'gain' - is exceeding the thumbs up dangerous?

[Paul S]

I have tried reading through the sticky topics but am frankly still being rather dim about this.

My Trace Elliot head has a 'gain' control on it - whether or not it should be called this I guess is another issue - the usual advice seems to be to turn it up until you start to get the red light coming on then roll it off a touch. For the benefit of numpties like me there is a nice and simple 'thumbs up' sign which I understand.

But what happens if you ignore this and turn it up beyond this? Are we in the territory of causing damage to the circuits? Is it the end of the world as we know it? Do I walk out of the rehearsal room to find a dystopian scene of smoking ruins and beggars in rags? Or is is purely a question of distortion of the sound? In which case I might have a bash.

As you can tell, I don't really grasp much of this - roll on the SE bass bash!

[wotnwhy]

when you hit the red, the signal is clipping. Electronic clipping flattens the peaks of the audio wave. The waves tell the speaker to move (in or out), so when you get a flat peak the speaker is at maximun excursion but not being told to start going back. To keep a speaker out (or in) like this requires a lot of power and produces a lot of heat. So if the clips are to regular or too big, you risk burning out the speaker.

[cheddatom]

Surely clipping the pre-amp is the same as using a distortion pedal.

[johnnylager]

[attachment=64267:clipping_and_you.pdf]

Edited November 18, 2010 by johnnylager

[Ghost_Bass]

In trace gear, clipping is strongly unadvised. Do you have TE's manual for your amp? If not tel me your model and i'll mail it to you. It's very usefull to read this before sart messing with all the knobs and buttons.

Basicly the signal indicators for gain help you to chieve the optimal signal (in every bass you plug) to make the amp run in the best way possible. The trick, like you said, is to (with the volume cutted) play as hard as you use to play and turn the gain knob until the red clipping light turns on, then turn the knob down a notch. This will insure clipping never happens to the amp and it'll last longer withou risk of anything burning inside. If you need more girth turn the valve drive on if your amp has it or use a overdrive pedal.

Beware of what Cheddatom said because he's wrong! The models made to distort the signal have valve pre amps to achieve this effect and even they don't do much distortion! Even if you use an OD pedal you still should adjust the gain knob to keep the pre-amp from clipping!

Having said all this i can assure you from years of experience with trace gear that burning something in a amp or a cab ([b]IF[/b] it is a pre Peavey made or pré Gibson-design, the ones Gibson built with TE's design are still as good as the previous) is almost impossible! Those babies are built like tanks and would take alot more beating than a VW beatle nad keep on going like it had nothing to do with them!

Cheers

Edit: just clarified something that might get confusing

Edited November 18, 2010 by Ghost_Bass

[Ghost_Bass]

If your's like this one then it's exactly like mine. Read page 6 for gain setting

[url="http://www.britishaudioservice.com/inst/12BAND.PDF"]http://www.britishaudioservice.com/inst/12BAND.PDF[/url]

Cheers

[Paul S]

Thanks - yes, that it the exact model. Apparently one of the last UK made ones before it went to Gibson (I guess everyone says this? ) I did print off a copy of the manual when I first got it but wondered if they meant it! Obviously they did. Anyway, no experimentation for me! Thanks.

[cheddatom]

[quote name='Ghost_Bass' post='1028052' date='Nov 18 2010, 03:35 PM']Beware of what Cheddatom said because he's wrong![/quote]

But I can plug my bass into a distortion pedal, turn the gain way up, and plug it straight into a power amp. This way, my distortion pedal is the pre-amp. It doesn't matter if the pedal has a valve in it or not.

I don't mind being wrong, but could you clarify a little more why there's so much difference between a clipping pre-amp and a distortion pedal?

[Ghost_Bass]

[quote]But I can plug my bass into a distortion pedal, turn the gain way up, and plug it straight into a power amp. This way, my distortion pedal is the pre-amp. It doesn't matter if the pedal has a valve in it or not.

I don't mind being wrong, but could you clarify a little more why there's so much difference between a clipping pre-amp and a distortion pedal?[/quote]

Don't know any technical explanation.
I agree you could do that with no problem but remenber a OD pedal is designed to be OD'd and a amp's pre (in most models) is not! So clipping would be safe in pre-amps designed for that function. I see this in most modern amps but TE advises not to clip their amps so they must know excess signal would be harmfull to them.

Maybe that's just why they don't burn up like many others out there!

[BigRedX]

But clipping is clipping and AFAICS the only difference between a circuit that is designed to clip like a fuzz/distortion pedal, and overloading a circuit so that it goes into clipping, is that the waveform tends to 'curve' into the maximum rather than just cutting off square when the end of the headroom is reached. However the long flat duration of the waveform at its maximum which allegedly is doing the damage is the same in both cases...

Edited November 18, 2010 by BigRedX

[clauster]

I'm with Cheddatom on this one. You do not need a valve circuit to achieve clipping distortion (although a lot of people think it sounds nicer), and there's plenty of solid state distortions out there.

There is also no chance of damaging speakers thrugh having too much input gain. Your ouput gain controls how much power is going to your speakers and consequently how much mechanical and heat energy they get and how close they get to maximum excursion.

It's just there to get maximum level of clean sound through the preamp so you get minimum noise and distortion. "Proper" TE stuff dates back to the days when bass had to be clean. Maybe some compression and a touch of chorus, some octave down if you were feeling particularly rakish

If it was dangerous then I'm sure that TE would have built some sort of limiter into the preamp circuit. Or at least have had warnings in the manual in big letters. Mind you, I wouldn't trust that manual - passive instruments usually have one volume and one tone. I never realised the Jazz bass, or the Ricky 4000 series were active basses powered by some magical means

[51m0n]

Clipping is clipping is clipping.

TE suggest you dont because it would sound less lovely (in their opinion).

It wont damage the speakers (we are talking preamp clipping here), it will sound like plop in all probability.

Damaging speakers comes from over excursion or too much heat, clipping a preamp, like clipping in a pedal does neither.

Driving a speaker with too much juice so that it over excurts or overheats does. Not the same thing at all.

Just my 0.02.

And far too late I was with said 0.02!

Edited November 18, 2010 by 51m0n

[Ghost_Bass]

Finnaly somebody with knowledge to enlighten me! One thing i don't understand... when using a pedal, the clipping happening in it afects the amp if it's gain is maintained in safe levels?
My confusion (and probably the proof i'm the one wrong here) is on what realy could damage the circuit or the cab. I believe the long flat duration wave could damage the cab but it's the signal intensity that could harm the pre-ams circuit. Am i right? In this case a over-gained signal could cause damage to the pre but not to the cab if it has enough excursion to handle the input?

edit: read the folowing posts and it's all answered except what could damage the pre-amp

Edited November 18, 2010 by Ghost_Bass

[Mr. Foxen]

The only bit in a cab that can be damaged by amp clipping is the tweeter/crossover, because they see the flat bit as high frequency, and they can't cope with that sort of power level.

[cheddatom]

Can you really blow a pre-amp from driving it too hard? I didn't think so!

[clauster]

[quote name='cheddatom' post='1028175' date='Nov 18 2010, 04:53 PM']Can you really blow a pre-amp from driving it too hard? I didn't think so![/quote]

Nope. If you drive it too hard it just clips.

[Ghost_Bass]

[quote name='clauster' post='1028180' date='Nov 18 2010, 04:55 PM']Nope. If you drive it too hard it just clips.[/quote]

Ok, my bad then!

[MoonBassAlpha]

[quote name='Mr. Foxen' post='1028159' date='Nov 18 2010, 04:41 PM']The only bit in a cab that can be damaged by amp clipping is the tweeter/crossover, because they see the flat bit as high frequency, and they can't cope with that sort of power level.[/quote]

Sorry, you're completely wrong there, you CAN blow the bass driver with clipping. My friend was enjoying playing with feedback into his Trace 1x15 quite loud and it sounded great, for a while....! Burned out voice coil.
Of course the tweeter/xover can also go for a burton, if fitted!