I' need help...running two amps.. cause thy Buzzzzzzzzzzzzzz

Don Mare · December 19th, 2003, 04:23 PM

Hey,
I've tried a "Y" cable and also going out of the Devile's pre-out..to the Blues Jr.. and the Buzz is too loud fer' the crowd..
any Eye-Dears how to overcome it?

0le FUZZY · December 19th, 2003, 04:46 PM

Outta faze A.C. power or bad patch cord are all I kin think of.

Mebby tew much gain???

Light dimmers in the area?

Jes guessin.

---0.F.---

TheGoodTexan · December 19th, 2003, 04:57 PM

If you're not singing into a microphone - try lifting the ground on one or both amps, using a simple 3 to 2 prong adapter.

WARNING - Do not do this if you're singing into a mircophone. Lifting the ground could cause a severe shock to the mouth, and possibly death - you don't want to play with electricty going through your body!

halouis · December 19th, 2003, 05:29 PM

thats a ground loop problem most likely!

try lifting the ground (using one of those grey 3 prong -> 2 prong adapters) on 1 of the amps power plug first to see if that fixes it. if so you know the answer. But it's not recommended to do this at gigs and such. so you'll need to use a gadget with isolated transformers.

I believe ebTech makes such a contraption.

Teleologist · December 19th, 2003, 05:56 PM

If the amps are daisy chained and you decide to lift an AC ground, leave the amp your guitar is plugged into grounded and lift the other one.

A better and safer way that usually works is to lift the shield connection on one end of the guitar cable that connects the amps. Try reversing this cable to see which way is quieter, then mark it so you don't accidently use it for something else. You can make up a special short cable like this and use it with a barrel connector and normal cable to get whatever length you want. Some pro-sound guys connect the shield at one end with a small cap(~.047uF) to reduce any AC line noise, but for a short guitar cord it's not usually necessary.

If all else fails, an isolation transformer(EbTech Hum-eliminator) will fix the problem.

Mike H. · December 19th, 2003, 05:58 PM

This is usually caused by a difference in ground potential when the amps are plugged into two different electrical outlets. Try plugging both amps into a single source. You still may need some sort of power conditioner if the electrical system is picking up stray noise. Neon lights, faulty ballasts from flouresents, etc. in the same electrical system can also cause buzzing.

Lyle Caldwell · December 19th, 2003, 06:18 PM

Lift the signal ground, as Teleologist suggests. Never lift the 120V ground on the amp's power cord. I don't care how many times you've done it, or how many people say to do it. You've been lucky, and they've been wrong. It's just damn stupid.

Tim Armstrong · December 19th, 2003, 07:37 PM

...run both amps off of a single power strip.

Also, let me ask: Are they modern amps with three-prong plugs? I hope so, since the older kind aren't anywhere near as safe!

Cheers, Tim

Silverface · December 19th, 2003, 07:44 PM

Quote:

I don't care how many times you've done it, or how many people say to do it. You've been lucky, and they've been wrong. It's just damn stupid.

Man, that is SO true! Microphone or or not - there are so many ways to die by touching things on a stage plugged into a non-grounded amp...because YOU become the ground. Your heart doesn't like that very much, and you die.

Lifting the ground at the power cord of either amp is dumb, dumb, dumb. Terrible, life-threatening advice...do NOT do it!

As recommended - the only positive, safe solution is to use an isolation transformer.

I can't believe people still recommend a ground lift!

Tim Bowen · December 19th, 2003, 11:23 PM

I was at a rehearsal about 10 years ago at an old house with electrical wiring that was probably installed during Warren G. Harding's Presidency. Recently acquired '52 RI into '65 bf Twin w/ a two pronger... had my left hand on the tele, & when I plugged in the instrument cable, I guess I completed a loop... holy smokes what a jolt of voltage... I could literally smell my hair burning & my heart was just about to jump out of my chest; I was completely powerless to do anything about it... a mate finally yanked the AC cord out of the wall... I don't know how long this went on, but I have no doubt I was within seconds of cardiac arrest, & am lucky to have lived to tell the tale... tele still strapped on, I stumbled out into the yard, barfed, fell right in it, & passed out. Okay, that's probably a little more information than you needed... but for years afterward, I would bat at electric guitars with the back of my hand before I'd pick 'em up...

okay...

Garden variety A/B boxes such as Morley, Whirlwind, etc. will not help ground loop hum. Nor will effects boxes with 2 outs... As already stated, isolated transformers are the ticket, & most ain't cheap... Lehle & Tonebone will work. Cheapest thing I'm aware of with isolated out is the Axess BS2 Splitter/Buffer, at about $100.00 - although the web page is no longer to be found, not sure if it's still available or not. The Ebtech HE-2 I don't get, because it is not intended for instrument level signals, but for line level. A buddy of mine tried placing it in line with his rig, & said it destroyed his tone - thin, weak, & attenuated. ??

http://www.audiomidi.com/common/cfm/...Product_ID=314

http://www.lehleusa.com/

http://www.tonebone.com/tbone-jx2.htm

Tim Bowen · December 19th, 2003, 11:45 PM

I think I might pick one of these up, looks like a better than average power strip.

http://qualityelectronics.net/fusssust.html

December 19th, 2003, 04:23 PM	#1 (permalink)
Don Mare Tele-Holic Join Date: Mar 2003 Location: CA. Posts: 534	I' need help...running two amps.. cause thy Buzzzzzzzzzzzzzz Hey, I've tried a "Y" cable and also going out of the Devile's pre-out..to the Blues Jr.. and the Buzz is too loud fer' the crowd.. any Eye-Dears how to overcome it?

December 19th, 2003, 04:46 PM	#2 (permalink)
0le FUZZY Doctor of Teleocity Join Date: Mar 2003 Location: Kolly-forn-knee-ya Posts: 10,001 6 Photos	` Outta faze A.C. power or bad patch cord are all I kin think of. Mebby tew much gain??? Light dimmers in the area? Jes guessin. ---0.F.---

December 19th, 2003, 05:56 PM	#5 (permalink)
Teleologist Tele-Meister Join Date: Nov 2003 Location: Chicago Posts: 382	If the amps are daisy chained and you decide to lift an AC ground, leave the amp your guitar is plugged into grounded and lift the other one. A better and safer way that usually works is to lift the shield connection on one end of the guitar cable that connects the amps. Try reversing this cable to see which way is quieter, then mark it so you don't accidently use it for something else. You can make up a special short cable like this and use it with a barrel connector and normal cable to get whatever length you want. Some pro-sound guys connect the shield at one end with a small cap(~.047uF) to reduce any AC line noise, but for a short guitar cord it's not usually necessary. If all else fails, an isolation transformer(EbTech Hum-eliminator) will fix the problem. __________________ Keep on Twangin'

December 19th, 2003, 06:18 PM	#7 (permalink)
Lyle Caldwell Tele-Holic Join Date: Mar 2003 Posts: 535	Lift the signal ground, as Teleologist suggests. Never lift the 120V ground on the amp's power cord. I don't care how many times you've done it, or how many people say to do it. You've been lucky, and they've been wrong. It's just damn stupid. __________________ "Everybody sings about Memphis, but nobody ever does anything about it."

December 19th, 2003, 07:37 PM	#8 (permalink)
Tim Armstrong Moderator Poster Extraordinaire Join Date: Mar 2003 Location: Berlin, Maryland, USA Age: 49 Posts: 9,678	You've probably already tried this, but... ...run both amps off of a single power strip. Also, let me ask: Are they modern amps with three-prong plugs? I hope so, since the older kind aren't anywhere near as safe! Cheers, Tim

December 19th, 2003, 05:29 PM	#4 (permalink)
halouis Tele-Afflicted Join Date: Mar 2003 Location: Virginia Posts: 1,404 7 Photos	thats a ground loop problem most likely! try lifting the ground (using one of those grey 3 prong -> 2 prong adapters) on 1 of the amps power plug first to see if that fixes it. if so you know the answer. But it's not recommended to do this at gigs and such. so you'll need to use a gadget with isolated transformers. I believe ebTech makes such a contraption.

December 19th, 2003, 05:58 PM	#6 (permalink)
Mike H. TDPRI Member Join Date: May 2003 Location: San Francisco Bay Area Age: 53 Posts: 96	This is usually caused by a difference in ground potential when the amps are plugged into two different electrical outlets. Try plugging both amps into a single source. You still may need some sort of power conditioner if the electrical system is picking up stray noise. Neon lights, faulty ballasts from flouresents, etc. in the same electrical system can also cause buzzing.

December 19th, 2003, 11:23 PM	#10 (permalink)
Tim Bowen Friend of Leo's Join Date: Mar 2003 Location: Atlanta, Georgia Age: 48 Posts: 3,321	The living dead checking in here... I was at a rehearsal about 10 years ago at an old house with electrical wiring that was probably installed during Warren G. Harding's Presidency. Recently acquired '52 RI into '65 bf Twin w/ a two pronger... had my left hand on the tele, & when I plugged in the instrument cable, I guess I completed a loop... holy smokes what a jolt of voltage... I could literally smell my hair burning & my heart was just about to jump out of my chest; I was completely powerless to do anything about it... a mate finally yanked the AC cord out of the wall... I don't know how long this went on, but I have no doubt I was within seconds of cardiac arrest, & am lucky to have lived to tell the tale... tele still strapped on, I stumbled out into the yard, barfed, fell right in it, & passed out. Okay, that's probably a little more information than you needed... but for years afterward, I would bat at electric guitars with the back of my hand before I'd pick 'em up... okay... Garden variety A/B boxes such as Morley, Whirlwind, etc. will not help ground loop hum. Nor will effects boxes with 2 outs... As already stated, isolated transformers are the ticket, & most ain't cheap... Lehle & Tonebone will work. Cheapest thing I'm aware of with isolated out is the Axess BS2 Splitter/Buffer, at about $100.00 - although the web page is no longer to be found, not sure if it's still available or not. The Ebtech HE-2 I don't get, because it is not intended for instrument level signals, but for line level. A buddy of mine tried placing it in line with his rig, & said it destroyed his tone - thin, weak, & attenuated. ?? http://www.audiomidi.com/common/cfm/...Product_ID=314 http://www.lehleusa.com/ http://www.tonebone.com/tbone-jx2.htm __________________ "Everyone is different in how they learn, but for me, it's turning the pegs and just playing." - BB

December 19th, 2003, 11:45 PM	#11 (permalink)
Tim Bowen Friend of Leo's Join Date: Mar 2003 Location: Atlanta, Georgia Age: 48 Posts: 3,321	I think I might pick one of these up, looks like a better than average power strip. http://qualityelectronics.net/fusssust.html __________________ "Everyone is different in how they learn, but for me, it's turning the pegs and just playing." - BB