Help - funny guitar amp issue, any advice greatly appreciated


Dec 19, 2003
Hi all,

Am currently setting up a (pc based) home studio for recording own band(s). Everything's been going fine, have recorded an album worth of drum tracks and have just started on the guitars.

Amp is 5150 close mic'd sm57. Have noticed a 'phasing' sound, so started investigating all the ususals. However, have noticed it's ANY amp i use.

To best describe it, if you played open, distorted, chords it'd sound like a wah been slightly depressed every second or so, a kind of pumping / phasing sound. I've tried a 5150, triple xxx, marshall, even a tranny amp, all do the same! I've also tried different rooms to no avail. Before now, i've not played amps at home, always in rehersal rooms.

My suspicion is it's the power. I live in an old victorian terrace, could it be 'dodgy' power? Would this lead to this sort of effect? If so, what can I do to rectify it?

Going to takes amps round a friends house and have a carefull listen to see if this could be something i'm missing.

Any other suggestions would be greatly appreciated!!!!

many thanks,

Hi Andy, thanks for replying.

57 is about an inch off centre & about inch back from cloth.

However, i get the same issue without any mic-ing. I only really noticed it when i started recording, it's a lot more pronounced. Just listening to the amp in the room, you can still hear the issue, it's just you probably wouldn't notice it when practising / playing. As soon as it's (any amp) is mic'd you can see the level fluctuating up and down on the meters and hear the problem a lot more.....
hmm, good question, i shall try a few more things out tonight and post my findings later, i'll try a few speakers / guitar / pickup / lead combinations....
I know this may be stupid, but are you in tune? I can't tell you how many people complain to me about their "thin" or "warbly" guitar tone on their demo who give the tracks to me to fix, and they're all just out of tune. But assuming that you're in tune, Andy is probably right about it either being a bad speaker, bad wiring, or some impedance problem.
yeah, take the point about the tuning, know what you mean, however guitars tuned with tuner (as opposed to by ear)

ok, more info....

i've tried a 5150 2x12 combo, triple xxx head and marshall head with 3 different cabs, and an old peavey bandit I had knocking around. Also tried a variety of leads and 3 different guitars in 3 different tunings, the problem happens with everything (amps alone, not even mic-ing when testing now)!!!

all i can think now is the power supply is causing this....
Have tried different sockets / different rooms, no joy. Even had a mate come and listen as I thought I might just be going a tad mad! But nope, problem still there. Going to lug all my gear over to his place over the weekend to see if it's ok there / try and get to the bottom of what's going on!!!