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Is my cab clipping?

B

Bass_masta16

Jul 9, 2008
1,084
3
32
Wellington, Ontario, Canada
#1
Here it is..


I have a Hartke LH1000 with an Ampeg SVT-410HE and I can turn the volume all the way and it won't make the noise (I'm am just using the normal output, so it's only 225 watts). But when I hook my Zakk Wylde distortion pedal up to it, and turn it to about 5, it make's a weird noise.. it kind of sounds like normal distortion, but at the same time, it sounds like something might be up. This only happens when I hit my strings with moderate to heavy force, but if I barely touch them, it's clean.


So can anyone help me with this, just tell me if it's the distortion or the amp/cab clipping? (I don't really KNOW what clipping is, I just assume that it might be this)


Thanks,
Josh
 
#2
Check your battery on your pedal... Also cabs dont clip, amps do. IIRC when an amp clips, it actually clips the top of the signal, if viewed on an oscilliscope. When this happens the amp can send DC current to the speakers possibly cooking the voice coils.:crying:
 
#3
Of course it's your cab clipping. If you crank your amp up, then add a distortion and crank it up, too, you can go wildly past what that cab can handle. You're supposed to set your effects at roughly the same volume level as when you run your amp clean, which is already insane enough. Calm down with the volume before you have to pay hundreds of dollars to get the cab fixed.

Bassfishin, do a search on amp clipping and underpowering, and you will find out why everything you said is false. Not your fault...there are many companies that still act like it's true, but it's 100% false. Speakers can clip (though not for long before they blow), and the only time an amp sends DC to the voice coils is when it's tremendously broken. DC never gets sent to the voice coils when an amp clips.
 
#4
bassfishin said:
Check your battery on your pedal... Also cabs dont clip, amps do. IIRC when an amp clips, it actually clips the top of the signal, if viewed on an oscilliscope. When this happens the amp can send DC current to the speakers possibly cooking the voice coils.:crying:
Click to expand...

All of the above information is incorrect, except checking batteries and DC having the capability to fry voice coils.

1) Cabs can clip. If you try to put more than they can handle into them, speakers will distort. You don't see it as much in the bass world (we usually just hit x-max, which sounds like farting), but a lot of guitarists rely on the sound of speaker distortion for their tone.

2) The tops and bottoms of the waves getting squared or rounded down is how ANYTHING clips. If this was inherently harmful to speakers, we wouldn't be able to use distortion or square-wave synthesizers of any sort.

3) If your amp is leaking significant amounts of DC through the speaker outs, there is something HORRIBLY wrong with the output section of your amp and it should be taken in for service right away.

To the OP, you can check if it's the speakers producing the anomaly in the signal by setting everything as you would normally use it, then turn the Master Volume on the amp down to a fairly low volume - say, apartment levels. If the anomaly is still present, it's something before the output stage that's producing it. If it's not present after turning down, either your power amp was clipping or your speakers were clipping.
 
#5
Bassfishin, do a search on amp clipping and underpowering, and you will find out why everything you said is false. Not your fault...there are many companies that still act like it's true, but it's 100% false.
Click to expand...

JimmyM:
Did a quick search on "speaker clipping". Not much comes up other than a few things related to car stereo. But when "amp clipping" is searched, there is a ton of info on it due to the fact that the term "clipping" in audio refers to amplifiers, not speakers. Speakers can run into problems such as "over-excursion". Here is a quick google searched find on amp clipping... :rollno:
" Musical transients, those instant bursts of musical information that are loud, can cause an amp to reach its operating limits. When that happens, the sound wave from the amp is corrupted and it can take the speaker out of its operating limits, thus causing damage to the speaker. It can be seen on an ocilliscope because a square sine wave will become jagged when the amp clips".
 
#6
JimmyM said:
Of course it's your cab clipping. If you crank your amp up, then add a distortion and crank it up, too, you can go wildly past what that cab can handle. You're supposed to set your effects at roughly the same volume level as when you run your amp clean, which is already insane enough. Calm down with the volume before you have to pay hundreds of dollars to get the cab fixed.

Bassfishin, do a search on amp clipping and underpowering, and you will find out why everything you said is false. Not your fault...there are many companies that still act like it's true, but it's 100% false. Speakers can clip (though not for long before they blow), and the only time an amp sends DC to the voice coils is when it's tremendously broken. DC never gets sent to the voice coils when an amp clips.
Click to expand...

When I have my amp cranked without the pedal on, it doesn't do anything. But when I have the amp on about 3-5 and play moderate to aggressively with the pedal on, it make's the noise
 
#7
Bass_masta16 said:
When I have my amp cranked without the pedal on, it doesn't do anything. But when I have the amp on about 3-5 and play moderate to aggressively with the pedal on, it make's the noise
Click to expand...
Right. Because your pedal is probably way louder than when you run clean and boosting the frequencies that cause your speakers to blow the quickest. Trust me...it's not good when speakers blow.

Bassfishin, I'm not up for a battle of semantics tonight. Call it clipping, over-excursion, whatever. The end result is the same...a blown speaker.

Let's look at this one sentence that you posted about musical transients, though:

"Musical transients, those instant bursts of musical information that are loud, can cause an amp to reach its operating limits. When that happens, the sound wave from the amp is corrupted and it can take the speaker out of its operating limits, thus causing damage to the speaker."

The operative phrase here is "it can take the speaker out of its operating limits." Taking the speaker out of its operating limits is what blows it, not the mere act of the amp clipping. If that were the case, you couldn't use a fuzz pedal or a synthesizer without blowing your speakers every time. The sound wave can be corrupted all day long and as long as it's in the safe handling range of the speaker, it's fine.
 
#8
Nick Kay said:
All of the above information is incorrect, except checking batteries and DC having the capability to fry voice coils.

1) Cabs can clip. If you try to put more than they can handle into them, speakers will distort. You don't see it as much in the bass world (we usually just hit x-max, which sounds like farting), but a lot of guitarists rely on the sound of speaker distortion for their tone.

2) The tops and bottoms of the waves getting squared or rounded down is how ANYTHING clips. If this was inherently harmful to speakers, we wouldn't be able to use distortion or square-wave synthesizers of any sort.

3) If your amp is leaking significant amounts of DC through the speaker outs, there is something HORRIBLY wrong with the output section of your amp and it should be taken in for service right away.
Click to expand...

Nick, I invite you to read this Link Removed You too Jimmy
 
#9
bassfishin said:
Nick, I invite you to read this Link Removed
Click to expand...
It's a load of crap. Amps do not pass DC voltages to the speakers under any circumstances unless they're broken. Period. And they certainly don't do it because of clipping. This guy needs his internet license revoked. Sorry to be the one to break it to you, but coming up with a fancy name and showing a lot of diagrams doesn't make the information presented true.
 
#12
Nope. Boost pedals do that. Distortion pedals, as far as I know anyway, take your signal and distort it in its own particular way, depending on which make and model you happen to have chosen and send that signal to the amp. You can set my Voodoo Lab Sparkle Drive to whatever level you want.

Boost pedals (something that makes the signal you send to your amplifier hotter) are fine with a tube front-end but overdrive a solid state input stage and you better like a gnarly spiky signal, cos that's what you're likely to end up with I reckon.
 
#14
bassfishin said:
Nick, I invite you to read this Link Removed You too Jimmy
Click to expand...
With all good wishes, you should do a search here on clipping and DC and read--CAREFULLY--the posts by Bob Lee, Mark Reccord, and billfitzmaurice, for starters. All of these folks have more than enoguh credentials to put your mind at ease. You will find that the idea of equating clipping with damaging DC is nonsense.
 
#15
I'm inclined to go with brotherdoc. If he is throwing more signal into the pedal, the signal gets more of it's signal clipped. I bet if the OP turned his bass volume or the pedal gain down the pedal wouldn't respond the same way. That's just what it sounds like to me based on posts by BassMasta.

Femto, Boost pedals send a boosted signal, which the tube section of an amp; or an od, dist, or fuzz pedal then clip. I am hardly the biggest expert in these parts about this topic, but what I have written I am confident is fact.
 
#16
I thought that's what I said?? It's what I meant. :hiding: I know exactly what a boost pedal does. I shouldn't have mentioned it. We're talking about a distortion pedal here. Sorry.

Well, what I mean is if the distortion pedal in question doesn't have an output volume control, maybe it's output when switched on is hotter than the clean signal from the bass and the input stage of the amp's preamp is clipping.
 
#18
JimmyM said:
It's a load of crap. Amps do not pass DC voltages to the speakers under any circumstances unless they're broken. Period. And they certainly don't do it because of clipping. This guy needs his internet license revoked. Sorry to be the one to break it to you, but coming up with a fancy name and showing a lot of diagrams doesn't make the information presented true.
Click to expand...

You are about half right. It's most likely not going to be the cause of any damage, but it is absolutely possible to get a DC component in an asymmetrically clipped waveform.

Just do the math. Look at the Fourier series of a sin function with one half clipped off, you will find a constant component.
 
#20
Wait a cott'n pick'n minute....!! :eek:

From [Invalid or Expired Link Removed]:
"The LH1000 has a classic 12AX7 Class-A tube front-end design with a solid-state output."

The darn thing's got a tube preamp! That changes things slightly. It should be breaking up reasonably nicely with the tube preamp.

I do heartily apologise - I thought the LH1000 was all solid state.
 

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