QuestionQUESTION: the following text is from a conversations with the manufacture of this amp
how do i identify ground loop hum ?
dose the hum come and go or slowly pulsate ?
and where do you hear it from ? (speakers/amp)
i have a slow hum that comes and goes (1-3 times a minute)(creeps in and out) and it comes from the amp not the speakers ...... is this ground loop hum ?
What you are describing sounds like mechanical hum from the transformer which is usually caused by something external to the amp, it's rare to have a faulty transformer. It's something we never see with these amps.
Use a heavy extension cord to plug the amp into several different circuits throughout your home. You should eventually come across an outlet where it no longer hums. If the problem ceases to exist with another outlet then there is most likely too much current draw. A textbook symptom of inadequate power with an amp using a toriodal transformer is that it will hum from the chassis if there is a voltage sag. Sometimes it's not the voltage, it's DC offset voltage across the AC line. Unfortunately this is tough to pinpoint, the only way to verify whether it's the amp or environment is to physically move the amp to another location. Obviously this is the last course of troubleshooting but it's sometimes necessary. It's probably nothing to worry about and you should be able to pinpoint the problem using the extension cord tecnique. It could be something as simple as a halogen lamp on the same circuit. During troubleshooting try to think of anything sharing an outlet in that room however benign you may think it is, dimmer switches, heater, any appliance, etc. I should add that we've had a few amps sent in for mechanical hum and to the best of my knowledge none have exhibited hum in our test environment. Please be syre to contact me if you have any questions or need to troubleshoot further.
HELLO STEVE:
After using the above extension cord tecnique i found the hum went away.
So i added a seperate 20 amp circuit just for the amp .... it worked but only if thats
all that was connected into that Plug as soon as i add ANYTHING Else (EX:Pre/Pro) the Hum would return
so i just run the AMP without sharing the outlet .... so far so good
Now just the other day while listening to music (not that it matters but low volume) and working around the house my wife turns on the hair dryer in the bath room and slowly the sound disappears
and the HUM returns (turning the hair dryer off everything returns to noraml)
Is that AMP drawing that much current that i can't run it in MY HOUSE ??? (I really don't want to return it) but i'am a little confused about what i should do and what my options are
ANSWER: whew!!! it sorta sounds like your home wiring could still be the culprit, how old is the wiring in the house, are all outlets 3 wire type? it's also possible that the feed coming into your house has corroded after time, making connections less than ideal. the power company is responsible from source to your service meter, i'd call them with your coincidences with hair drier and other high current devices are on, possibly a sign of poor connections. good luck, you have a tough nut to crack on this one. if you have a generator, you could just try using it to show if it is a power co. issue...
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QUESTION: Thank You for such a QUICK response to my question
I understand you really can't do much for me via Email but with the info i've given would you say that the amp is NOT the Problem ?
Answeryou have to disprove other things first, after you've eliminated everything else, then you can say it's the amp. it would suck to get another amp and see the same problem arise again. take it to a friends' house and hook it up just to see if it's fine there.
