Question about Onkyo TX-8511 Receiver

2 Answers

PROTECT Mode issue

My receiver works fine via its tuner section inputs (AM/FM). When in this mode I can crank up the output to at least 75% and only have trouble tollerating the pain in my ears. However, if I use a CD player, I can't crank the volume past 30% without having the TX-8511 go into PROTECT mode, which shuts down the output stage. I've tried several CD players and they all have the same results. I also tried a tape unit with a variable output and had similar problems as the tape units output level was increased. The PROTECT circuit threshold appears to activate when any combination of input signal level, output signal level and trebble/base level enhancements are met. Has anyone ever seen this before and can anyone help ?

Posted by Anonymous on

  • radio guy Nov 06, 2007

    my tx 8511 goes to protect mode about 20 seconds afer turning on. all volumes are set low.



2 Answers


Well let us start here ok one of my speakers blew the woofer blew out on my infinity speaker on the right side. Your amp will protect itself from being overloaded on one side of the power amp. This is what happened to me. So you should check your connections also this may also pose a problem. Make sure your speakers got 4 ohm or 8 ohm speakers switch dialed correctly on the rear of your power amp. check your ohm rating on your speakers also with a volt meter on your ohm setting which is very important which can damage your power amp if it is set wrong. You all have a great holliday season hope this helps.

Posted on Dec 15, 2007

  • Russ
    Russ Dec 28, 2014

    I had the same problem with my Onkyo TX-8511. I looked here for a solution and then investigated again. It seems that when the Onkyo volume is turned up somewhere past 5/8 of the way the protect mode kicks in. Solution was to turn up the individual speaker volumes and turn down the Onkyo main volume.




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Here you can get the owners manual for the unit if you need it; For the protect mode to kick in only for some input sources, then there would have to be a fault in one or more of the pre-amp circuits - there will be a separate one for the radio tuner. Probably the solution for such a good unit is to contact the manufacturers and see what they have to say - probably they will suggest you send it in for service and i suspect they would be right - here are the contact details if you happen to be in the US; or through this link if not; Hope this helps and you get an answer from them - it is probably fixable relatively easily and shouldn't be expensive for parts :)

Posted on Jun 23, 2007


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