Problem with my amp

[SecretFace]

I have a problem with my amp and am wondering if anyone here can help. There seems to be something wrong with the power. When I use the distortion on the pedal and turn off the distortion on the amp, I get a strange effect. The all knobs on the guitar (volume, tone), and pedal (Tone, Level, Distrotion) are on ten and I am using the bridge pick ups. As I turn the volume up I get feedback and when feedback can't seem to get any louder as I continue to turn it up, the feedback oscelates and makes this pulsing noise. It almost sounds like I am using the tremolo pass on the amp. The power light on the amp fades in and out with the pulsing noise, which may be another clue. Worst of all, when I try to play, especially when I am chugging along on my E string (lowest), it takes a few notes for it to come in. Anyone have an idea of what's going on?


Amp: Fender Bullet 150
Power Requirements: 38W
Input Impedance: >1Mohm
Normal Input Level: 90Mw
Power Output: 15W R.M.S.
Rated Load Impedance: 8 Ohms
Speaker: 8" 8 Ohms

Pedal: Boss DS-1 Distortion
Normal Input Level -20 Dbu
Input Impedance: 470 Ohms
Normal Output Level: -20dBu
Output Impedance: 1 ohms
Current Draw: 4 mA (9 V DC)
Plugged into power strip with lots of other appliances

 

[jbwhite]

Re: Problem with my amp

i only get power to the wall outlet, what happend to it after it leaves the wall is someone elses job.

 

[tom baker]

Re: Problem with my amp

Try it at a different location, ie your neighbors.
If the problem follows the amp, its an amp problem.
If the problem stays, call an electrician.

 

[jimwalker]

Re: Problem with my amp

Plug a lamp into the outlet and while using the amp see if it stays bright or dims.

 

[SecretFace]

Re: Problem with my amp

There already is one plugged in! It doesn't flicker at all. I am starting to think it has something to do with magnetic fields or something. Anyone know about that stuff?

 

[charlie b]

Re: Problem with my amp

My guitar is acoustic (12 string Ovation). It has a built-in pickup, but none of the controls you described. So I do not know any of the terms you used to describe the problem.

Your odds of find a solution here are not very great. The membership is comprised mostly of people who work with electrical, and not electronic equipment. Still, there might be a member or two who share your musical talents, so stick around, and you might get lucky.

From the viewpoint of physics, however, I can make two comments.

First, the influence of magnetic fields is generally small, when you are dealing with household 60 cycle, 120 volt power systems. I doubt that any magnetic interference would be strong enough to cause an amplifier's "power available" of "power on" light to cycle on and off. I don't know what happens inside the amplifier, so I can't discount your suggestion. Still, I suspect the answer does not lie along that path.

Secondly, I recall from High School physics (don't ask how long ago that was, but I think McKinley was no longer president by then) that if you combine two sound signals that are sinusoidal, and that have very close frequencies, what you will hear is loudness followed by quiet followed by loudness followed by quiet. It is called "beat frequencies." If you measure the time interval between the periods of loudness, you can calculate the difference in frequencies between the two sound signals. I suspect that may be the source of the "pulsing noise" that you are describing.

 

[bphgravity]

Re: Problem with my amp

I doubt there is a problem with your electrical system from the outlet back. I would guess you either have a component problem or even a compatibility problem. I have a wiring system in my current home that was installed in 1957. Most of the branch circuit wiring has no EGC, the service is questionable, and many of the later year add-ons where done poorly.

Even so, I have not had any problems with my gear setup. The only time I do have problems is when a cable starts going bad or I arrange my "in and outs" of each pedal and component in a new configuration. I would check you equipment first.

It also sounds like you are overdriving the system. Turn some stuff down a bit.