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.