Continually tripping protection circuit(s) at volume

[Emjay]

First up, apologies, this is going to be a long post!

 

I have a friend (no, really, this isn't me too embarrassed to admit it!) who has recently stepped up from a Logitech 5.1 speaker setup to Klipsch (on my recommendation)

 

He purchased 4x RB-41s and an RC-52 from ebay, and was using the 5-channel stereo mode when listening to music.

 

I gave him an old Marantz slim-line receiver which only output 50 watts into 8ohm, which he was continually sending into protection mode once the volume was around 0dB (max volume being +18).

 

Growing frustrated with the continual protection mode, he purchased a brand new Denon X4000 AVR (rated at 125>>8) which also goes into protection mode

 

I told him that, in my experience, protection mode is often caused due to a short somewhere. We both checked/double-checked that there were no shorts at either end; some of his speaker wire had, over the years, been roughed up, so he ended up replacing all wiring with brand new 13guage wire.

 

Still tripping protection.

 

I don't believe it's thermal, because I checked the Denon support site, and it stated that, if the AVR shuts down due to over-heating, the amp will cut out until the temperature drops, then come back on. This never happened, even leaving it for 30 minutes.

 

I've told him that little book-shelf speakers cannot and will not fill the entire neighbourhood with sound; his position is that he should be able to run the amp around 0dB for extended periods without issue.

 

He read an article claiming that bookshelf speakers + sub can be as effective as floor-standers, so wouldn't listen to this argument.

 

I convinced him to try just 2-channel stereo mode, rather than the 5-channel mode, but this made no real difference.

 

I also lent him a pair of RB-61s which I wasn't using, which seems to have won him over to my 'bigger is better' philosophy - he currently has a pair of RF-52s in transit.

 

In the mean-time, I came across a number of forum posts wherein the point was repeatedly made that you cannot run an AVR at or above 0dB for any length of time; when I pointed this out to him, he decided to buy a dedicated power amp for the front 2.

 

Fast-forward to today, and he purchased a NAD C372 from ebay (one that I'd had my eye on, as well!) and, while acknowledging that he is getting more volume than before, he remains displeased, because now the NAD is tripping it's protection circuit when he cranks the volume.

 

I'm fresh out of ideas for him (other than the 1 I keep returning to - that he can't expect to fill the entire suburb with concert-level sound!). He's now upgraded from PS3 to Cambridge Audio 650BD for CD play-back, replaced all the HDMI/RCA leads, speaker wire, speakers (he's still using my RB-61s until his RF-52s arrive), AVR and is using a dedicated power amp (pre-outs from the Denon), and still tripping protection mode.

 

He is convinced that he should be able to run the amp(s) at volume "without worrying about it cutting out".

 

He's considering buying some sort of power conditioner to see if it's a power issue from the mains; I told him I'd post here to see if anyone has any other ideas.

 

So, thanks if you've made it all the way through this - do you have any other suggestions?

[geoffcb]

Maybe it's his circuit breaker - has he checked this? Why does he want it so loud - or is this a silly question?

 

Geoff

[Taz]

He might use a 12 gauge power cord to a different circuit to check if the breaker he is presently using is bad.  If it continues to trip breaker on different circuits it is not a breaker  problem.

[Emjay]

Why does he want it so loud - or is this a silly question?

 

Geoff

Because he can

 

(except he can't!)

 

He wants to be able to listen to the music from outside.

 

I tried telling him to get some out-door speakers on zone-2, in this case, but...

 

[derrickdj1]

The small speaker are lower sensitivity and he does not have enough amp power.  Also check for stray wires.

[Emjay]

The small speaker are lower sensitivity and he does not have enough amp power.  Also check for stray wires.

I'm pretty sure we can rule out wiring, now

 

Do you really think the answer is more power?

[Taz]

Sounds comparable to trying to race your Geo Metro on the Freeway.  It just ain't going to work.  He don't need more power as much as he needs more efficient speakers..  Or he could put those speakers outside weather permitting.  But I suspect he still will not be satisfied.

[willland]

The small speaker are lower sensitivity and he does not have enough amp power.

 

That NAD C372 should have no problem driving his speakers to whatever level he chooses, unless something is wrong with it also.

 

Bill

Also check for stray wires.

 

Of course that could be the problem.

 

Do you really think the answer is more power?

 

Not if he is using the NAD.

 

Bill 

[willland]

He read an article claiming that bookshelf speakers + sub can be as effective as floor-standers, so wouldn't listen to this argument.

 

Yeah if he is using RB-75's, but only maybe with his RB-41II's unless it is in an 8'L x 9"W x 8"H room.  

 

Bill 

[ricktate]

I assume it is the amps shutting down not the circuit breaker in the fuse box? So that being said I bought my son some rb-35s and I hooked them up in front of k-horns with 24 watts they got almost as loud as the Ks so I do not think power is the problem.

  So you did not say how big room was or what size of wire he is using. So suspect he has bass turned up and those little speakers can not handle it my first thoughts are the wire or the wiring but you say that's ok. Then he needs a sub woofer to take the load off the amps. I can tell you 24 watt 1974 receiver hooked to RB 35s can run you out of the house but not make the deep movie bass he probably wants.

   You did not say how much power he had going to speakers but most AVRs only put out 80 watts in 5 channel mode. But even that should be loud enough I would think.

    Try a sub see what happens.   Rick

[Emjay]

I thought I'd included everything above, but forgot to mention - he's running a sub (Klipsch SW10), with the Audyssey-set xover @ 60Hz

 

Previously, when using the RB-41s, Audyssey set the xover @ 80Hz

 

I did mention:

X4000 is rated @ 125wpc (2-channel driven)

All speaker wire has now been replaced with 13 gauge wire

 

Also, for completeness, the NAD is rated to 150wpc and, according to the stereophile measurements, delivers this easily (http://www.stereophile.com/content/nad-c-372-integrated-amplifier-specifications)

[Don Richard]

Not enough rig for the gig. If he wants to damage his hearing as rapidly as possible it will require speakers that can deliver 125+ dB SPL and the amplification to drive them to that level. Perhaps he already has hearing damage?

[JJkizak]

Is 13 gauge wire something new?

JJK

[mark1101]

The NAD C372 can be bridged for 300 wpc/8 ohms.  Download the manual and read how to do it.  Pretty simple.

 

If that doesn't do it for him I don't know what will.

 

Also, I did a quick search and ran into several reviews.  Apparently, there are a lot of negative reviews about this unit and its reliability and sound quality.

[Thaddeus Smith]

 

The small speaker are lower sensitivity and he does not have enough amp power.  Also check for stray wires.

I'm pretty sure we can rule out wiring, now

 

Do you really think the answer is more power?

 

 

I have a hard time accepting that Denon's top mid-tier receiver, rated at 125wpc, can't drive these bookshelf speakers to ear bleeding levels. Do you guys even check model specs before making statements?

[Thaddeus Smith]

The NAD C372 can be bridged for 300 wpc/8 ohms.  Download the manual and read how to do it.  Pretty simple.

 

If that doesn't do it for him I don't know what will.

 

Also, I did a quick search and ran into several reviews.  Apparently, there are a lot of negative reviews about this unit and its reliability and sound quality.

 

can you link to some? I spent a considerable amount of time researching the X-4000 and never came across negative reviews.

 

edit: re-reading context and I think you were talking entirely about the NAD.

Edited October 20, 2014 by Thaddeus Smith

[Marvel]

There isn't a change the polarity is reversed on one channel is there?

 

Bruce

[CECAA850]

Can't believe no one has suggested this.

 

Disconnect all speaker wires from the receiver.  Start out with one speaker and crank it up.  One of 2 things will happen.  It will play fine or go into protection.

 

If it plays fine, keep adding speakers one at a time and cranking it up till you add the speaker that's making it go into protection mode.  Carefully examine the wire.  If no issues, the short or problem is in the speaker.

 

If the receiver goes into protection with the first one hooked up, it may be the bad one, try another.

 

I've had wires touch on the spider of the woofer ONLY at high volumes and driver excursion, all you have to do is move the wires at the spider.

[Emjay]

The real issue at hand is - should you be able to run an AVR or power amplifier > 75% for extended periods of time while listening to music

 

I'm not a fan of the sort of music he likes - he tends to like punk and metal and other music where there's a constant wall of sound, Personally I like music that has quieter moments leading to a crescendo 

 

I am able to watch the Eagles Farewell I blu ray with my Marantz AVR at 0 for 2 1/2 hours without issue, but this has more peaks and troughs than his preferred music, so probably doesn't require the same sort of constant power output

 

On another front - 

 

RB-61 is rated at 95dB/1 watt/1 metre

 

RF-52 is actually the same

 

Both have power handling of 100w continuous

 

Am I right, then, in my understanding that it works like:

 

Watts SPL

1         95

2         98

4        101

8        104

16      107

32      110

64      113

128    116

 

And that the apparent volume drops by 6dB with each doubling of distance?

 

Distance Apparent SPL

1              116

2              110

4              104

8               98

Edited October 20, 2014 by Emjay

[Emjay]

Can't believe no one has suggested this.

 

Disconnect all speaker wires from the receiver.  Start out with one speaker and crank it up.  One of 2 things will happen.  It will play fine or go into protection.

 

This issue has been apparent across 3 different pairs of speakers in stereo mode (2x pair of RB-41s and 1x pair of RB-61s)

 

Speaker wire has been fully replaced

 

1 x Marantz slim-line AVR, 1 x Denon AVR, 1 x NAD dedicated power amp all trip protection

 

Initially, he was using PS3 as CD player. We read some forums that the PS3 outputs 5.1 via HDMI at all times (3.1 of silence when playing CD) so, thinking this might be putting unnecessary load on the AVR, he purchased a used Cambridge Audio 650BD.

 

HDMI lead has been replaced

 

None of this has resolved the issue