck60 I'm in the US. How did you resolve it?



  • @treeolyfe HI - did you create a ticket? I did and haven't heard back. I also sent an email to support.



  • @richchaffee Hi, Sorry for the delayed reply. I found that most of the patches that had excessive hum were on just a couple of amps. It was odd as I used the same set up (guitar, cable and plugged into the same power socket) with a Blackstar and Line 6 without any hum. So I guessed that it was the amp models themselves (although have never had a problem with PG AMP2 or FX running from my iPhone into an amp) as it only happened in a couple of amp models.
    I created/modified a couple of patches with these amps and played around with the gain and volume as well as the tone controls until I could find a setting that had a similar overdriven sound but with less hum. The power supply to the amp is in it's own isolated socket which has helped.
    I don't know if being in the UK and the power makes a difference.



  • I just received my Spark (USA) a couple of days ago and I am experiencing the same hum issue. Acoustic, Channel 1.......touch the metal on the patch cord and it stops. Sent an email to PG and they said they would send me another power supply (that's gonna be another 6 months). So, I purchased another supply, same voltage, amps, etc, but this one has a ground. NO LUCK. This has to be an internal design problem. Just wish this wasn't so as it's a major pain. I expect some on high gain, but from a Taylor 214CE, acoustic selected, and the "clean channel" 1.......goodness. Problems.......



  • Hi Guys!
    I got mine two day ago after what i would call a really long wait.
    The issue with hum and crackling noise when slightly touching the strings is definitely a grounding problem. The (lets say not sooo good) switching power supply has no ground connection and thats why hum and buzz can't be eliminated. it is goine when touching the (grounded) strings strong enaugh but whenever you lift the fingers for changing chords etc. it is back again and when sliding along the strings with just a soft touch it makes bad crackling noises.
    I think i solved the problem by using an extra wire tho connect the amps ground to to the ground of my AC socket. This problem wouldn't exist if the powersupply was one with transformer and a plug with groud connection. Now i'm really happy with the sound. Grounded strings don't make sense if there is no groundconnection on the amp!
    I'm kind of astonished that no one from PG realised it before selling that product.



  • yes in this day and age, it's unbelievable they didnt sort this out at design stage...



  • Count me in as another hum victim. USA. I'd be willing to get a grounded power supply on my own dime - anyone have the ID and OD of the connector on that?

    Of course, a shame to have to. I do not have hum on any of my other amps to speak of, it is unique to the Spark, thus far.



  • I received my amp (UK) 2 days ago. Big hum and buzz issues - some are so bad that the noise is louder than the actual notes played!

    There are actually 2 different components to the noise I am experiencing. One is what I would describe as a sort of "authentic" amp noise you get when the gain is cranked a bit, but on a regular amp would be so much lower than the actual guitar sound that you couldn't hear it when playing. I don't mind this so much as it gives a sort of added realism, but it is a bit too loud on the Spark and you can hear it to some extent when playing at moderate levels on headphones. Using the noise gate definitely helps but it does affect the sound and the 'feel' when playing.

    The other is more of a grounding issue and can be very loud unless the USB is plugged into a grounded laptop, which completely eliminates that buzz but it's far from an ideal permanent solution.

    I submitted a support ticket and got a really quick response with an update to the latest firmware (I had already updated as soon as I got the amp but this version I was sent was newer - 1.1.3.18). Things do seem a bit better now but I need to test more extensively. The grounding issue has not gone away however so I can only conclude this must be a physical problem that can't be solved via software and will presumably need a different power supply.



  • Same to me. Buzzing and ground issues disappear when touching the strings. Would love to see a hardware-Tweak. It seems badly grounded. I opened the case and think there is room for improvement.1_1591341957452_P6051740_small.jpg 0_1591341957448_P6051738_small.jpg



  • Update: my issues seem to be resolved. After getting rather frustrated after playing with electric, acoustic and bass, all with noise, hiss and hum so loud that it was practically unplayable, I was getting ready to send it back. Using the volume pot was impossible - the noise was bad enough at full volume but rolling it back a little was excruciating! Unbelievable levels of noise.

    So last resort I tried swapping my guitar lead (3rd different lead). Ground loop was suddenly reduced to perfectly acceptable levels and all the other hiss and noise had gone. Even high gain amps were ok with the noise only as you would expect.

    So the first 2 leads I tried were causing issues. I have used these with other amps and DI into various recording interfaces with no problems, so I don't think the leads are dodgy, but for some reason the Spark doesn't like them. They are perhaps of lower quality than the one that works though.

    Anyone with issues I would recommend trying the best quality cable you have and see if that helps.