# Exceeding an amps maximum input voltage



## storis (Feb 25, 2013)

I have a Kenwood XR-5s Amp, the specs in the owners manual say it's max input voltage is 5 volts. I want to install an Audio Control EQS Equalizer which has adjustable output voltage to a specified max of 13.5 volts. Audio Controls setup instructions say to leave the amp gains down (fully counter clockwise), and turn the output voltage on the EQS up until the 5 volt output LED comes on. 

I don't trust any manufacturer specs as far audio equipment is concerned, I would rather hook up a scope and get real values for the individual pieces of equipment that I own, than just trust the manufacturers general specs setup for the whole line of equipment. I would prefer to install the EQS into my system, connect a scope to the speaker terminals. Then while playing a pink noise test cd through the head unit, slowly turn the output voltage up until I see I have slightly exceeded the actual max voltage the amp can handle. 

My questions are; first and most importantly what will I see happen to the waveform on the scope when the max voltage of my amp is exceeded (for example distortion of the wave form or clipping), and how much excess input voltage can an amp handle without damage 5.1 volts, 6volts, 13.5 volts?


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## minbari (Mar 3, 2011)

most amplifiers have op amps of some kind on the preamp input. if you exeed that voltage you will just clip the input. what you will see is a clipped output. doubtfull it would do any permanent damage.


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## ceri23 (Aug 10, 2012)

minbari said:


> most amplifiers have op amps of some kind on the preamp input. if you exeed that voltage you will just clip the input. what you will see is a clipped output. doubtfull it would do any permanent damage.


...within reason.


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## minbari (Mar 3, 2011)

ceri23 said:


> ...within reason.


Well ya, if you put in 15, 20 volts you will likely hurt it. Most op amps are pretty tolerant .

Sent from my motorola electrify using digital farts


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## molsonice (Jul 15, 2012)

AFAIK Audiocontrol is pretty legit. I'd trust it if the light just comes on to be 5v. 

Why are you trying to crank it up so much? Shouldn't the amp have plenty of gain available?


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## storis (Feb 25, 2013)

I trust Audio Control more when they say the 5volt LED is actually 5volts at the output, than I do Kenwood, when they say 5volts is the max input voltage. Maybe the max input really isn't 5 volts maybe it's less maybe it's more. I just want to tune my system to get the most out of it without distortion or clipping.


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## minbari (Mar 3, 2011)

if you are really that concerned about it, then get an o-scope and set it up that way


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## storis (Feb 25, 2013)

I'm not trying to sound like a jerk, but thats what I said in my original post I would rather get an O-scope than just trust the manufacturers specs. I was mostly wondering what I would see on the scope connected to the speaker terminals, if I overloaded the input. I also want to be sure overloading the input slightly will not damage the amp.


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## minbari (Mar 3, 2011)

Lol, we're going in circles.

No slightly over diving the input won't matter.

If you have a scope on the out put of the amplifier and you either over drive the input or the out put on the amplifier. It will start to clip. Meaning the sine wave will start to flatten out.

Sent from my motorola electrify using digital farts


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## miniSQ (Aug 4, 2009)

storis said:


> I'm not trying to sound like a jerk, but thats what I said in my original post I would rather get an O-scope than just trust the manufacturers specs. I was mostly wondering what I would see on the scope connected to the speaker terminals, if I overloaded the input. I also want to be sure overloading the input slightly will not damage the amp.


 I bet YouTube will have a video showing a clipped signal.

I also think you are wasting your money buying an O Scope for this purpose...BUt I understand the desire to be thorough.


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## minbari (Mar 3, 2011)

You can get one of those dso LCD Scopes for like $60.

Sent from my motorola electrify using digital farts


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## storis (Feb 25, 2013)

Thanks, minbari and everyone else, that was what I wanted to know. I thought that was the answer I just wanted to verify it. I don't need to buy a scope I can get a real nice one from work for a few days to play around.


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## Dillyyo (Feb 15, 2008)

Seems like you're likely worrying about nothing since music is dynamic and you won't be delivering a steady 0dB signal to your amps. Anyone running their amps with literally no clipping is just wasting amp power and money, IMO.


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## mathematics (May 11, 2009)

what would you see on the scope while playing pink noise? a whole lot of nothing. you need the scope to tell you max and RMS voltage. the only way you'd see a clipped signal is if you play sine waves one at a time. hard to miss seeing a clipped signal. any good DMM will give you max and RMS voltages if you're looking to do it that way.



storis said:


> I'm not trying to sound like a jerk, but thats what I said in my original post I would rather get an O-scope than just trust the manufacturers specs. I was mostly wondering what I would see on the scope connected to the speaker terminals, if I overloaded the input. I also want to be sure overloading the input slightly will not damage the amp.


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## Thunderplains (Sep 6, 2009)

I look at it this way.. If i could keeps the gains on the amp completely turned down and run the HU at 90% and use the eqs to adjust the voltage output until distortion or clips, I would do that.. Would be nice to have the amps at zero gain.


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## mathematics (May 11, 2009)

that doesn't make sense. why wouldn't you run amplifier inputs at max unclipped voltage? there is no benefit for being below that level. the point to the input op-amps is to be at max level without clipping. if not, you're wasting money.



Thunderplains said:


> I look at it this way.. If i could keeps the gains on the amp completely turned down and run the HU at 90% and use the eqs to adjust the voltage output until distortion or clips, I would do that.. Would be nice to have the amps at zero gain.


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## minbari (Mar 3, 2011)

I guess I would want to know what you gain by having the amp gains all the way down? noise floor does go up slightly if you have them all the up, so I am not saying crank em. but if you have em half way to match the voltage you have from your HU, who cares? that is why they have adjustable gains.

if you have a HU that can honestly run 90% volume on the knob and still be clean, then you are in the minority. not to mention, what happens when you get a recording that is older or recorded more quietly. you have no room to turn it up to a reasonable listening level.


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## mathematics (May 11, 2009)

what are you going to do, run back to your amps and adjust the gains when you get a source that's recorded at a lower level? you make gain adjustments with a source that has the lowest recording you'd likely listen to. noise floor is meaningless unless you plan to crank the volume when nothing is playing. your options to reduce noise floor are DSP, proper shielding, and cooling. If you're adjusting gains to have certain noise floor characteristics, you have underlying problems that you need to solve. gains are set to match input voltage to the op-amp design. gains aren't volume controls. they are to be set for voltage matching. it doesn't matter if that's damn near 0 or all the way up as long as the voltage is matched. op-amps will not output a clipped signal if the input isn't clipped.



minbari said:


> I guess I would want to know what you gain by having the amp gains all the way down? noise floor does go up slightly if you have them all the up, so I am not saying crank em. but if you have em half way to match the voltage you have from your HU, who cares? that is why they have adjustable gains.
> 
> if you have a HU that can honestly run 90% volume on the knob and still be clean, then you are in the minority. not to mention, what happens when you get a recording that is older or recorded more quietly. you have no room to turn it up to a reasonable listening level.


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## minbari (Mar 3, 2011)

I assume you quoted me because you are agreeing?


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## mathematics (May 11, 2009)

just making a statement


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## Thunderplains (Sep 6, 2009)

I stand corrected.. I try to keep my amp gains low.. I make it a rule to stay in the 33% range. And no, they are not volume controls..


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## Dillyyo (Feb 15, 2008)

Thunderplains said:


> I look at it this way.. If i could keeps the gains on the amp completely turned down and run the HU at 90% and use the eqs to adjust the voltage output until distortion or clips, I would do that.. Would be nice to have the amps at zero gain.


Why would you want this? Your gain is to match input sensitivity with input signal. Anything lower than that ideal setting is just a waste of am amps potential and any setting that doesn't allow some clipping is IMO a waste of an amps max potential that still falls well within acceptable distortion levels.


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## Thunderplains (Sep 6, 2009)

Dillyyo said:


> Why would you want this? Your gain is to match input sensitivity with input signal. Anything lower than that ideal setting is just a waste of am amps potential and any setting that doesn't allow some clipping is IMO a waste of an amps max potential that still falls well within acceptable distortion levels.


As I said, I stand corrected.. In my situation, my amps did not need much gain to match the voltage.. It is simply an opinion and determined by one's setup, by no means the law..


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## boogeyman (Jul 1, 2008)

HEADROOM


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## ZAKOH (Nov 26, 2010)

This is a good question. Some amplifiers will not take excess input voltage kindly. Some will detect the excess input voltage and will either shut off or go into protect mode. Personally, I would simply calibrate the EQ with a DMM and a 0dB test tone not to exceed 4VAC, just to be safe, on its output with the head unit volume knob set on the level you do not plan to exceed.


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## 14642 (May 19, 2008)

In fact, setting your amplifier's input sensitivity to allow about 10dBof clipping (often referred to as "overlap" is a good idea. That means that for an input signal of 3.2V, you'd set the amp input sensitivity at 1V.


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## Oliver (Jun 25, 2007)

mathematics said:


> *gains are set to match input voltage* to the op-amp design. gains aren't volume controls. they are to be set for voltage matching. it doesn't matter if that's damn near 0 or all the way up as long as the *voltage is matched.* op-amps will not output a clipped signal if the input isn't clipped.


This guy ^^^^ or Andy


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## 14642 (May 19, 2008)

We're both right, actually. The problem with setting up a system that isn't allowed to clip at all is that music that's recorded without a lot of dynamic range compression won't sound very loud, and that's why the 10dB is helpful. You can get a much higher output without audible distortion because we don't hear distortion on music peaks very easily. 

In any case, you won't damage the inputs of your gear by dialing in this much additional gain. If you listen to Death Magnetic with the volume control all the way up, you may damage your speakers, though.


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## chad (Jun 30, 2005)

Andy Wehmeyer said:


> We're both right, actually. The problem with setting up a system that isn't allowed to clip at all is that music that's recorded without a lot of dynamic range compression won't sound very loud, and that's why the 10dB is helpful.


By this token then people wont' go out and buy kilowatt amps for their tweets because everyone knows "amp gain all the way down=Essque." Even if it makes absolutely no sense.


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## sphell (May 24, 2012)

No one has actually told you how to do it yet....

Play a 1khz tone recorded at 0dB and put the scope on your headunit's RCA output. Turn up the volume until you see the waveform clip, now back it off until you see a nice smooth waveform again. That is your headunit's max unclipped volume. Leave it at this volume and next do the same with the Audiocontrol output. Take note of when you hit 5V on the outputs. 

Hook up your Kenwood amp with minimum gain set, and put the scope on the speaker outputs. Check if there is any clipping. If not, turn up the gain slowly on the Audiocontrol again until you see clipping at the amp's speaker terminals. 

Go back and measure the output voltage on the Audiocontrol, whatever it reads is the max input voltage the Kenwood amp will accept.


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## dogsbark26 (Feb 10, 2009)

Welcome sphell. What a great first post! Thank you.


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## customtronic (Jul 7, 2007)

sphell said:


> No one has actually told you how to do it yet....
> 
> Play a 1khz tone recorded at 0dB and put the scope on your headunit's RCA output. Turn up the volume until you see the waveform clip, now back it off until you see a nice smooth waveform again. That is your headunit's max unclipped volume. Leave it at this volume and next do the same with the Audiocontrol output. Take note of when you hit 5V on the outputs.
> 
> ...


Well put. That's the way I've always seen it done.


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## 14642 (May 19, 2008)

Sorry, this is almost all wrong, from my perspective. 

YOU WANT SOME CLIPPING! If you set your system up so that nothing ever clips, you're giving up TONS of useable volume unless you listen with the volume control all the way up all the time. Make yourself a sine wave CD or get the Autosound 2000 test disc and follow the instructions. Use a track recorded at 0dbB to set the input sensitivity on your signal processor. Make sure the EQ is flat. Then, to set the output gain of the processor and the input sensitivity of the amplifiers using tracks recorded at -10dB. If you want the input sensitivity control on your amp all the way down, then set it there (5V) and turn up the output of the EQ until you see clipping. IF the processor actually puts out 13.5V RMS, then with it all the way up and the amp sensitivity all the way down, you'll have 8.6dB of "overlap" (that will allow 8.6dB of clipping). 

You want this. Trust me.


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## t3sn4f2 (Jan 3, 2007)

Andy Wehmeyer said:


> Sorry, this is almost all wrong, from my perspective.
> 
> YOU WANT SOME CLIPPING! If you set your system up so that nothing ever clips, you're giving up TONS of useable volume unless you listen with the volume control all the way up all the time. Make yourself a sine wave CD or get the Autosound 2000 test disc and follow the instructions. Use a track recorded at 0dbB to set the input sensitivity on your signal processor. Make sure the EQ is flat. Then, to set the output gain of the processor and the input sensitivity of the amplifiers using tracks recorded at -10dB. If you want the input sensitivity control on your amp all the way down, then set it there (5V) and turn up the output of the EQ until you see clipping. IF the processor actually puts out 13.5V RMS, then with it all the way up and the amp sensitivity all the way down, you'll have 8.6dB of "overlap" (that will allow 8.6dB of clipping).
> 
> You want this. Trust me.


^ x2


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## Dillyyo (Feb 15, 2008)

chad said:


> By this token then people wont' go out and buy kilowatt amps for their tweets because everyone knows "amp gain all the way down=Essque." Even if it makes absolutely no sense.


I don't even know how this came into practice over the years, but everyone and their brother seem to follow the same mantra. I wonder if it's an offshoot of the golden ear crowd? :laugh:


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## Dillyyo (Feb 15, 2008)

Andy Wehmeyer said:


> Sorry, this is almost all wrong, from my perspective.
> 
> YOU WANT SOME CLIPPING! If you set your system up so that nothing ever clips, you're giving up TONS of useable volume unless you listen with the volume control all the way up all the time. Make yourself a sine wave CD or get the Autosound 2000 test disc and follow the instructions. Use a track recorded at 0dbB to set the input sensitivity on your signal processor. Make sure the EQ is flat. Then, to set the output gain of the processor and the input sensitivity of the amplifiers using tracks recorded at -10dB. If you want the input sensitivity control on your amp all the way down, then set it there (5V) and turn up the output of the EQ until you see clipping. IF the processor actually puts out 13.5V RMS, then with it all the way up and the amp sensitivity all the way down, you'll have 8.6dB of "overlap" (that will allow 8.6dB of clipping).
> 
> You want this. Trust me.


x3! ^ People must have a lot of money to waste.


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## customtronic (Jul 7, 2007)

Andy Wehmeyer said:


> Sorry, this is almost all wrong, from my perspective.
> 
> YOU WANT SOME CLIPPING! If you set your system up so that nothing ever clips, you're giving up TONS of useable volume unless you listen with the volume control all the way up all the time. Make yourself a sine wave CD or get the Autosound 2000 test disc and follow the instructions. Use a track recorded at 0dbB to set the input sensitivity on your signal processor. Make sure the EQ is flat. Then, to set the output gain of the processor and the input sensitivity of the amplifiers using tracks recorded at -10dB. If you want the input sensitivity control on your amp all the way down, then set it there (5V) and turn up the output of the EQ until you see clipping. IF the processor actually puts out 13.5V RMS, then with it all the way up and the amp sensitivity all the way down, you'll have 8.6dB of "overlap" (that will allow 8.6dB of clipping).
> 
> You want this. Trust me.


Thanks for the post Andy. I've been doing this for 20 years but am always learning. If I'm doing something wrong or there's a better way to do it I like to know. :thumbsup:


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## mathematics (May 11, 2009)

Just so there's no misconceptions out there, clipping damages speakers, not amps.


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## t3sn4f2 (Jan 3, 2007)

mathematics said:


> Just so there's no misconceptions out there, clipping damages speakers, not amps.


Too much power damages speakers, not clipping. Clipping is part of modern overly compressed pop music. Does pop music damage speakers then?


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## mathematics (May 11, 2009)

I didn't say it was the only cause of damaged speakers. Of course over powering them causes damage. Play square waves through your speakers and let me know how they hold up. The DC component of a clipped signal causes motor damage. 




t3sn4f2 said:


> Too much power damages speakers, not clipping. Clipping is part of modern overly compressed pop music. Does pop music damage speakers then?


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## minbari (Mar 3, 2011)

mathematics said:


> I didn't say it was the only cause of damaged speakers. Of course over powering them causes damage. Play square waves through your speakers and let me know how they hold up. The DC component of a clipped signal causes motor damage.


As long as the power under the curve is under under thermal limit of the speaker, you can run a square wave all day

Sent from my motorola electrify using digital farts


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## t3sn4f2 (Jan 3, 2007)

mathematics said:


> I didn't say it was the only cause of damaged speakers. Of course over powering them causes damage. Play square waves through your speakers and let me know how they hold up. The DC component of a clipped signal causes motor damage.


http://www.diymobileaudio.com/forum/general-car-audio-discussion/87065-underpowering-sub-3.html

Start with MarkZ's post (#30) and read on till the end. Primarily his post though.


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## molsonice (Jul 15, 2012)

Just thought I'd mention I got one of those Steve Meade distortion detectors. Really made things simple not having to mess with an o scope. Wish I had one of these 10yrs ago lol.

If I recall they recommended using a -5db signal for gain overlap for mids/tweets, and a -10db or even -15db signal for setting subs. But of course theres nothing wrong with less if you want to limit power output.


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## squeak9798 (Apr 20, 2005)

mathematics said:


> I didn't say it was the only cause of damaged speakers. Of course over powering them causes damage. Play square waves through your speakers and let me know how they hold up. The DC component of a clipped signal causes motor damage.


There's no DC component to a clipped signal. It's all AC. And the clipping doesn't damage the speaker, exceeding the thermal or mechanical limits of the speaker does. A true squarewave will have twice the average power than a sinewave of the same peak voltage, but as long as the average power is still below the thermal and mechanical limits of the speaker then nothing will be damaged.


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## 14642 (May 19, 2008)

Right. For the thousandth time, distortion doesn't damage speakers. Too much power for too long causes damage from heat. Way too much power for a short time may cause mechanical failure.


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## chad (Jun 30, 2005)

Andy Wehmeyer said:


> Right. For the thousandth time, distortion doesn't damage speakers. Too much power for too long causes damage from heat. Way too much power for a short time may cause mechanical failure.


********, not in car audio. Everything is different here. Ask the internet or some dude stuck in the 90's.


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## Dillyyo (Feb 15, 2008)

mathematics said:


> I didn't say it was the only cause of damaged speakers. Of course over powering them causes damage. Play square waves through your speakers and let me know how they hold up. The DC component of a clipped signal causes motor damage.


There are no actual square waves in a clipped signal and there is no DC component.


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## cleansoundz (May 14, 2008)

Good thread. Subscribed.


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## left channel (Jul 9, 2008)

Wait, I thought we already determined in that bazillion page thread on clipping that is was Alternating DC.... sarcastically rolling eyes now... 



Dillyyo said:


> There are no actual square waves in a clipped signal and there is no DC component.


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