• Registered: 2011-06-23
  • Posts: 72

Topic: Bi Amp buzz issue

I have noticed when I run my Vox ac30 and my Marshall JCM 800 together I get a buzz coming out of  the Vox.  It doesn't happen when its on its own just with the Marshall.

Any tips on how to fix this.  The cheaper the better.

Amps: Marshall JCM 800, Marshall 1987 X Plexi, Vox AC-30, Ceriaton ODS HRM, Fender Bassman
Guitars: Gibson Les Paul's(Standard, Classic, and Studio)Es 125 T, Fender Strats, Telies, Wasburn Idol Pro
FX's: BOSS TU-2, Ibanez TS-808, TS-9, Dunlap 535Q Cry Baby, Fulltone OCD, Full drive 2, Supa Trem, Rat, Whirlwind Phaser, MXR Micro Chorus, Digatech Whammy, Line 6 DL4, Holly grail 2,Wampler Ego,Pinical
  • From: Ridgeland, MS
  • Registered: 2009-08-12
  • Posts: 1,248

Re: Bi Amp buzz issue

If you use a Lehle or Voodoo Labs switcher, they have isolated transformers to eliminate ground loops. I believe some of the Radial models have this as well.

  • Registered: 2006-12-27
  • Posts: 42

Re: Bi Amp buzz issue

Two things...  Are you in the USA or abroad?   If you are in USA a simple Home Depot ground lift will sort out the buzz..   Its basically a three to two prong conversion..  Start with the vox.   If you are in the UK or abroad then I would look into a UK style ground lift..  a piece of plastic that they sell to lift the earth..  In Europe I use electrical tape and a strip of plastic to cover the ground strip in the ICD cable.   Be careful and ALWAYS wear shoes..  That will keep you from having a moment of zen with 120-240 volts...
Joe B

  • From: York, PA
  • Registered: 2010-08-27
  • Posts: 1,749

Re: Bi Amp buzz issue

If you can't plug each amp into a separate outlet that each run to a separate breaker line, the 3 into 2 prong adapters from the hardware stores DO usually work.

AT YOUR OWN RISK:  I've also posted this trick before on here, I know its not the safest but I've done it plenty of times with no trouble. If you're using a ground lift with one amp and still having noise: On a 2 prong adapter, one of the ends is wider than the other. Take a pair of dyke cutters and, with a hammer if necessary, take some width off the wide one. Then plug it into the outlet UPSIDE down. You'll have to trim wider prong in order to do this. AGAIN, it works, but do so at your own risk. I've done it plenty of times.

OR, if you spend a few bucks and get a power conditioner that has isolated outlets on the rear, you can plug 2: 100watt heads into it plus all your effects, pedalboard and have no noise.  I have the Monster Power Conditioner 2500 model and its great, but I still use a ground lift. ZERO NOISE! Paid about 130-140, price matched at GC.

  • Jon
  • Bronze Member
  • Offline
  • Registered: 2007-03-19
  • Posts: 39

Re: Bi Amp buzz issue

helrazr84 wrote:

Take a pair of dyke cutters

You need CUTTERS to separate them?!?!?! I would've thought just a bucket of cold water would do the trick!

  • ken
  • ken
  • Titanium
  • Offline
  • From: Orlando, FL
  • Registered: 2007-05-28
  • Posts: 949

Re: Bi Amp buzz issue

Jon wrote:
helrazr84 wrote:

Take a pair of dyke cutters

You need CUTTERS to separate them?!?!?! I would've thought just a bucket of cold water would do the trick!

  yikes

  • From: N.Wales, UK
  • Registered: 2009-03-06
  • Posts: 2,183

Re: Bi Amp buzz issue

I don't like the idea of all the 'DIY' methods...even from JB.

When I had a multi-amp setup...I used a Radial JX2 Pro Switchbone. It is a killer piece. Built well...ground lift...mid-boost...etc etc. Genius. The only thing I'd use from now on. I don't trust my rubber shoes!
http://www.tonebone.com/tb-switchbone.htm

  • Registered: 2011-06-23
  • Posts: 72

Re: Bi Amp buzz issue

thanks the 2 prong trick worked

Amps: Marshall JCM 800, Marshall 1987 X Plexi, Vox AC-30, Ceriaton ODS HRM, Fender Bassman
Guitars: Gibson Les Paul's(Standard, Classic, and Studio)Es 125 T, Fender Strats, Telies, Wasburn Idol Pro
FX's: BOSS TU-2, Ibanez TS-808, TS-9, Dunlap 535Q Cry Baby, Fulltone OCD, Full drive 2, Supa Trem, Rat, Whirlwind Phaser, MXR Micro Chorus, Digatech Whammy, Line 6 DL4, Holly grail 2,Wampler Ego,Pinical
  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: Bi Amp buzz issue

Ok I just played a theatre in northerm michigan. Built in the early 1900's and power was not native to the building. All the amps, lights, etc. were plugged into a small amount of outlets on each side of the large stage. My early 90's Peavey Classic 30 amps was not liking it.

It was a hummy amp to begin with, but the old school soundguys were looking at it in disgust. They weren't having it. I didn't know what to tell them. I mean, it's plugged into a million different extension cords and power strips, what do you expect? We ran a line for just my amp... and it still hummed to beat hell. The solution? and i've had this amp and its issue for years. They brought out a 3 prong to 2 prong conversion plug ground lift. That make the amp quiet as a lamb. I couldn't believe it. So I might have to run that on my amp full time now. Even though it's a "safety hazard" I'll be sure to wear shoes everytime.

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool
  • Registered: 2010-12-06
  • Posts: 122

Re: Bi Amp buzz issue

Simple solution, amps only hum when you're not playing.

  • Registered: 2007-11-22
  • Posts: 358

Re: Bi Amp buzz issue

There is a small device you can buy for a couple of bucks at most hardware stores that has small lights on it and it is designed to check if an outlet is grounded or not simply by plugging it in. It fits in your pocket easily and worth it's weight in gold if you ask me.

Also a question for the guys who play a lot using two amps. Wouldn't plugging both amps into the same power source eliminate the buzz, much like plugging a pedal into the same outlet as the amp eliminates buzz?