It takes mor power to drive lower frequencies. This is why the bass should be turned down and the crossover set higher. I used to use a Carver av-705x 5-channel x 125 watt amp. I have recently bought two 755 amps. Let me tell you there is a world of difference between a 125 watt and 200 watt per channel amp. A 125 watt amp may give a slight edge over a receiver's internal amp section, but the 200 watt amp has more head room and better dynamics. A good part of this is due to bigger transformers and caps inside the amp. You can never have enough power. I drive Klipsch speakers and probably use a small fraction of the 755's power, but the jump to the 200 watt amp has made a huge difference, especially in the lower frequencies. I use one of the amps to drive the surround channels and a pair of SVS 20-39CS+ subs and have never heard the 200 watt model strain whatsoever.

Doug917,

I am aware that directing bass to the sub lightens the load for the receiver/amp... but DDavid said the following:

"Has anyone experience the 7125 shutting down the front left and right channels after about 15 minutes of playing at high volume? I am using Klipsch RF35 as mains . They are 8 ohms. "

My Rocket mains and surrounds are 6 ohm, with a 4 ohm center. I drive them with an Onkyo TX-SR702 rated at 100 W/ch, but will 5 channels driven it's probably closer to 50 W/ch. And the Onkyo drove them for 6 months before I got the SVS, so all 5 speakers were set Large.

During those 6 months, I listened to movies at 72 dB at the listening position 13 feet from the mains/center... so the mains/center were putting out 84 dB at 1 meter (plus more dB for peaks)

DDavid did not mention the dB level at his listening position, but if my Onkyo 702 drove the 4 ohm center (receiver is rated at 6 ohm and above), and 6 ohm mains and 2 surrounds, all full-range without ever shutting down, then it's no wonder why I am concerned with the shut-down issue.

-T

Since I've never experienced this before with my amp, I have to ask this question: would overheating or overdriving of an amp ever shut down just specific channels? I was always under the impression that the power supply is what cuts out under duress. Am I underinformed here?

T-Bone,

I would agree the amp should power the speakers to insane (Klipsch have very high sensitivity) levels before shutting down. We need more info as far bass settings, tone control settings, SPL measurement he's listening at, etc.

DDavid,

Have you rechecked all the speaker wire connections to make sure there were no stray wires making contact anywhere?

Sluggo,

I'm under the impression he was just listening to 2-channel stereo and it shut down the amp. I could be mistaken here. However, depending on how modular an amp is, I could see one shutting down individual channels.

There is no shutdown issue. We have hundreds of these amplifiers in the field that have had absolutely no issue driving difficult loads. While one gentleman (DDavid) had an issue, it is unclear what specifically caused the shutdown in his system.

Bass and treble are set to 0 on the 990. I used the auto setup and front speakers are at 17 feet. Speakers are set to small- 80hz. Volume on the 990 is between -6 to 0. I was listening to 2-channel stereo. Customer service are extremely helpful. They sent me a new 7125 and after about 45 mins it shut down the left front channel. Maybe it something else. I'll troubleshoot some more and update all. Any suggestions will be greatly appreciated. Thanks everyone.

i would start looking at the speakers.i'm sure you know,next move is to switch front speakers,and see what happens.

also,what is the mic. location relative to l & r speakers,you stated auto-setup,equal distance to both?

re-reading this post has me thinking,it's maybe a bass issue with your speakers,maybe a driver,maybe an inductor in the x-over(speaker's)

some thing gets hot,it fails,amps protection circuit protects amp.
seems like you changed the bass to your klipsch and it took longer to get hot and fail??maybe??

i had a similar problem years ago.

will it come back on immediately?(after shutting amp off)will it shut down immediately?

give some more description of exactly what's happenning.

Sluggo:

I have managed to shut my 7100 down only one time in about 2 years. I was driving it hard for over an hour and a half and it sits in a rather small space(only 3 1/2" above and glass doors in front so not a lot of air flow. It only made the right front channel stop so I would say that each channel has its own shut off. After I let it cool down it has performed flawlessly. Hope this helps

Lasher

Okay, after seeing DDavid's last response, and Scott's too, I'll agree that there is no shutdown issue.

Good to know... I would have hated to scratch the 7125 off my shortlist.

-T