Diagnosis with Stereo Amp Problem (random hissing and pop and power spikes?)

[tikitariki]

Hope this is the right forum for this question.

I am very new to home studio recording. I got a new job a few months ago and picked up some monitors and an amp. They work and sound great. The amp is 300w and occasionally will produce a hiss, regardless of the volume, channel, or really any option. And sometimes a crackle and a pop. It is really irritating just hanging around my computer. When sound plays, it doesn't seem to happen as often, but it messes up music, of course.

I ruled out that it is not the speakers because I would figure the volume would effect the pop sound and stuff. I am plugged into a power surger. This is really the limitation of my knowledge. I don't know if it could be dust (is that a real possibility?), the electricity in my house being poor, or if the amp needs internal parts replace.

Also, some additional non-issue related questions:

300w amp. I have two different speakers set up for 'Speaker B' and it says 4 ohms vs. using both Speaker A and B for 8 ohms. I have two little displays for watts, both go up to 150. Since it's on one speaker (channel?) for both, only one display moves. The peak level is 150 I'm guessing as that is as far as it goes. Is it bad for the amp to hit 300w of power? If I'm using two speakers on one channel, is my real limit increased from 150 to 300, so I can technically turn bass and treble up when not recording/mixing? Any kind of simple literature on this would be appreciated.

SEE ATTACHMENT FOR IMAGE

 

[mjbphotos]

If the amp makes random noises (I assume produced through the speaker, not from the amp itself), then either you've got some bad wires/cables, or there are components in the amp that are on their way out.

If the amp is 300 watts stereo (4 ohms) and you only have one 4 ohm speaker hooked up to one channel, then you are only going to get 150 watts. If you've got two 4-ohm speakers hooked up in series for a an 8 ohm load, you're not going to get 150 watts (most likely 75 watts). IF you've the two 4-ohm speakers hooked up in parallel, then that's a 2 ohm load and you could overdrive the amp to 300 watts on that channel.

 

[Bobbsy]

From your description, I'd place a fairly small bet on it being electrolytic capacitors in the amp (possibly the power supply section) drying out--something they always do with age.

 

[tikitariki]

Thank you for the replies. Another way to help diagnose is that if I turn on a light or turn off a light in the house, it'll stop the growing hiss sometimes.

Also, I'm not sure how to find out the ohms of my speakers. I'm guessing the guy set it up like this for the whole overdrive thing. But I am just wondering the limitations of it. I don't put the speakers too loud, but sometimes I want to for non-music production related things, such as movies or games and when I see the little dash show the peak usage fly up to 150 I get nervous, purely out of just not knowing if that is even okay or not.

 

[Farview]

With a 300 watt stereo amp, that normally means 150 watts per channel. If that is peak power, then the amp is really probably only capable of putting out about half of that in average signal level.

Hooking more than one speaker up to a single channel is normally a bad idea, unless there is a button on the amp that allows you to run speakers B at the same time as speakers A.

 

[tikitariki]

still haven't resolved this and it is driving me crazy as it makes my guitar sound terrible. Another thing that can help diagnose it:

when a light switch is turned on or off randomly throughout the house, it will fix the problem temporarily.

Switching from CD/AUX to PHONO or something else also temporarily fixes the problem.

I really just want an easy fix for this. Is it the electricity in my house? It is ruining my production cause sometimes it will come on and slightly distort the music ever so slightly, maybe with slightly more bass.