Loud hum when powered on

If there is a router or you leave your phone near the speakers that is what is most likely causing the problem. Check to see if anything that gives off a wireless signal (eg. microwaves, cell phones, cordless phones) are nearby, and try to see if moving one of those things fixes your problem.

yes Best Buy sells powered subs sepratly

Yes, evaluate the load presented to its amplifiers by the speakers. If you have any speakers running parallel on the amps instead of one per amp channel you could be experiencing temporary unacceptable drops in impedance.

and

From page 57 in the manual...

• Turn down the volume.

• Lower the 40 Hz and 125 Hz equalizer levels in the Manual MCACC setup on page 34.

• Try switching on the digital safety feature (put the receiver into standby, hold down the SYSTEM SETUP button on the front panel and press STANDBY/ON to switch between SAFETY ON and SAFETY OFF

. If the power switches off even with SAFETY ON selected, turn down the volume.

A receiver with the specs...

* "90 watts minimum continuous power per channel, 8 ohm loads, 2 channels driven from 20 Hz to 20 kHz, with a maximum total harmonic distortion of 0.08%"

(*) The only acceptable statement of its power bandwidth in the manual.

... when fed an undistorted audio signal, used properly and not driven abto clipping is not particularly dangerous to any reputable speaker.

Driving any amplifier, even a modest one, into high distortion is more dangerous to any speaker than a high-powered amp pumping pure undistorted power.

Choose any speakers but low efficiency models if you want loud and clean sound.

jd40,
Sounds like a grounding issue. The first two places to look into is the powered subwoofer and antenna. During your last test, did you leave the FM antenna and subwoofer connected? Many times the hum is directly related to the antenna and/or the subwoofer and to how they are grounded; creating a ground loop through the receivers ground on the outlet. If the antenna is grounded to the dwellings wiring, hum is inevitable and sometime you can get a ground loop hum from how or how & where the subwoofer is grounded. Try taking them completely out of the loop.

Also try taking it further back to the basics, start with the receiver plugged into a known good grounded outlet with no surge or line conditioner in the loop and nothing connected to the receiver, nothing. Use one speaker and different wire to test each speaker output while in tuner and any other mode but phono. With no signal, you will either get nothing (no hum or static) or just static in the tuner mode. No hum is a good sign. Some systems will mute the speakers if no signal is connected to eliminate the static from being produced through the speakers but a ground loop hum will most likely still be produced even in mute. If you get a hum when nothing is connected to the receiver, try looking into getting a better grounded outlet, even maybe to a different dwelling.

-Chris

The hum (50 or 60 Hz) is caused by the AC power getting into the entry point of the amplifier. Either the filtering capacitors from the powersource of the speakers have dried up - replace them - or there is a short in the cables.
There is another possibility: if you have kicked the subwoofer  box its transformer might have slipped from its fixings and now is touching the subwoofer speaker frame.
The only way to find which is to open the cases.

Sounds like a power supply filter cap has gone bad.

The hum you're hearing could be the 60 Hz AC, especially if it is a low frequency.

If that IS what it is, the Zoom G2 was just a coincidence.

The hum you hear from the speakers and from the unit itself originate with 60hz AC power. They may not actually be related. Sometimes a transformer will hum slightly and unnoticeably. That you're getting a loud speaker hum says there is an electrical leak or a grounding issue somewhere.

Do all sources produce the hum or, say, just the phono? How about on headphones? Try rotating the AC plug. In those days they weren't keyed with one large blade as they are now.

There is a standby indication that activates after 10-15 minutes without any input signal. I suspect that might be what the red light is telling you - no signal.

Loud hum from a loosened cable is normal as hum usually means there's an ungrounded connection somewhere acting as an antenna and the amp is doing its job to amplify what it thinks is a signal, in this case 60hz stray ac current is being sensed nearby. It's a good sign that you get hum from the sub because that means the amp is alive.

Avoid manipulating cable connections with the Sub or Receiver turned on as you could introduce a static spike that could harm any connected equipment.

Are you certain a bass signal is making it into the sub? The complexities of modern AV receivers vary in how you configure them to direct LFE to a sub. Bone up on that end of the chain.

Or, just hang a CD player on the Inputs of the sub and play something with a reassonable amount of Low Frequencies.

>>>> Be advised that this way of testing has NO VOLUME CONTROL because amps without volume controls always operate at maximum gain, relying on your external controls to attentuate it (hence, the loud hum from a loose cable); so choose a track that eases into the loud parts with some quiet parts up front and BE READY TO PAUSE THE PROGRAM AT ANY SIGNS OF STRESS. <<<<

A living sub will produce only muffled rumble in the absence of other speakers producing the higher frequencies which carry the intelligence of the signal. If that works, back to the receiver for settings. If not... sigh.

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For hum problems, even those you cause yourself:

Disconnect all inputs to see if that helps. If it goes away start with the signal cables and add in things until it comes back.

Sometimes the reversing the orientation of the AC plug can help with hum. Or it could be something like a loose or high resistance connection internal to the sub. Good luck.