Just received a Genz Benz Contour 500 and it has a bad grounding issue

Discussion in 'Amps [BG]' started by phishaholik, Feb 19, 2014.


  1. phishaholik

    phishaholik Supporting Member

    Joined:
    Aug 20, 2005
    Messages:
    1,614
    Location:
    Manassas, VA
    I just received the amp yesterday from Pro Audio Star. I plugged the bad boy in and it's buzzing like crazy if I don't have my hands completely on the strings. It still buzzes when just the side of my finger is on the strings. If I don't have my hands on the strings and get them anywhere near the pickups the buzzing is louder than the bass and it's un-usable.

    I LOVE the tone and I'm amazed by how good it sounds. I love everything about it but the grounding issue. The amp sounds flat out fantastic and the EQ is fantastic. It's very, very loud and like most Genz Benz stuff, you can turn it up almost all the way and get usable volume.

    I already contacted Pro Audio Star, but haven't heard back yet. I don't know how good their return policy is and I'm certainly not going to pay return shipping to Brooklyn. I already tried different basses, I used my Fodera and my Sadowsky which have no shielding issues, as well as different outlets and power chords.

    Anything else before I send it back?


    Michael
     
  2. Tractorr

    Tractorr Supporting Member

    Joined:
    Aug 23, 2011
    Messages:
    1,226
    Media:
    4
    Location:
    Philadelphia
    A) Do other amps have the same problem wherever you are playing? Have you played it at other locations?

    B) Have you recently plugged in any other new electronic devices?


    Not saying it isn't the amp but best to trouble shoot all possibilities before going through the hassle of a return.
     
  3. phishaholik

    phishaholik Supporting Member

    Joined:
    Aug 20, 2005
    Messages:
    1,614
    Location:
    Manassas, VA
    I'm actually looking for trouble shooting advice. Thanks!

    I don't have any buzzing issues with any other amps I have right now. I will say, one of the outlets in another room went out a couple days ago and knocked the rest of the outlets out as well. It's a different room on the same floor, but I know nothing about electricity.

    I tried different outlets in the same room, but not a different place yet. I haven't plugged any new devices in yet, but there was nothing on but an alarm clock on the other side of the room.



    Thanks again!

    Michael
     
  4. Tractorr

    Tractorr Supporting Member

    Joined:
    Aug 23, 2011
    Messages:
    1,226
    Media:
    4
    Location:
    Philadelphia
    I am by no means an electrician but I have heard of really weird stuff causing ground hums. I would check another amp in the exact same outlet and see if there are any issues. Then it likely isn't your electricity.
     
  5. Register to disable this ad
  6. phishaholik

    phishaholik Supporting Member

    Joined:
    Aug 20, 2005
    Messages:
    1,614
    Location:
    Manassas, VA
    Yeah, I've run other amps in that room just fine in the past, but not since the power in the other room went haywire. I'm going to try it at another house to make sure.

    Seems like Pro Audio Star's customer service is pretty good. I already received a shipping label from them. So, if it's still buzzing at a different house I'm just going to send it back tomorrow.


    Thanks again for your help,


    Michael
     
  7. agedhorse

    agedhorse Development Engineer-Mesa, Product Support-Genz Supporting Member

    Joined:
    Feb 12, 2006
    Messages:
    5,361
    Let's troubleshoot this logically...

    1. With nothing plugged into the amp's input jack, is the amp quiet (volume controls up or down)?

    2. With the bass plugged into the amp and the input volume on the amp down, is the amp quiet?

    3. Does the amp get noisy when you turn the volume control on the amp up?

    4. What happens when you turn the bass's volume control down.

    5. Have you tried a different bass AND cable? (you are using an instrument cable right?)

    From your description, it sounds like interference is getting into the pickup system on the bass and the amp is just doing it's job amplifing whatever signal is presented to the input jack (be it a bass signal or interference). The troubleshooting steps above will help determine what's going on.
     
  8. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Messages:
    10,820
    Location:
    New Zealand
    OP, you should listen to Agedhorse. We're lucky he has time for two jobs and us!
     
  9. phishaholik

    phishaholik Supporting Member

    Joined:
    Aug 20, 2005
    Messages:
    1,614
    Location:
    Manassas, VA

    Hi Agedhorse,

    Thanks for the reply, I was hoping you would chime in. I just did some more trouble shooting, but let me reply to your questions first.

    1. Yes, the amp is quiet when the volume is down or if the mute is on.

    2. If you are talking about the preamp volume after the gain knob, I did not try that.

    3. The volume of the buzzing does increase with the volumeof the amp.

    4. When I turn the basses volume control down, the amp is quiet.

    5. I did not try to use a different instrument cable.


    So, last night I brought the amp downstairs to try it in a different room. It did decrease the buzzing, but it's possible I was just sitting further from the amp. One thing though, when I used my MM Bongo, there was no buzz at all.

    Now I know that makes it sound like it's not the amp causing it, but the basses I used. The only thing about that, is I have never had the slightest bit of buzzing from either my Fodera (since I shielded it) or my Sadowsky through any other amp in the same house. They are both fully shielded and usually dead quiet. The buzzing when I use my Sadowsky is still crazy loud, especially if my hands are near the pickups but not touching the strings. I don't have this problem when I use my Mesa Walkabout.


    Thanks for the help!


    Michael
     
  10. agedhorse

    agedhorse Development Engineer-Mesa, Product Support-Genz Supporting Member

    Joined:
    Feb 12, 2006
    Messages:
    5,361
    Excellent, I would recommend having your bass checked over by a qualified tech. They will need to verify that the entire grounding system is intact, specifically that the bridge and strings are bonded to the output jack sleeve. I think this is where you will find the problem
     
  11. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Messages:
    13,856
    Location:
    Toronto Ontario Canada
    To add to the above, don't stand/sit too close to the amp head. The power transformer can induce a deal of noise into a bass.

    The above is premised on the amp having a PT and not a SMPS. :)
     
  12. Herbie Chesnutt

    Herbie Chesnutt Supporting Member

    Joined:
    Mar 19, 2010
    Messages:
    543
    Location:
    Highlands Ranch. Colorado
    This was a huge problem with a Fender combo amp I had. I just assumed my Jazz was a buzzy bugger until I upgraded to a new amp/cab and the buzz went away. It was a 'duh! moment for me. Totally worth a try. Does the buzz decrease the further away you get from the combo?

    Also too, my laptop gave me wicked buzz. Same deal as above.
     
  13. jeff7bass

    jeff7bass

    Joined:
    Apr 9, 2009
    Messages:
    2,782
    Single coil basses produce hum which on lesser amps might not be noticable but on more powerful amps becomes clear. Bad shielding is another culprit, also the bass. My drummer installed a few of those new energy saving bulbs in our rehearsal space and they produced buzz in both my guitar player's amp and mine. Took them out, buzz gone. I think Agedhorse is on to the culprit having a powerful, clean amp just makes it more apparent.
     
  14. phishaholik

    phishaholik Supporting Member

    Joined:
    Aug 20, 2005
    Messages:
    1,614
    Location:
    Manassas, VA
    Just wanted to give an update. Now that I've done some more trouble shooting, it's definitely not the amp. It seems that there is something wonky going on in my house. Sometimes my bass buzzes in that room, sometimes it doesn't. I tried another amp and got buzz in that room, but left it plugged into the same outlet and moved the amp into the next room and no buzz.


    Whatever the weirdness is, it's not the Contour. Happy day and great sounding amp!


    Thanks for all the trouble shooting advice guys!


    Michael
     

Share This Page