Originally Posted by woots
Is this the problem people report when they say hum? I know a few people did that dead signal max volume test... but I assumed they were hearing a hum when they listen to normal audio playback (without doing wacky tests). Lol.. why would anyone switch to no input and turn up volume to max and complain when they hear weird things? ... thats a simple fix.. just don't do that!
I posted this in another thread
dedicated to the "Hum" issue but it hasn't seen much action so I thought I'd give it a try here.
I found I had the "Sub Hum" by pure accident. I was listening to some music through my new Panasonic DMP-BD30K and decided to turn off the TV (Sharp LC-52D64U) to see what would happen when I broke the HDMI chain. Well it caused the CD to stop playing and I heard the hum.
Here's what I have in my setup...
Comcast Motorola DCH-3416 DVR connected to the 705 via HDMI ony (connected to the CBL/SAT input)
Panasonic DMP-BD30K Blu-Ray connected to the 705 via HDMI ony (connected to the DVD input)
Toshiba HD-A2 HD-DVD connected to the 705 via HDMI ony (connected to the AUX input)
Onkyo TX-SR705 connected to the Sharp LC-52D64U via HDMI and Toslink Optical from the Sharp LC-52D64U to the Onkyo TX-SR705 (OPT1 configured to VCR/DVR) to send sound out when using the TV tuner which is connected to Comcast cable directly from the wall.
Infinity "Primus" 360 mains, Infinity "Primus" 250 surrounds, Infinity "Primus" C25 center and two (2) Infinity PS-8 subs.
I have since done some testing and found I have zero hum when the Onkyo TX-SR705 is on and the other components are off except the VCR/DVR input when the Sharp is off there is still a hum.
705 on DVD input, Panny BD30 off, Sharp off > no hum
705 on CBL/SAT input, Cable Box off, Sharp off > no hum
705 on AUX input, Toshiba HD-A2 off, Sharp off > no hum
705 on VCR/DVR input, Sharp off, > hum
all other inputs, there seems to be no hum and the hum is only noticeable at 3/4 volume or higher and not during normal viewing or listening.
This is the only testing I've done so far and took all of about 15 minutes. I'm going to give Onkyo a call on Monday and see what they have to say. I'm outside my 30 day return window so that's not an option.
I'll be sure to post back if I find out anything...
*UPDATE* I did a little more testing and found something odd. I played a movie in the Blu-Ray player, stopped the player, removed movie from tray, closed tray, NO HUM @ max volume. I then switched inputs (pressed CBL/SAT on the 705) and immediately back to the DVD input and immediately had the "Sub Hum" again. This is a real head scratcher...