Amp hum

[Hank-]

Do all tube amps have some amount of hum emitting from the speakers without a guitar plugged into them?
I mean with the gain at zero and master/channel volume at zero.

It's been bothering me for awhile, my laney lc50 may have developed a problem lately. I've eliminated tubes (have 10 spare pre and 3 spare matched EL34 sets). Eliminated the wall socket as well & the power cable for the amp.

It's not over the top kinda hum, just low volume mild low frequency hum. It's not noticeable in a band setting but in my room standing in front of the amp 5 feet away I can hear it. Getting closer to the speaker it's a little buzzy sounding.

I have a feeling it maybe the building wiring, cause it reminds me of ground hum, but I was wondering if 50W or higher wattage amps are more prone to noise or if they generate some hum at idle on their own(enough to be heard when close mic'd).

Any thoughts?

 

[beaubrummels]

Re: Amp hum

I have Marshall, Orange, Hiwatt, Vox, Fender and the only one that is a known hum-monkey is the Vox, in fact it even warns you in the manual that when it's idle it will hum (part of the circuit design). The others I have don't hum like that at all with gains at 0 and master volumes down. Makes me wonder if you have an effects return or something that is after the master volume? I can't think of what would hum if the master is down.

 

[crusty philtrum]

Re: Amp hum

Any good amp tech will tell you that the reason an amp humms is because it doesn't know the words.

 

[Chris of Arabia]

Re: Amp hum

So long as it's humming in the right key, it shouldn't be a problem...

 

[Hank-]

Re: Amp hum

I have Marshall, Orange, Hiwatt, Vox, Fender and the only one that is a known hum-monkey is the Vox, in fact it even warns you in the manual that when it's idle it will hum (part of the circuit design). The others I have don't hum like that at all with gains at 0 and master volumes down. Makes me wonder if you have an effects return or something that is after the master volume? I can't think of what would hum if the master is down.

No the FX loop is before the volumes, the amp has independent volumes for each channel. Well, it seem my SS laney also has hum :/ That one is 6 yrs old, been in storage for a yr & half. I did go through each of them internally, didn't find any bad solder joints, caps also look healthy & tapping them didn't cause any pops/clicks either. So mostly building wiring I'm betting.

The only place I know that has clean power is the local music store. I'll drag the practice amp there & see how it behaves. If the hum goes away then all is good, if not then I'll change the filter caps in this one, they are 2200uF/25v so not a big deal. I happen to have spare ones lying around with exact same specs & same chinese brand, those were cheap to get too.

Funny thing is, looking at the insides of these amps, leaving aside the transformers& tube sockets;everything else I can replace for about total $150 max, cause most of them are chinese or malaysian components. If I'm able to fix it then cool or I'll send it in for repairs, see what exactly they do to fix it.
Most likely I won't need to bother doing anything, but getting the building's wiring fixed or cleaned up is, well, meh..

So long as it's humming in the right key, it shouldn't be a problem...

It's humming in the key of G#, well almost, not my favourite key though :nana:

 

[IM4Tone]

Re: Amp hum

Do all tube amps have some amount of hum emitting from the speakers without a guitar plugged into them?...................

Yes (at least all I've used). Why is that an issue?

 

[Hank-]

Re: Amp hum

^Not really an issue unless it's not supposed to behave that way. It's good to know that some hum is normal or some circuits have inherent hum, cause I've tried a roland cube(big one) & it was dead quite besides some faint white noise/hiss at louder volume.