Amps with a background hissing

**Torito** · 01-05-2013, 08:07 PM

Hi folks, I'm not a gear expert at all (or just not an expert in anything, period), hence this thread.

I have two small amps, a Roland Cube 15XL and a Behringer V-Tone GM108. Both of them have a hissing tone when they're on but I'm not playing. When I'm playing, or if I just put my hand over the strings, the annoying hissing is significantly reduced.

Is this normal? Do all amps at this price range ("affordable") come with a background buzzing as default?

OK, any comments appreciated.

Thanks

**barrymclark** · 01-05-2013, 08:22 PM

Is it a hiss or a buzz? I ask that sounds like grounding on the guitar.

**Torito** · 01-05-2013, 08:46 PM

Humm, I'm not sure what the difference is, I think it's more of a low level buzz.

I don't think is the guitar though, they do it with other guitars I've plugged in too.

**barrymclark** · 01-05-2013, 08:57 PM

Originally Posted by Torito

Humm, I'm not sure what the difference is, I think it's more of a low level buzz.

I don't think is the guitar though, they do it with other guitars I've plugged in too.

Well, it reducing when you touch the strings is the tell-tale sign. Real common on passive-equipped guitars.

**Torito** · 01-05-2013, 09:28 PM

Thanks, Barry. Is there any solution for this?

**GNAPPI** · 01-05-2013, 09:33 PM

If the sound" mostly goes away when you touch the strings, that's pretty normal. One you play you do not hear it do you?

**barrymclark** · 01-05-2013, 09:41 PM

Originally Posted by Torito

Thanks, Barry. Is there any solution for this?

As GNAPPI put it, this is very normal. On solid-body guitars, there are shielding techniques that reduce the noise. Not sure what you would do with a hollow-body.

**Torito** · 01-06-2013, 04:43 AM

OK, I get the idea. So I just have to get used to it, it's pretty normal.

I thought this could be the result of buying entry level amps...

By the way, do amps with valves also produce this background buzzing?

**cosmic gumbo** · 01-06-2013, 05:59 AM

Once when we wuz doin' a gig at Wally's Gator Ranch and BBQ, Curtis heard a loud hiss comin' frum his amp and a viper jumped out at him.

**oldane** · 01-06-2013, 06:01 AM

Originally Posted by Torito

OK, I get the idea. So I just have to get used to it, it's pretty normal.

I thought this could be the result of buying entry level amps...

By the way, do amps with valves also produce this background buzzing?

Usualy, it's not the amp which produces the hum. It's the guitar (the pickups and the harness) and the cable between the guitar and the amp which picks up the hum from the electrical installations in the surroundings. But of course, a badly shielded amp can also pick up hum. This is independent on tube/SS.

**ChrisDowning** · 01-06-2013, 07:22 AM

Yep its more guitar than amp. The cheaper the guitar, generally, the more interference you get becuase ofthe design and screening is poorer. ( like those stories about picking up taxi messages.) However you'll get a whole lot more background sounds from single coils - and the lower the impedence to more the interference - so my guitar loaded with SD Alnico 2 single coils with about 6ohm resistance get very noisey when near to any source - like neon lights, flurecent lights, the new energy saving lights, the TV, radio, phone, mobile - anything that has radio signals broadcast or live circuitry. That's why people swap these PUs for humbuckers that are nearer to silent (but sound more bassy - that's the downside).

Try your amp with a humbucker PU guitar and see if its silent then.

**Torito** · 01-06-2013, 09:02 AM

Thanks everyone for the comments.

I'm playing with a Ibanez PM35 with all factory defaults. Maybe anyone with the same gear can discuss whether he or she has the same problem?

**barrymclark** · 01-06-2013, 10:26 AM

Originally Posted by Torito

Thanks everyone for the comments.

I'm playing with a Ibanez PM35 with all factory defaults. Maybe anyone with the same gear can discuss whether he or she has the same problem?

Like them or not, I think anyone being completely honest will agree that Ibanez makes solid, solid guitars from the top of their price range to the bottom. Surely an issue slips out from time to time (although I have never seen one), but I'd easily put Ibanez at the top of the reliability list.

**oldane** · 01-06-2013, 11:18 AM

It's not related to a particular guitar model. It's generic with almost all hollow body guitars. Solid body guitars with closed cavities for pickups and wiring can be shielded rather effectively with say copper foil (though it's rare to see it in factory made guitars). Effective shilding is harder on hollowbodies where the wiring (and the solderings) is hanging free inside the box.

My old Gibson ES175 has quite some hum when the strings or metal parts are not touched - despite having humbuckers and shielded pots - and so has my other hollowbodies too. The one with the least hum - despite a single coil pickup - is a Warmoth partscaster (Strat body) I put together myself. With that one, I took the time to shield all cavities and the underside of the pickguard with copper foil. But even then, there is still a little bit of hum when not touching the metal parts.

I like that hum as little as you do, but I think we have to realize that it's a fact of life with electric guitars. If the hum is only there - or is much more pronounced - when not touching the strings, a noise gate dialled in at a conservative setting, which removes the hum but nothing more, can be a solution. I use a Boss NS-2 which works OK for me and doesn't affect the tone as far as I can hear. I put it between the guitar and the amp input.

Mind you, I have been talking about hum (sounding like 50Hz "brrrr"). Hiss (sounding like white noise "shssss") is another thing. I have yet to see a solid state amp, which doesn't hiss a little. If you use a speaker with a tweeter, the hiss is heard more. Usually tube amps don't hiss. Instead they more often than not hum a little.

**barrymclark** · 01-06-2013, 11:25 AM

Originally Posted by oldane

It's not related to a particular guitar model. It's generic with almost all hollow body guitars. Solid body guitars with closed cavities for pickups and wiring can be shielded rather effectively with say copper foil (though it's rare to see it in factory made guitars). Effective shilding is harder on hollowbodies where the wiring (and the solderings) is hanging free inside the box.

My old Gibson ES175 has quite some hum when the strings or metal parts are not touched - despite having humbuckers and shielded pots - and so has my other hollowbodies too. The one with the least hum - despite a single coil pickup - is a Warmoth partscaster (Strat body) I put together myself with which I took the time to shield all cavities and the underside of the pickguard with copper foil. But even then, there is still a little bit of hum when not touching the metal parts.

I like that hum as little as you do, but I think we have to realize that it's a fact of life with electric guitars. If the hum is only there - or is much more pronounced - when not touching the strings, a noise gate dialled in at a conservative setting, which removes the hum but nothing more, can be a solution. I use a Boss NS-2 which works OK for me and doesn't affect the tone as far as I can hear. I put it between the guitar and the amp input.

Good advice from oldane. I can't think of when I am not touching the strings when I play. I guess it is a habit I developed over decades and don't even notice that I do it anymore. I also did it to make sure I didn't have any errant ringing strings.

**oldane** · 01-06-2013, 11:41 AM

Originally Posted by barrymclark

I can't think of when I am not touching the strings when I play.

I don't touch the strings if I use a music stand and turn sheets between numbers.

**PTChristopher** · 01-06-2013, 12:13 PM

All this string touching talk reminds me of when grounded strings were really a very exciting thing.

Even at our low US 120 VAC, the lack of consistent amp and PA grounding with equipment in wide use well into the 80's made for a very good chance that there was 120 VAC between your strings and your microphone or you and the bass player, or you and a grounded anything in the building (steel countertop, water pipe, heating, etc.).

We would set up then go around touching everything, including other instruments and players, to see if anyone was fixing to arc. The classic was a jolt from a mike as your lips touched it during your "Ooooooh Baybeeeeee!" background vocal. It was pretty exciting.

For a while Les Pauls were made with ungrounded strings and a can that covered the 4 pots. It was not a perfect system in a high-gain distortion environment even with all the shielding, so even though Gibson would frown upon it - many got a ground wire added. The rear cover "can" from this shielded system was used as an ashtray back in those days when they were around, and most guys in a shop smoked still.

If you have an older amp, REALLY get the power cord changed and the AC supply grounding set up to modern standards. It is fast, easy to do, and really can save you from what is often a nuisance, but potentially a serious danger. ("Potentially" - get it? Like voltage,... a very weak joke.)

I have no idea in what year amps were grounded safely. I made my 2X 6L6 amp in 1981 and it is grounded to modern standards - so I am assuming that I was only doing what was commonly in commercial practice by then.

But there are lots of Bandmaster and Dual Showman heads out there ready to fry something.

Still off-topic: A hiss is from what is called "thermal-noise" and indeed is very commonly heard in most solid state pre-amps. Some have a great deal of thermal noise, and in such a case it is well worth trying to re-balance your gain vs. overall EQ settings vs. master volume. Often you can get the same eventual sound and volume with less total thermal noise coming through.

In my opinion.

Chris

**oldane** · 01-06-2013, 12:28 PM

Originally Posted by PTChristopher

We would set up then go around touching everything, including other instruments and players, to see if anyone was fixing to arc. The classic was a jolt from a mike as your lips touched it during your "Ooooooh Baybeeeeee!" background vocal. It was pretty exciting.

Very exciting. They still talk about when Keith Richards was knocked out cold by an electric shock from a microphone stand. But being Mr. Indestructable, as he is, he made it.

**barrymclark** · 01-06-2013, 12:36 PM

Yep. Seen people drop on stage from a good grab. Didn't kill them but literally put them on the floor. I've had my lips go numb but no more. Haha. Good times.

**Gibouille** · 01-08-2013, 05:34 AM

I have a vox mini 3

It does a sound even when not playing (don't ow if buzz or hissing but it is basically white noise)
Gets slightly better when I use a bigger heavier better voltage transformer than the stock one.
Gets slightly better when toouching the strings

but one thing is WEIRD

When I plug in a jack in the headphone out the speaker becomes inactive, it won't make sound if I play but the goddam white noise is STILL THERE.... coming from the inactive speaker.

Also I don't get any soind in my headset but if I plug the headphones-out to a mixing table, there I can hear my guitar but with plenty of this white noise...

Who wants an almost new Vox mini 3 ?

By the way my avatar shows my kid testing my headset, she like it. She's a fan of Benny Breau and Barney Kessel

**ooglybong** · 01-08-2013, 09:10 AM

Originally Posted by oldane

Hiss (sounding like white noise "shssss") is another thing. I have yet to see a solid state amp, which doesn't hiss a little. If you use a speaker with a tweeter, the hiss is heard more. Usually tube amps don't hiss. Instead they more often than not hum a little.

Hisssss... I saw this thread's title and immediately thought the topic was going to end up being the Roland JC line of amps. Familiar topic, I know, but I was reminded this weekend in a store when trying out an archtop, asked for a loud SS amp, and they rolled out a funky old battle-scarred JC 120. Turned it on... yup... there's that infamous JC Hiss. I had a JC77 for years and traded it. Great amp, but with some really noticeable hiss, even with it set to zero.

Surprised to be hearing my Jazzmaster UltraLight having a very small amount of hiss, too (but nothing at all like the JC). Noticed it a bit more lately with it in just the right position and turned up a bit more; of course, this is only heard in my otherwise quiet living room, and then it's more of a 'can I hear it?' scenario where I'm now looking for it. (Stop listening for hiss, man... shut up an' play yer guitar!)

Yeah, I think that SS amps all tend to hiss just a little.

**ooglybong** · 01-08-2013, 09:17 AM

Originally Posted by barrymclark

I can't think of when I am not touching the strings when I play.

Originally Posted by oldane

I don't touch the strings if I use a music stand and turn sheets between numbers.

(Speaking here of grounding noise, not SS background amp hiss...) Me neither, but don't you then instinctively roll the guitar volume to zero at that point? That should kill any grounding noise, IIRC.

**Gibouille** · 01-08-2013, 09:45 AM

Originally Posted by ooglybong

Originally Posted by barrymclark

I can't think of when I am not touching the strings when I play.

There are a lot of times I'm not touching the strings (but I'm a beginner)

When I'm reading the sheet and wondering what's the best fingering,
When I'm reading the pedagogical resource (by Jamie Holroyd for example) and sometimes writing annotations to those documents
When I'm fiddling with pedals and sometimes even with the pedal's manual (doing this a lot at the moment with my looper)
When I'm actually taking notes wether with a pen or with software like Guitar pro or Sibellius
When I'm listening to recorded music to grab ideas

**pingu** · 01-08-2013, 10:22 AM

but one thing is WEIRD

When I plug in a jack in the headphone out the speaker becomes inactive, it won't make sound if I play but the goddam white noise is STILL THERE.... coming from the inactive speaker.

the headfone jack takes the op from the pre-amp
so you're still hearing the power-amp hiss through the speaker

**ChrisDowning** · 01-08-2013, 11:22 AM

Check the amp is grounded properly and has a three core cable and is correctly wired. In Europe a lot of these 13 amp plugs are retro fitted. Check the strings and bridge are grounded. Check your house is correctly grounded - try the amp in another venue and see if it still hisses. Isolate whether its the guitar or amp - try another single coil guitar in the amp - same / not? Now you've covered the basics and you are into taking something in for a service.