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amp hum :( Faulty ac power?

twiiii said:
Sounds like your AC is using a two wire system with out the 3rd wire and you may have a bad connection to the neutrals. If the neutrals are Ok and you have copper water pipes you may want to ground the system to the water pipes or drive a 8 ft ground stake and connect a number 10 or 8 awg wire to the system. If you have very efficient speakers. you might need Mac Quad SS balanced amplifiers to gain an extra 20 db signal to noise.
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My house is the old two wire system. I did neaten up some of this years ago when remodeling and added a ground. It's been so long I don't remember what plugs had grounds! My new AC conditioner says line correct.
At this point I could be barking up the wrong tree. Basic trouble shooting would make me think. Two amps with similar problems,it must be something in the rest of the system. Disconnecting my source ruled out a lot. But still there is no rule that says that both amps couldn't just be broken. One amp is 40 years old. The other a near new,high quality unit but in my exp even nice things break.
I did somewhat recently change to high efficient speakers. I may hook up my old speakers and see if it's still audible from my seating position.
 
No, the HumDinger is NOT just a big capacitor. It uses a couple of big high voltage, high current diode bridges on each side of the AC power line, one each on the hot and neutral feeds. In addition there is a big 600V film capacitor (safety type) across the AC after the diode bridges. Finally there is a inrush current limiter on the incoming AC to help protect your equipment from line surges. The safety ground is a pass through from in to out.

The arrangement of the active parts are different from any other DC blocker and work very very well, especially for its very low price.

Frank
 
Are you hearing it thru' your speakers?
Is the transformer itself humming/buzzing?

You could be on a wild goose chase if you're confusing the two.
 
soulsurfing said:
Are you hearing it thru' your speakers?
Is the transformer itself humming/buzzing?

You could be on a wild goose chase if you're confusing the two.
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I should have been more specific. The hum is coming from the speakers. The hum increases and decreases with volume. The hum starts as soon as I hit the power button so that's before the tube section comes out of warm up mode.
 
I contacted mcintosh. They gave a fairly technical explanation of a ground loop. I removed the ground prong on a power cord(not the oem cord!). The result,near zero noise. Prob just normal noise floor. I will give it a few days and if the results stay the same I will see about a more permanent solution.
 
Donny said:
I contacted mcintosh. They gave a fairly technical explanation of a ground loop. I removed the ground prong on a power cord(not the oem cord!). The result,near zero noise. Prob just normal noise floor. I will give it a few days and if the results stay the same I will see about a more permanent solution.
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That makes sense and why I asked. Those AC line boxes that scrub DC from the mains, won't help in your case. They'll help keep the transformer from buzzing with DC, but will not stop other issues.
Trans hum won't be heard in the speakers at all.

Very glad you got this sorted. It can be a bugger to chase down hums/buzzes/hisses and such.
 
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