What can I change to get full power out of my amp? - AVS Forum
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post #1 of 69 Old 03-23-2014, 04:54 PM - Thread Starter
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Sooooo, I have a Peavey IPR2 7500 and I seem to be having an issue with the DDT (clipping) lights coming on prematurely.

So I decided to test out a woofer that my dad got. It's a B&W 15, with single a 4" VC at 4 ohms.



So I had it hooked up to one channel of the amp with the amp gain all the way up. I have the sub out on the receiver at -7.5 going to a Samson S-Convert with the gain on that all the way up. I was getting the clipping lights and so I turned the sub out on the receiver up to 0 yet I would reach the same volume on the sub and get the clip lights. I tried messing with the gain on the amp and the s convert but nothing. The cabinet is 2.2 cubic feet. Here is a small video of the proceedure. I'm supposed to get 2400 watts into one channel at 4 ohms. If this is 2400 watts I'm in trouble.

http://s681.photobucket.com/user/saabracer32/media/Mobile%20Uploads/trimFB19CA82-AA5A-4406-A0A1-E98E756F9081.mp4.html

Dan
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post #2 of 69 Old 03-23-2014, 04:58 PM - Thread Starter
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If anyone has trouble with the video let me know. I had issues uploading it to YouTube so I was stuck with photobucket.
Dan

Oh one other thing I should mention. At the point of the amp clipping my bedroom lights are dimming pretty heavily. Not sure if that would be a cause of clipping or not. The amp will be getting a dedicated circuit in about a month or so.
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post #3 of 69 Old 03-23-2014, 05:48 PM
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My guess would be voltage drop. The amp is probably not getting enough power from the outlet.
If your lights are dimming, I am surprised the breaker is not tripping.

You could verify the voltage drop/line sag by trying amp in another area of the house if that is possible.

Also, if you have a multimeter you could test the outlet to see if you are even getting close to 120v before and after having the amp run.

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post #4 of 69 Old 03-23-2014, 06:02 PM
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post #5 of 69 Old 03-23-2014, 06:31 PM
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It looks like to me that you could be using all the amplifier has, you are driving that woofer hard enough with those 40 to 60hz burps.

You might thermal that woofer before hitting xmech at those frequencies (especially on like dubstep etc), and/or if any deep bass does come along... you might bottom it out too.

That in combination with the voltage drop, would clip it.
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post #6 of 69 Old 03-23-2014, 06:40 PM
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Possibly also eliminate S-convert from chain? Drive amp with just AVR and see what happens?
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post #7 of 69 Old 03-23-2014, 07:09 PM - Thread Starter
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My wife has a bit of a headache so I'll wait until tomorrow to check my voltage with a multimeter.

I would love to get rid of the s convert as I'm a believe of having the least amount in the signal chain. Without it I get very little output.

I got the amp as I was told it would be a perfect match to four UM 18s. After this I'm afraid that it might not drive them all that much. Gorilla83 (I think that's his name) and a few others have said the 7500 was too much power for 4 of the Dayton HO 18s so I know it has the potential.

Man I'm really hoping it's the voltage of the outlet.

Dan
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post #8 of 69 Old 03-23-2014, 07:22 PM
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Quote:
Originally Posted by saabracer23 View Post

Sooooo, I have a Peavey IPR2 7500 and I seem to be having an issue with the DDT (clipping) lights coming on prematurely.
That's a common problem with Peavey DDT. I've seen many reports from users trying to set their output voltage limit and they can't get near to what the amp should be capable of delivering before the DDT engages. I haven't seen any cures.

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post #9 of 69 Old 03-23-2014, 07:29 PM
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Keep in mind, as noted above, you're limited by your supply circuit. Assuming you're using a residential 120V receptacle.

15A: 120V * 15A * 0.9(efficiency) / 2(channels) = 810 W/ch
20A: 120V * 20A * 0.9 / 2 = 1080 W/ch
30A: 120V * 30A * 0.9 / 2 = 1620 W/ch

You cannot truly reach the potential of that amplifier until you use a 240V circuit. I'm not sure if the Peavey has a switchable input voltage. Also, I'm not sure of the units power supply design and if using only one channel would increase the output significantly.
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post #10 of 69 Old 03-23-2014, 08:12 PM - Thread Starter
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Quote:
Originally Posted by Bill Fitzmaurice View Post

That's a common problem with Peavey DDT. I've seen many reports from users trying to set their output voltage limit and they can't get near to what the amp should be capable of delivering before the DDT engages. I haven't seen any cures.

Bummer, no way to disengage it?
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Originally Posted by whitey019 View Post

Keep in mind, as noted above, you're limited by your supply circuit. Assuming you're using a residential 120V receptacle.

15A: 120V * 15A * 0.9(efficiency) / 2(channels) = 810 W/ch
20A: 120V * 20A * 0.9 / 2 = 1080 W/ch
30A: 120V * 30A * 0.9 / 2 = 1620 W/ch

You cannot truly reach the potential of that amplifier until you use a 240V circuit. I'm not sure if the Peavey has a switchable input voltage. Also, I'm not sure of the units power supply design and if using only one channel would increase the output significantly.

There isn't a significant jump by using only one channel, only like 100-200 watts. I have no problem running 240 volts to run an amp, though I don't think the peavey will do it. I'll test my voltage and then run the amp on a dedicated 20 amp circuit. If that doesn't work then maybe I should sell it.

Any suggestions for a 240v amp that will put out rated power other than the sanway clone?

Dan
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post #11 of 69 Old 03-24-2014, 02:21 AM
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Dan...something is off.
You have a few things to begin looking at....power supply at wall...wiring...AVR...faulty 7500...gain...etcetera.
First off, would like to see amp's performance on a dedicated 120V line.

Let's put it this way...I am in NY and have a dedicated 20 amp line for my amps.

Up to recently, I was running two Dayton 460HOs (4 ohm) in 4 cu ft sealed boxes, using forty-foot 12 gauge speaker wire runs...and wired the pair of subs in parallel to present a 2-ohm load to one amp channel of my Peavey IPR2 5000.
Then, I had my other pair of identical Dayton subs configured the same way and wired to the amp's second channel.
I had absolutely no problem driving amp with my Denon AVR and getting frickin' awesome bass at -10 volume during scenes from Master & Commander (ship/cannon battle) or WotW pod scene, amongst so many others...DDT lights flickered here and there at heaviest-demand scenes.

Of course, you are running a 7500, so my experience could not correlate 100% with your situation, but it comes close to what you should be able to do.
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post #12 of 69 Old 03-24-2014, 02:27 AM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

That's a common problem with Peavey DDT. I've seen many reports from users trying to set their output voltage limit and they can't get near to what the amp should be capable of delivering before the DDT engages. I haven't seen any cures.

Bill...all of these reports in the field?...or could you share a few public forums/threads where these many reports are referenced??
If in the field, do the many reports involve the DDT as it is implemented in the IPR2 series of Peavey amps?
Thanks in advance.
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Lastly, what is this 'Thumbs Up" thing?

Yesterday, it indicated I had 124 of them. Today it indicates 72. Did I tick someone off and they took back the "thumbs up" they had given me in a matter of just the last 8 hours? rolleyes.gif

Just eliminate the thing...enough already!
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post #14 of 69 Old 03-24-2014, 05:10 AM
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I am currently driving 4 SI18D2's in stereo 2 ohm with my IPR7500 and have never seen the DDT lights come on yet. The drivers have to be nearing max excursion though. They move much more than when I was driving 4 of them with an old EP2500 that's for sure.

Simplify the circuit. Let your receiver drive the amp directly and verify the output voltage from the receiver. Set the level back to 0db at the sub output and depending on your receiver you should get at least 2V from the output when at 0db output. My Denon X4000 will put out nearly 8V at full tilt.
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post #15 of 69 Old 03-24-2014, 05:20 AM
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Quote:
Originally Posted by whitey019 View Post

Keep in mind, as noted above, you're limited by your supply circuit. Assuming you're using a residential 120V receptacle.

15A: 120V * 15A * 0.9(efficiency) / 2(channels) = 810 W/ch
20A: 120V * 20A * 0.9 / 2 = 1080 W/ch
30A: 120V * 30A * 0.9 / 2 = 1620 W/ch

You cannot truly reach the potential of that amplifier until you use a 240V circuit. I'm not sure if the Peavey has a switchable input voltage. Also, I'm not sure of the units power supply design and if using only one channel would increase the output significantly.

The amp will draw more power when it needs it with regular program material. Even though the above numbers are correct, a 20 amp outlet will easily yield 100 amps for up to a second without tripping. So, for transients it should be drawing much more power than the nominal 1080w per channel.
Of course, that is predicated on the fact that there is power to be drawn. If there is line sag/voltage drop it will be much less.




Now for sine wave testing you will be limited by the breaker very quickly.
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post #16 of 69 Old 03-24-2014, 06:15 AM
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Quote:
Originally Posted by blah450 View Post

Bill...all of these reports in the field?...or could you share a few public forums/threads where these many reports are referenced??
If in the field, do the many reports involve the DDT as it is implemented in the IPR2 series of Peavey amps?
Thanks in advance.
It's been reported on my forum, and it's not specific to this amp but to Peavey in general with DDT.

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post #17 of 69 Old 03-24-2014, 09:48 AM
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Originally Posted by jpmst3 View Post

My guess would be voltage drop. The amp is probably not getting enough power from the outlet.
If your lights are dimming, I am surprised the breaker is not tripping.

You could verify the voltage drop/line sag by trying amp in another area of the house if that is possible.

Also, if you have a multimeter you could test the outlet to see if you are even getting close to 120v before and after having the amp run.

Question on how to test it. I presume you test the outlet first and see if you have 120v, then plug the amp in one of the 2 sockets and play something at the level that dims the lights and check the other socket to see if the voltage is dropping? Is this correct?

I am having the light dimming issue and it feels like the amp should be giving more as well. I am using an inuke3000.
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post #18 of 69 Old 03-24-2014, 11:01 AM
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Originally Posted by cessna1466u View Post

Question on how to test it. I presume you test the outlet first and see if you have 120v, then plug the amp in one of the 2 sockets and play something at the level that dims the lights and check the other socket to see if the voltage is dropping? Is this correct?

I am having the light dimming issue and it feels like the amp should be giving more as well. I am using an inuke3000.

Yes, that should work.

You can use a kill-a-watt as well, but they often don't have the ability to save the high and low points. So, if the voltage varies wildly it may not pick up data fast enough. Hopefully, you can find something that works for you.

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post #19 of 69 Old 03-24-2014, 11:12 AM
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Quote:
Originally Posted by cessna1466u View Post

Question on how to test it. I presume you test the outlet first and see if you have 120v, then plug the amp in one of the 2 sockets and play something at the level that dims the lights and check the other socket to see if the voltage is dropping? Is this correct?

I am having the light dimming issue and it feels like the amp should be giving more as well. I am using an inuke3000.

That'll work, be careful.
Also, to make things easier, you can plug a short extension cord in to facilitate easier and more comfortable access to the circuit measurements.

A Kill-a-Watt brand meter is handy for such measurements, iirc, Frys and other places offer them. Of course a multimeter is fine, just exercise caution.

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Yes, first thing you have to do is get proper electrical service to the amp. Dimming lights is indicative of a circuit reaching it's capacity, especially on peak delivery.

Second, the gain of an amplifier is fixed, in case of the IPR2 7500, it is x40(32db). The attenuator controls(volume knobs) merely allow adjustment of the voltage of the incoming signal to allow full rated power delivery from the amp, and give you the best signal to noise ratio through the device.

I also trust you have the dip switches on the back set to either "full" or "subwoofer", otherwise you're not getting any low frequency content to the subs at all.

Best regards,

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post #21 of 69 Old 03-24-2014, 12:01 PM
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Looks like I might be ok, I think. So with nothing plugged in to the outlet, just with all the lights on that are on that breakers (15amp) I get 121.2 as the reading. I plugged in the Monster Cable power conditioner to the plug (the only thing plugged in to the pluggs on this outlet is the power conditioner and a phone charger). When playing at reference level a test tone of 20hz, 30hz and 40hz I get no dimming at all and the meter reads between 119.1-120.4. When I play something like a movie or audio file with a lot of bass I get it doesn't go down below the 119.1 but I do get some dimming which is weird. So I think I am ok since even with playing the test tones at high volumes to find and isolate noises I never tripped the breaker.

Who needs lights anyways. I can just keep them turned off and will never see them dimming.biggrin.gif
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post #22 of 69 Old 03-24-2014, 12:04 PM
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Quote:
Originally Posted by cessna1466u View Post

Looks like I might be ok, I think. So with nothing plugged in to the outlet, just with all the lights on that are on that breakers (15amp) I get 121.2 as the reading. I plugged in the Monster Cable power conditioner to the plug (the only thing plugged in to the pluggs on this outlet is the power conditioner and a phone charger). When playing at reference level a test tone of 20hz, 30hz and 40hz I get no dimming at all and the meter reads between 119.1-120.4. When I play something like a movie or audio file with a lot of bass I get it doesn't go down below the 119.1 but I do get some dimming which is weird. So I think I am ok since even with playing the test tones at high volumes to find and isolate noises I never tripped the breaker.

Who needs lights anyways. I can just keep them turned off and will never see them dimming.biggrin.gif

Good deal!
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post #23 of 69 Old 03-24-2014, 12:14 PM
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Perhaps you are not catching the voltage dips with your measurement method and meter.

It would take sustained levels, like test tones or similar program materials, the Olympus Has Fallen scene, for example ... or similarly demanding deep test tones, that would allow your meter to catch the issue.


Curious about the reason for the voltage drop.. long or undersized run? Loaded circuit? Loaded main?

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post #24 of 69 Old 03-24-2014, 07:52 PM - Thread Starter
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So I tested my voltage today and it seems ok. I used a fluke 27 for measurements. Only the amp was plugged into the receptacle. With the amp off I was reading 121.4, turn amp on with nothing playing and no change. Playing black cow by steely dan (same song as in the video) to the point of DDT lights coming on and major dimming on the lights I was still reading between 119.4-120.8 with it fluctuating. I took the Samson out of the chain and the DDT lights never came on!!!!!! But it was playing very quietly haha. So I had to add the box back in.

Not sure where to go next. I have an extra electrical box, 20 amp receptacle, and 20 feet of 12-2 so I'm thinking I might make an "extension cord" of sorts that will hook up directly to a 20 amp breaker in the panel. That way I can definitely eliminate the power source as the issue.

So where do I go next? Is there a way to test actual power output of the amp? I just find it odd that there are those who are pushing 4 18s to xmax without the DDT lights coming on, yet I can't push a single 15 that far.

Ugh, would a pro like to come setup my system lol? Sad thing is, I have one more unit to add to the signal chain, a Velodyne SMS-1.

Dan
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post #25 of 69 Old 03-24-2014, 08:33 PM
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Quote:
Originally Posted by saabracer23 View Post

So I tested my voltage today and it seems ok. I used a fluke 27 for measurements. Only the amp was plugged into the receptacle. With the amp off I was reading 121.4, turn amp on with nothing playing and no change. Playing black cow by steely dan (same song as in the video) to the point of DDT lights coming on and major dimming on the lights I was still reading between 119.4-120.8 with it fluctuating. I took the Samson out of the chain and the DDT lights never came on!!!!!! But it was playing very quietly haha. So I had to add the box back in.

Not sure where to go next. I have an extra electrical box, 20 amp receptacle, and 20 feet of 12-2 so I'm thinking I might make an "extension cord" of sorts that will hook up directly to a 20 amp breaker in the panel. That way I can definitely eliminate the power source as the issue.

So where do I go next? Is there a way to test actual power output of the amp? I just find it odd that there are those who are pushing 4 18s to xmax without the DDT lights coming on, yet I can't push a single 15 that far.

Ugh, would a pro like to come setup my system lol? Sad thing is, I have one more unit to add to the signal chain, a Velodyne SMS-1.

Dan

Your circuit in the bedroom is most assuredly a 15amp, and probably not enough current available for that 7500.

Don't run a circuit from the panel with only two conductors, please use three, so you'll have the extra safety.

I am also hunching that smallish sealed 2.2 cuft cabinet is not anywhere near a correct alignment for that woofer.

Best regards,

John
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post #26 of 69 Old 03-24-2014, 08:58 PM
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I can plug my crown xti 4002 into a 20 amp outlet 5 feet from the breaker at some venues and see significant voltage drop when I lean on it hard at 4 ohms per channel (with 3 db of clipping). I can monitor this using this utility in system architect while in use. when pushed to this level its not uncommon for me to see the voltage meter drop to the high 90s (on 15 amp circuits), and the low 100s when on a 20 amp circuits (with close proximity to the main breaker, and less than 5 feet of 12 gauge cable terminated in IEC).





When I notice lots of voltage drop, I notice that the amp "clips" much earlier (sometimes even 10db too early). I believe this has something to do with inrush current limiting (low voltage means higher current to supply the same wattage).
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post #27 of 69 Old 03-24-2014, 09:34 PM - Thread Starter
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Quote:
Originally Posted by servojohn View Post

Your circuit in the bedroom is most assuredly a 15amp, and probably not enough current available for that 7500.

Don't run a circuit from the panel with only two conductors, please use three, so you'll have the extra safety.

I am also hunching that smallish sealed 2.2 cuft cabinet is not anywhere near a correct alignment for that woofer.

Best regards,

John

Yes the bedroom is 15 amp, buy wouldn't it just trip the breaker if it wasn't enough?

In electrical wiring they never include the ground wire, so 12/2 actually has 3 wires, hot, neutral, and ground. 12/3 has ground, neutral, and two hots (or one hot and a common wire,if being used in a way such as a 3 way switch)

The 2.2 cruft cabinet is small I'm sure, I just built it to spec of B&W's cabinet. I'm sure they used a bit of eq.

Dan
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post #28 of 69 Old 03-24-2014, 09:36 PM - Thread Starter
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Quote:
Originally Posted by BadmanSound View Post

I can plug my crown xti 4002 into a 20 amp outlet 5 feet from the breaker at some venues and see significant voltage drop when I lean on it hard at 4 ohms per channel (with 3 db of clipping). I can monitor this using this utility in system architect while in use. when pushed to this level its not uncommon for me to see the voltage meter drop to the high 90s (on 15 amp circuits), and the low 100s when on a 20 amp circuits (with close proximity to the main breaker, and less than 5 feet of 12 gauge cable terminated in IEC).





When I notice lots of voltage drop, I notice that the amp "clips" much earlier (sometimes even 10db too early). I believe this has something to do with inrush current limiting (low voltage means higher current to supply the same wattage).

Hmmm is there a better way to monitor my voltage? I wasn't seeing much of a drop at all when the DDT lights came on. Would it be better to go with a 30 amp breaker than 20. Will it help me in any way?

Dan
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post #29 of 69 Old 03-24-2014, 10:01 PM
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i wonder if you are clipping your signal before it is going into your amp, then your amp is clipping as it tries to work with the dc necessary to produce a square wave. it is tough to tell from the vid, but the bass sounds both clipped and weak. what is your signal chain from the source?

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post #30 of 69 Old 03-24-2014, 10:15 PM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post

i wonder if you are clipping your signal before it is going into your amp, then your amp is clipping as it tries to work with the dc necessary to produce a square wave. it is tough to tell from the vid, but the bass sounds both clipped and weak. what is your signal chain from the source?

That's what I was thinking as well. So I have it playing a cd through a pioneer elite DVD player out optical to my yamaha RX-V3000 receiver. I have the mains set to small and LFE set to sub only (I chose this as it said I would get the most voltage output from the sub out, wanted to see if I could run it without the bump box). So the manual says I should get 4.0v this way. So I have sub set to -7.5 (scale of -10 to 0) and I'm using rca's to the Samson s-convert. From the s convert I'm using the XLR cables out to the input of my amp. The bump box gain is all the way up (set to 0 I believe). The gain on the amp is all the way up, the switch on the back of the amp is set to subwoofer on both channels. I'm using speakon connectors. They are the 4 conductor style, but I believe with this amp you can only utilize two per channel (although on channel one it says you can use it for output one and two which is a bit confusing)

I read online that it was common practice to set the bump box and amp gain all the way up and attenuate using the sub out level on the receiver. I've messed with the gain levels on both with no luck.

My first thought when I experienced this was that the signal going into the amp was clipping.

Any other thoughts or procedures I should go through to weed out the possibilities? I'm not too familiar with using pro gear.

Dan
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