Why is my amp clipping?

[Evil Undead]

Hello! Would appreciate any advice please

Below is a photo of the face of my amp head. It's a Promethean P500 and this shows how I have it set for gigs. The EQ is turned off, and the Vibe function is off, both gain and master volume are straight up (halfway) and the low and high are also in the middle.

I use a Warwick $$ with the preamp on. No effects. I also use an Artec tuner pedal. My cab is a Markbass 102P, 8 ohm.

So, I've noticed that when I play fairly softly, there's no clipping. But when I hit the strings a bit harder for effect in a few songs, the clip light (the one next to the headphone jack with "power" above it) flashes from its usual yellow to red, extremely briefly.

It seems to happen at any volume, whether I turn it right down or right up, and whatever level the gain is set to.

Anyone know why this is happening, and whether it's something I should be concerned about?

Thanks!

[brndn123]

First of all, that's a pretty cool lil' graphic you got there. Congrats on that!

From what it looks like, your amp is set basically flat. Meaning, even though the tone may not be the best, you shouldn't be clipping unless you are really pounding it.

My advice: if you tend to play heavy, buy a compressor and throw it in the fx loop. If you are concerned that it is a tech issue, send it out for repair. Finally, if you have a love/hate relationship with it, off it and buy something better. Good luck sir!

[staindbass]

the clip light next to the headphone is the input clipping. your instrument is putting too much signal into the amp. its distorting the input preamp and the light tells you so. keep the input gain at zero and turn your bass down until the light doesnt flash. (is there a trim pot inside the instrument's control cavity? maybe its up all the way) now you know your not distorting the input. turn up the master to make up the difference. when the cilp light on the right side of the amp starts to light, youve reached its power limit.

[RickenBoogie]

Could just be you're hitting the strings too hard. If it just flashes breifly, don't sweat it. It's when you light it up, and it stays lit a while, you need to worry.

[Rafael]

Actually from the manual staindbass has it backwards: The clip lite near the gain knob on the left is in fact the input clipping LED. The clip lite near the headphone jack is the power section clip LED which according to the ambiguous block diagram seems to show clipping post-EQ at either the master volume control itself or at the power section.

If as you say you get this clip indication even at low volumes I'd guess you have a problem with the amp. However, since I don't own one I cannot tell you if what you are seeing is typical behavior for this amp. I remember years back running a Peavey 400 and the only way to play with it without the clipping lite flashing was to turn the unit off.

[Evil Undead]

Thanks for the replies guys, much appreciated!

Originally Posted by brndn123

First of all, that's a pretty cool lil' graphic you got there. Congrats on that!

From what it looks like, your amp is set basically flat. Meaning, even though the tone may not be the best, you shouldn't be clipping unless you are really pounding it.

My advice: if you tend to play heavy, buy a compressor and throw it in the fx loop. If you are concerned that it is a tech issue, send it out for repair. Finally, if you have a love/hate relationship with it, off it and buy something better. Good luck sir!

I think I just tend to hit the strings too hard on the odd occasion because I can't hear myself that well during a couple of songs (mainly heavier ones) so I assume the audience can't hear me, which they can quite clearly - I asked a few people I know who were sitting FOH, and they could hear every note I played.

I keep the amp completely flat as I do all of my EQ-ing on my bass. Sounds soooooo good that way

Originally Posted by staindbass

the clip light next to the headphone is the input clipping. your instrument is putting too much signal into the amp. its distorting the input preamp and the light tells you so. keep the input gain at zero and turn your bass down until the light doesnt flash. (is there a trim pot inside the instrument's control cavity? maybe its up all the way) now you know your not distorting the input. turn up the master to make up the difference. when the cilp light on the right side of the amp starts to light, youve reached its power limit.

Eeek, I don't know what a trim pot is. This is the inside of the cavity - what would a trim pot look like?

Originally Posted by RickenBoogie

Could just be you're hitting the strings too hard. If it just flashes breifly, don't sweat it. It's when you light it up, and it stays lit a while, you need to worry.

It's never stayed on for more than a fraction of a second. Should be ok?

Originally Posted by Rafael

Actually from the manual staindbass has it backwards: The clip lite near the gain knob on the left is in fact the input clipping LED. The clip lite near the headphone jack is the power section clip LED which according to the ambiguous block diagram seems to show clipping post-EQ at either the master volume control itself or at the power section.

If as you say you get this clip indication even at low volumes I'd guess you have a problem with the amp. However, since I don't own one I cannot tell you if what you are seeing is typical behavior for this amp. I remember years back running a Peavey 400 and the only way to play with it without the clipping lite flashing was to turn the unit off.

I haven't tried it at very low volumes, because I only really use low volume in my apartment, and if I hit the strings hard I'd be in trouble with the guy who lives downstairs haha! but it doesn't do it at low volumes when I play softer. I don't know if that makes any sense...

I thought it was a problem with the amp at first, but I'm just not sure. It is only when I really pound the strings - when I play at a normal power, nothing - stays yellow. Probably just me causing the problem?

There's no distortion or crackling or anything like that.

[IvanMike]

I'd call promethean. If you're not clipping the input at the gain stage but are clipping something post EQ - there is a slight chance that the clip light there is indicating clipping in the EQ itself rather than poweramp clipping. (Active EQ's use some preamplification after all). It's odd that this happens without the EQ engaged, but more than likely the signal always goes to it anyway - just doesn't get sent to the poweramp - in this case you wouldn't hear it as you're not using it.

I think the amp company might be able to figure this one out for you - ask to speak to a tech.

[Evil Undead]

Originally Posted by IvanMike

I'd call promethean. If you're not clipping the input at the gain stage but are clipping something post EQ - there is a slight chance that the clip light there is indicating clipping in the EQ itself rather than poweramp clipping. (Active EQ's use some preamplification after all). It's odd that this happens without the EQ engaged, but more than likely the signal always goes to it anyway - just doesn't get sent to the poweramp - in this case you wouldn't hear it as you're not using it.

I think the amp company might be able to figure this one out for you - ask to speak to a tech.

I don't know what most of that means hehe! But do you think there could be a risk of damage to the amp? Or the cab? Or both?

[billfitzmaurice]

Try turning either the gain or the bass volume control down to stop clipping the input, turn up the master to get adequate volume.

[5StringFool]

Your Promethean only pushes 250 watts with an 8 ohm cab. If you want to get the full 500 watts out of it you'll need another 8 ohm 210, or perhaps get a 4 ohm 410 cab.

If the problem is only occurring during some of your heavier/louder songs my guess would be that you need a little more oomph to get your stage volume up since you're having trouble hearing yourself (but even at 500 watts you'll only get about a 3 db increase in spl)...... or you could try and get the guitarist(s) to turn down some.... good luck with that though.

I'd go for the 4 ohm 410 myself.

[BassmanPaul]

I would think that part of your problem is the single 2x10 you are using. In the real world not a lot of us can get away with such a cabinet. I always use a pair in a vertical stack. This will allow you to be louder with less input signal plus you will have access to the increased power that a 4Ω load will provide.

[Evil Undead]

I agree about the cab. Unfortunately I'm a bit limited with regards to cabs because of my dodgy back - this one's as much as I can handle at the moment so a 410 is out of the question.

I'm looking in to getting another of the 102P cabs but it's going to require a good bit of saving before I can afford it :S

[RickenBoogie]

Good plan. Just save up, and double up. The reward will be more than the sum of the parts.

[Evil Undead]

Thanks for your help

I have another related question...

If I were to get another 210, how would I connect them up? My amp head has one 1/4" output and one speakon. The Markbass 210 that I have has one speakon input and two 1/4" - would I connect one 1/4" to 1/4" as I have been doing, and the other one by speakon (on the amp) to the 1/4" on the cab? Or connect the cabs to each other?

I get confused!

[perogato02]

Connect the 1/4 on your amp to a 1/4 on your first cab and from the other 1/4 from that cab to a 1/4 on your second cab.

[Evil Undead]

Ok. This is in series, is that right?

What is the advantage of doing this rather than one cab 1/4 to 1/4 and the other cab Speakon to 1/4?

[shastaband]

Originally Posted by Evil Undead

Ok. This is in series, is that right?

What is the advantage of doing this rather than one cab 1/4 to 1/4 and the other cab Speakon to 1/4?

NO-THIS IS STILL A PARALLEL CONNECTION!
Both cabs connected to head or one cab connected to head and one cab connected to the first cab are electrically IDENTICAL connections. No sonic advantage one way or the other. (Series wiring would require specially made speaker cables or specially wired amp outputs-IIRC one combo had series wiring for the extension cab output, but that was the rare exception.) 99.9% of the multiple speaker outputs on amps are PARALLEL connections. 99.99% of multiple inputs on speaker cabs are also PARALLEL connections.

[Evil Undead]

Hello all

I tried the amp again today at very low volume, and when I hit the strings hard there is no sign of a red light - just blinks occasionally at the higher volumes, and only when I beat the **** out of the strings!

Is the solution as simple as "don't hit the strings hard"?

[John D]

Originally Posted by Evil Undead

Hello all

I tried the amp again today at very low volume, and when I hit the strings hard there is no sign of a red light - just blinks occasionally at the higher volumes, and only when I beat the **** out of the strings!

Is the solution as simple as "don't hit the strings hard"?

The solution is to stop worrying about it. It's doing what it's supposed to do.

[BurningSkies]

Originally Posted by John D

The solution is to stop worrying about it. It's doing what it's supposed to do.

If you're over-driving from the strings, you should lower you pickups a bit too.