Axiom Home Page Forums General Discussion Home Theater Onkyo 875

Thanks Peter. Looks like I need a new hifi rack!

I believe 3.1 was refering to the surround channels and center plus sub in a 5.1 system. not 3.1 as in front 3 plus sub. I should think if it cuts out running 2 surrounds and the center then it must be getting very hot.

Drew, as you describe the situation, the problem is almost certainly overheating alone. You didn't describe exactly how you measured the 100dB level, but assuming that your number is reasonably accurate for the max level, your M80s were using only around 20 watts for that peak. The 875 has been measured to be capable of more than 200 watts in such a situation. The protective circuits wouldn't have shut down because of excessive power/current being used.

As others have suggested, more ventilation room and/or a cooling fan would be advisable.

No problem drewy1!

Was the 875 in the 4-ohm or 6+ ohm mode when it shut down?

Here's a simple test....

If you can, pull the 875 out of the AV rack so that it's not confined. See if you can then get it to shut down at the volume levels that you wish to drive. Don't overdo it, but get it back to the volume level you want.

If it doesn't shut down, then it was the confined space. Get a new AV rack or explore the many DIY fan options that Onkyo users have come up with over on AVS.

If it does still shut down, then it isn't due to the confined space. If that's the case, then you may need to either get a different AVR or go whole-hog and buy an amp.

And another tip...

I know that with the 876 there was actually a "secret" set of key presses (on the front panel) that would display the AVR's internal temperature. A lot of people with heat issues would use this to see how close they were to having thermal problems. And to monitor how their DIY fan solutions were working. I don't know what it was, but if you peruse the AVS forums you might find something similar on the 875. Since they're so closely related, I'd be surprised if the 875 lacked this feature.

One thing I noticed in studying receivers lately, is how much heavier the Onkyo's are compared to Denon. They must have beefier guts or something, which can't be a bad thing.

The 876 (51 lbs) and 906 (59 lbs) compared to the Denon 3808 (39 lbs) and 4808 (41.6 lbs) has be thinking if I get a new receiver to give Onkyo a shot. That is a lot of difference.

Or Onkyo is gluing lead weights inside.

Beefier guts or thicker skin? Denon runs 4ohm loads(loudly) no issues, Onkyo appears to overheat, something seems wrong with the equation.

Awww, can't they use gold?

The new Onkyo's have issues? Now looking at the ventilation requirements, I wonder if that could be related. Being THX+ rated they should be fine with 4ohm loads, like the 80's.

Well the 875/876s, we are seeing reports of some shutting down, albeit at extreme levels, but still shutting down.

It does appear that the Onkyo's are shutting down due to heat issues from driving the lower loads and that better ventilation is required, maybe they need to be 70lbs, this would be with better heat sinks and some fans But for your purposes Randy, you have those Odyssey's so a major part of the load would be taken off the amps anyway.