.....well, I suppose it's a Combo really.....maybe.....anyway, who cares? It's one of these:
http://www.marshallamps.com/product.asp?productCode=MG15CDR
I've had it a few weeks now and I can't seem to get it to be 'quiet'. I don't mean that I can't get it to play quietly, because it will, what I mean is that I get an almost constant hissing sound with and without a guitar plugged into it.
If I plug a guitar in and turn on the Overdrive channel I get a slightly different problem - I get a sort of buzzing combined with the hissing, this time the buzzing gets less noticeable if I touch the bridge/strings on the guitar but unplugging the guitar doesn't have any effect.
I'm guessing that I've got a grounding problem somewhere, but is it a problem with the amp or a problem with the wiring in the house? Is this something I can fix myself or am I doomed to never be able to get a nice clean sound?
I love the amp by the way, it sounds great when it's cranked - I'd just like it to sound nice and quiet even when I'm not making a racket on purpose :)
Cheers guys.
Rumour has it that if you play Microsoft CDs backwards you will hear Satanic messages.
Worse still, is that if you play them forwards they will install Windows.
Are you in a room with flouresent lights or a computer or tv? all of these will cause hum. Alternatively it could be an outlet grounding issue to test an outlet for grounding read This
Personally I use an AC outlet curcuit tester it looks like this 
You can find them at hardware stores for around $10. If your not grounded I'm not sure how to fix the problem short of rewiring your house :oops:
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I've got a Marshall MG30DFX, and never noticed a hiss or a hum in in it, but the wiring in my house is all up to standard as of 2000. None of the potential noise sources nearby like A&L mentioned, either.
Some amps do have a perpetual hiss, like the Danelectro "Nifty Fifty." There's one of those in this household, too, but I haven't gotten around to putting a "high-cut" filter on it yet. (Info found in a review of that model on another site.) Your Marshall might need something like that added, although a filter can also change your tone somewhat.
Besides checking the house wiring, I'd suggest running the tests found here: http://www.guitarnuts.com/technical/electrical/trouble/index.php . That'll help root out noise sources in other parts of your setup.
One test is to touch the strings with your fingers. If the hum goes away, then it's a grounding problem.
Another possibility is that your guitar might not be sheilded properly, especially if it's a single coil.
This problem is much worse when you have a TV, computeror flourescent lights.
Here's an awesome site
http://www.guitarnuts.com/wiring/shielding/shield3.php
1 watt of pure tube tone - the Living Room Amp!
http://www.naturdoctor.com/Chapters/Amps/LivingRoomAmp.html
Paper-in-oil caps rule!
Does the amp have a polarity switch to change the polarity? Is the amp grounded?
Joe
