Amp Noise (Updated)

[The amazing Phil]

Ok, so aside from 60 cycle hum, what makes amps noisey as noisey can get? Can a problem with the wiring in a house be responsible? I tried both my amps in 3 places through the house and they were both pretty noise, the Laney I can understand being noisey, but the Ashdown was too and I think it may be a problem with the grounding in the amp, but I just want to be sure it's not something my house is doing. I don't live near any powerlines, but there's an electricity substation about 150 yards from me. Could that do anything?

[Ratrod]

Could be anything. Bad earth wiring, dimmer switches, neon signs. Try your amp somewhere else. If it doesn't hum, you can at least rule out that it's an amp problem.

[HJM]

Hum and noise is all part of the fun....does it hum with no guitar or lead plugged in?

[The amazing Phil]

There's a lot of noise with everything turned down sadly,the laney just goes dead quiet, but the ashdown was still noisey, and even on the landing plugged straight into the wall, no extension sockets or any neon signs, it still made noise. Like a buzz.

[HJM]

COuld be a vlave, but take it to another house first

[Bob Johnson]

First off it'll be 50Hz hum if anything. 60Hz is reserved for less enlightened locations like the US.
Dimmer switches give off loads of radio frequency interference (RFI) so do neon lights. Ground loops caused by plugging the amp into one socket and a power supply for a stomp box or effects rig into another socket can increase mains hum. If you try lifting the ground from your mains connection, either at the plug or the amp, and the hum stops you may have an earth problem in your house or with one of the appliances in your house. Digital upstream stuff can also create problems with older valve amps. My son's line six POD xt pro will not work without loads of mains hum with my Traynor (1974 valve job) without lifting the ground on one of them, even though the house has been thoroughly checked for ground and neutral line potential. Close proximetry of the pickups (mainly single coils) to the amp will also pick up RFI.

[HJM]

Bob have I read that right??........that's not really that safe......I guess it's OK as a test...but other wise I'd have to say leave that earth where it is!!  :lol:

I've got my PAT (electrical test) head on now!! :P

A lot of amps have poor internal deisgn, leading to earth loops between the different stages inside th amp - that's pretty common. It is also possible you're getting a tone of EMI from the substation, although it's not that close.

Switchmode PSUs are evil - they put loads of noise down the mains, hissing spitting wierdness.

BTW what's the Ashdown??

Bob - feel free to argue with me..... 8)

[Bob Johnson]

You're absolutely right HJM, I should have qualified the advice by saying just lift the ground as a test (and be bloody careful while doing it) to establish where the issue lies. I thought it was implicit in the note but having re-read it I'll own up to the error.

Apologies one and all.

[chrisola]

Bobs trying to kill us all!!! :P

my Line6 guitar port hums like a bitch, REALLY REALLY bad on some patches... it seems to be the cable i'm using as it doesnt matter if my guitats plugged in or not.. just constant really loud HMMMMMMMMMMMMMM

Some patches theres none though... does the podxt\guitarport model hum aswell as amps? :P

[indysmith]

My buzz usually comes from my brother's dimmer switch....GRRR!!! I'm gonna change it for a propper switch when he's out

[The amazing Phil]

Well it's an Ashdown Essex Blonde which is a Matamp C7 in disguise, so I really doubt it's a design flaw. I know about the potential for groundloops with your effects plugged into different mains soces courtesy of aPeter Cornish interview I read not long ago, the amp made noise (UPS took it to amp-hospital for me) when there was nothing plugged in and everything was down, the Laney I have is next to inaudible in this situation.

So Bob, messing with the lifting the ground, is this before or after I jam a fork in a socket?? :lol:

[HJM]

You're absolutely right HJM, I should have qualified the advice by saying just lift the ground as a test (and be bloody careful while doing it) to establish where the issue lies. I thought it was implicit in the note but having re-read it I'll own up to the error.

Apologies one and all.

I thought that's what you meant...... :lol:

You wouldn't believe some of the things I've come accross........once somebody had removed the earth bond inside the amp to cure a loop!


The C7 is pretty quiet usually, and there's a lot of filtering in it to rid it of mains noise, it is possible though. If it's a Matamp made one I'd be suprised if there's a fault.......

[Bob Johnson]

The really bad hum I was refering to; POD XT Pro and Traynor YGL3, is not evident with any other amp we (my kids and I) have in the house. The valve amp the XT Pro is normally used with is a Peavey Ultratube and that's really quiet even on the same section of ring main. The ground lift switch (pre-amp only) on the Traynor makes no difference what-so-ever but lifting the ground on the XT pro mains plug, TEMPORARILY, stops it completely.

Bloody mystery; well it is to me. :oops:

[HJM]

Very odd......could be down to mains filtering on the Traynor, perhaps there's more in he Peavey and that smooths it out - than again that's just a stab in the dark!

[The amazing Phil]

Well Soundcontrol rang me, and they say that the people at the service center can't find anything wrong with it, I'm a bit pissed off about this to be honest.

If I can tell there's way too much hiss, the guys at soundcontrol say there's too much, the guy I rang at Ashdown says there should be next to none, and the Guitarist review said they had to check the LED to see if it's on...then surely the service center should recognise something is wrong, right?

I mean it's not $%&#ing rocket science. I'm gonna have to rattle some sabres and tell someone off tomorrow, somebody's obviously done a half assed job of trying to diagnose what's wrong.

Tell off I say!