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Peavy Clip Light - Page 2

post #31 of 40
I'm running both of mine on 20 amp circuits. I've only had mine trip the breaker once and it was me getting pretty stupid with the volume. Most of the time my wife will 'trip' before the breakers will. biggrin.gif I have never seen the clip lights though as I'm far outpowering the drivers with my setup - 4 RSS18 drivers on each amp. The amp is very efficient, but it's also very powerful and will draw strong bursts of power. I'm surprised yours is tripping though, maybe your breaker is more sensitive? In any event upgrading to a 30amp line isn't a terrible idea and is probably required to draw full power of the amp.
post #32 of 40
Quote:
Originally Posted by pdxrealtor View Post

Complete gut and remodel added a lot of stuff to the panel. We have several tandem breakers. Not sure on the number.

Ill have to look when I get back to town.

I gotta figure out why a dedicated 20 amp is triping on ~5500 wats. Im not even using the full 7500 of the peavy......

Have you double or triple checked all the speaker and amp connections and settings?

While it's not super common, it's not unheard of to have a weak breaker.

That said, it still comes down to duty cycle. Based on how you have the amp loaded and using Peavey power draw specs, the amp should be pulling about 10A average if the clipping indicators occasionally flash (~1/8 power, average). However, if they're flashing pretty often it could be up around 22A (~1/3 power, average). If, as mentioned in one post, the clip indicator(s) flashing most of the time or are on solid, it's pulling considerably more than that.

Sorta what you're doing playing tones or long bass tracks to the point of having the clip indicators lit up is like bench testing the amp at high power. A 20A line won't allow this amp to deliver continuous rated power for very long at all.

If the amp is in the red more often than not it may simply be you don't have enough rig for the gig, or that something isn't set up right.
Edited by whoaru99 - 10/29/13 at 5:42am
post #33 of 40
Thread Starter 
Quote:
Originally Posted by Gorilla83 View Post

I'm running both of mine on 20 amp circuits. I've only had mine trip the breaker once and it was me getting pretty stupid with the volume. Most of the time my wife will 'trip' before the breakers will. biggrin.gif I have never seen the clip lights though as I'm far outpowering the drivers with my setup - 4 RSS18 drivers on each amp. The amp is very efficient, but it's also very powerful and will draw strong bursts of power. I'm surprised yours is tripping though, maybe your breaker is more sensitive? In any event upgrading to a 30amp line isn't a terrible idea and is probably required to draw full power of the amp.

Quote:
Originally Posted by whoaru99 View Post

Have you double or triple checked all the speaker and amp connections and settings?

While it's not super common, it's not unheard of to have a weak breaker.

That said, it still comes down to duty cycle. Based on how you have the amp loaded and using Peavey power draw specs, the amp should be pulling about 10A average if the clipping indicators occasionally flash (~1/8 power, average). However, if they're flashing pretty often it could be up around 22A (~1/3 power, average). If, as mentioned in one post, the clip indicator(s) flashing most of the time or are on solid, it's pulling considerably more than that.

Sorta what you're doing playing tones or long bass tracks to the point of having the clip indicators lit up is like bench testing the amp at high power. A 20A line won't allow this amp to deliver continuous rated power for very long at all.

If the amp is in the red more often than not it may simply be you don't have enough rig for the gig, or that something isn't set up right.

I checked each cabinet for the correct ohm load, and then each channel for correct ohm load.

The clip (ddt) lights have not come on since I set the gain structure using the home theater shacks guide. The breaker trips first.

Not even tickling the light on the REW sweeps.

Ill have to post the sub demo music Im using and have someone else test their setup if they dont mind. The first song is basically a sweep, but later on petey pablo's freak o leak has some nice bass, and it trips my breaker too.

I can also swap out breakers.

Last resort is running a 30 amp. Im hoping if I have to dot that the line is straight enough to pull without removing sheetrock...... Again.
post #34 of 40
Quote:
Originally Posted by Wayne A. Pflughaupt View Post

The clip lights only show that the amplifier’s inputs are being overdriven. ]

I thought it was the outputs being overdriven, i.e. when the PS rail voltage is exceeded.
post #35 of 40
I seem to recall reading some past discussions here on AVS where it was said that in some cases clipping indicators are/were based on input signal levels. Not that the clip lights indicate overload of the inputs, but that they correlate to the output because the gain of the amp is known.
post #36 of 40
Quote:
Originally Posted by noah katz View Post

I thought it was the outputs being overdriven, i.e. when the PS rail voltage is exceeded.


Nope – the clip lights only show that the input signal is too high. For instance, unplug the load (speaker) from the amp and what happens to the clip indicators? Nothing – they will keep right on lighting.

Not that the clip indicators are meaningless: If the amp’s inputs are clipping, then a square-wave signal is being sent to the amplifier section, and you’ll get audible distortion. However, the amp will keep going, with the clip indicators lit up like a Christmas tree, right up to the point where it fries the speaker – i.e., melts the voice coil. Why didn’t the amp shut down first? Because it wasn’t overloaded. That is, the current demand (determined by the impedance load) never exceeded the power supply’s capabilities. (Typically you won’t fry a speaker whose impedance is too low because the amp will overheat and shut down first. The speaker that gets fried is usually one that’s an adequate impedance load for the amp.)

Conversely, you generally won’t get audible distortion if say, you had a comfortable input signal to your 8-ohm amp, but bogged it down with a 2-ohm load. The amp would sound clean up to the point where it overheated and shut down, with no clip indicator ever lighting up. It’s not uncommon these days to see people who are driving say 4-ohm speakers with a 6-ohm receiver. Naturally, the trade off is that they can’t push the system as hard as they would be able to if they had a better-suited amplifier, but we don’t see them complaining about distortion, even though they are obviously overloading the amplifier.

Thus the clip lights ultimately have little or no bearing on what’s happening with the rail voltage. They merely show that the amp’s input stage is being overdriven. Nevertheless, they should taken seriously.

Like many things with audio, I won’t claim this is a “hard and fast” thing. It’s a big world - there are all kinds of amplifier topologies out there, as well as all kinds of impedance loads. But at least this is how it’s traditionally been. I’m not up on all the latest gee-whiz amps with digital processing; it’s possible that they are able to show actual output clipping.

Regards,
Wayne A. Pflughaupt




Edited by Wayne A. Pflughaupt - 10/31/13 at 7:52pm
post #37 of 40
Quote:
Originally Posted by Wayne A. Pflughaupt View Post


Nope – the clip lights only show that the input signal is too high. For instance, unplug the load (speaker) from the amp and what happens to the clip indicators? Nothing – they will keep right on lighting.


Just because the indicators keep going if you disconnect the speakers doesn't inherently mean the input signal is too high from an overload standpoint nor that the clipping indicators are monitoring the inputs. There is still voltage present on the output terminals and the amp will still clip even with no load if the voltage swing capability is exceeded.

Many amps only need about 1.5V, give or take, to drive full output yet the input stages themselves don't actually overload until quite a bit higher. Take for instance the QSC PLX 3402s I use. They require 1.9V to drive full output at 8 ohms, yet the inputs don't clip until 10V. It doesnt make any sense to have clipping indicators to indicate clipping/overload of the inputs when the amp output would be clipping way before you got to 10V on the inputs.
Edited by whoaru99 - 10/31/13 at 8:10pm
post #38 of 40
Quote:
Originally Posted by Wayne A. Pflughaupt View Post


Nope – the clip lights only show that the input signal is too high. For instance, unplug the load (speaker) from the amp and what happens to the clip indicators? Nothing – they will keep right on lighting.

Not that the clip indicators are meaningless: If the amp’s inputs are clipping, then a square-wave signal is being sent to the amplifier section, and you’ll get audible distortion. However, the amp will keep going, with the clip indicators lit up like a Christmas tree, right up to the point where it fries the speaker – i.e., melts the voice coil. Why didn’t the amp shut down first? Because it wasn’t overloaded. That is, the current demand (determined by the impedance load) never exceeded the power supply’s capabilities. (Typically you won’t fry a speaker whose impedance is too low because the amp will overheat and shut down first. The speaker that gets fried is usually one that’s an adequate impedance load for the amp.)

Conversely, you generally won’t get audible distortion if say, you had a comfortable input signal to your 8-ohm amp, but bogged it down with a 2-ohm load. The amp would sound clean up to the point where it overheated and shut down, with no clip indicator ever lighting up. It’s not uncommon these days to see people who are driving say 4-ohm speakers with a 6-ohm receiver. Naturally, the trade off is that they can’t push the system as hard as they would be able to if they had a better-suited amplifier, but we don’t see them complaining about distortion, even though they are obviously overloading the amplifier.

Thus the clip lights ultimately have little or no bearing on what’s happening with the rail voltage. They merely show that the amp’s input stage is being overdriven. Nevertheless, they should taken seriously.

Like many things with audio, I won’t claim this is a “hard and fast” thing. It’s a big world - there are all kinds of amplifier topologies out there, as well as all kinds of impedance loads. But at least this is how it’s traditionally been. I’m not up on all the latest gee-whiz amps with digital processing; it’s possible that they are able to show actual output clipping.

Regards,
Wayne A. Pflughaupt





Wayne, and anyone else interested in the Peavey IPR2 amp...I have had an authority in the matter try to clarify and possibly correct any any misconceptions or misinformation. Hope this helps.

"the clip detector and clip limiter operate by monitoring the feedback loop. They do not monitor the input amplitude or power supply rail voltage. If there is excessive clipping, feedback increases dramatically. This is monitored by a clip detector circuit that sees the increased feedback, and activates a gain reduction cell to pull the amplifier's input level down. We do allow some clipping to 'fatten' up the sound. Time constants are a tradeoff between keeping things clean and sounding loud. The mids are kept relatively clean, the lows are allowed to square off more and toss in some harmonics. This is where an external limiter and the additional headroom of the 7.5 or 7500 come in handy. You choose your tradeoff.

Impedance issues are separate. These amps simply keep delivering current until they hit a trip point. The output stage shuts off for a second or two and cranks back up. This is temperature dependant. If the output MOSFETs are hot, they can handle less current safely and are shut down at a level less than what they can handle when cool. The amp will drive one ohm's worth of 18"s per channel until you push the MOSFETs into higher temperatures."
post #39 of 40
Thread Starter 
Good info and thanks for digging it up.

It sounds like all that person is saying is the clip lights are governed by a central detector circuit which monitors the noise that occurs when clipping happens vs. monitoring the input or output directly.

When I send too much signal to my AVR with the speakers unhooked I can hear audible noise coming from the AVR until it shuts itself off. To the point I know when it's going to shut off based off the noise I hear. I don't know if it's the same idea or not but it reminded me of that scenario.

RE: the one ohm bit. I believe Wayne pretty much says the same thing.

Seems kind of silly to put a one ohm load on an amp rated for 2ohms unless you have the extra headroom and are limited to a speaker ohm load of one. IE, can't configure your speakers any other way.
post #40 of 40
Quote:
Originally Posted by blah450 View Post

...This is monitored by a clip detector circuit that sees the increased feedback...

I guess that answers the question of clipping of what - anything (though I'm also of the mind that it's not likely at the input); wherever the clipping originates, feedback will try to correct the output signal.
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