Clipping versus saturation

[MtManiac]

How do you tell which is which? What do you do about either?

I have a Peavey Mark 450, 300 W @ 4 Ohms, and a 4 Ohm Peavey 410T. When I bring the Master up to 6 or 7, and Gain/pre on 3, it starts overdriving, and gets worse the louder I go.

 

[fdeck]

Doesn't that Peavey have the DDT compressor? If you turn that on, and the distortion is still there, then you are clipping the preamp. And if that's the case, you need to turn down the pre gain, or in the extreme case, turn down the output on your bass.

If the compressor makes the distortion go away, then you are clipping the power amp. Your options are to leave the compressor on, and live with the compressed sound (which may not even be particularly objectionable), turn down your overall volume, or get more power.

I suppose another possibility is that you are clipping your speakers. Turning down your bass EQ might help in this case.

 

[billfitzmaurice]

How do you tell which is which? What do you do about either?
.

They're two terms that describe the same thing, but the word 'clipping' sounds nasty, so the euphemistic 'saturation' is substituted. Follow fdecks advice, but I strongly suspect that with the settings listed you're clipping either the power amp or speaker or both. Clipping the pre usually occurs with the gain set high and the master set low.

 

[bongomania]

They're two terms that describe the same thing, but the word 'clipping' sounds nasty, so the euphemistic 'saturation' is substituted.

+1, well put.

 

[MtManiac]

Doesn't that Peavey have the DDT compressor? If you turn that on, and the distortion is still there, then you are clipping the preamp. And if that's the case, you need to turn down the pre gain, or in the extreme case, turn down the output on your bass.

If the compressor makes the distortion go away, then you are clipping the power amp. Your options are to leave the compressor on, and live with the compressed sound (which may not even be particularly objectionable), turn down your overall volume, or get more power.

I suppose another possibility is that you are clipping your speakers. Turning down your bass EQ might help in this case.

This is a big amp (300W at 4Ohm), and I can't say the volume was ear splitting, I was able to comfortably sit in front of it about two feet away and play, although things in the room were shaking. Is it possible that the Squier VM fretless has overly hot pickups? They're passive pickups.

How do I determine whether this is the case without a lot of switching around gear?

 

[bongomania]

AFAIK switching around gear is the best method. I don't know much about that amp, but it sounds like your bass frequencies are boosted too high for it. Try setting the EQ flat. If there's a room rumble or other bad frequency, try using a parametric EQ to nab just the offending frequencies.

 

[MtManiac]

AFAIK switching around gear is the best method. I don't know much about that amp, but it sounds like your bass frequencies are boosted too high for it. Try setting the EQ flat. If there's a room rumble or other bad frequency, try using a parametric EQ to nab just the offending frequencies.

Yeah, it has a very "middy" tone, so I had the bass cranked up for the most part. It has a contour feature also, but that also cranks the highs.

Maybe I'm so used to the little 40W Traynor I've used consistently for the last 20 years that I can't recognize good tone when it hits me over the head, but I know that on the Traynor, I can get lots of nice "mwah" from my fretless, but not so on either the Peavey head or a Yorkville Bass Master that I owned for s hort period of time. The Peavey does have a very punchy tone though, so for some stuff it's bang on.

 

[Hookus]

300 watts really is not that huge. I can would not be surprised that it distorts before becoming ear splitting. With a 300 watt SS amp, you really will need to make good use of the EQ to stand out in a group. The only 300 watt amp I have played that did not follow that rule was the GK 800RB

 

[clanner]

you say that your tone is muddy? boost the mids and highs a bit and bring down the bass, that could be part of it, and don't use the countour switch because they're designed to suck out most mid frequencies and leave with only really lows and really highs.

hope this helps.

 

[anderbass]

Clipping versus saturation
How do you tell which is which?

(To me) clipping is a term I'd only use for solid state amps that have
been pushed past their limits. = bad sound and possible speaker damage.

And "saturation" is a term I'd only use for a tube amp that's been pushed a little
beyond its limits. = A slightly compressed, fuzzy tone and less chance of speaker damage.

What do you do about either?

With a solid state amp I'd turn it down, re-set the eq or use better/bigger speakers,
so the amp wouldn't have to be pushed so hard to get the desired volume and tone.

With a tube amp, I'd call it the sound I usually try to achieve...

 

[bongomania]

(To me) clipping is a term I'd only use for solid state amps that have
been pushed past their limits. = bad sound and possible speaker damage.

And "saturation" is a term I'd only use for a tube amp that's been pushed a little
beyond its limits. = A slightly compressed, fuzzy tone and less chance of speaker damage.

While it's true that people often use the word saturation to describe clipping a signal into tubes, it's still just clipping.

 

[GlennW]

I think of saturation as that nice warm creamy $100,000 tone a guitar amp has just before the output transformer burns up.

 

[billfitzmaurice]

I think of saturation as that nice warm creamy $100,000 tone a guitar amp has just before the output transformer burns up.

The liklihood of damaging an output transformer in that fashion is just as remote as that of damaging a woofer. The first documented case of a super-high gain amp was when Randy Smith cascaded both input channels of a small Fender combo, and gave it to Carlos Santana to use at a recording session. Randy did so as a joke, expecting Santana to go into cardiac arrest when he turned the amp up past two. The actual result can be heard on the 'Abraxis' alblum. That was the start of Mesa-Boogie, and for the first year or so Boogies were in fact re-wired Fenders, using all stock components, and they didn't blow up either transformers or drivers, even though the power amps put out about as close to a square wave as it's possible for an amp to produce.
BTW, about the same time (1970) I cascaded the input channels of a Showman Reverb, but not for the same reason. I was boosting the gain of the amp to make it useable as a PA head with low impedance mics. It never occured to me to try my guitar through it. . But it did make a pretty decent PA head.

 

[GlennW]

You might find this interesting. It goes into cascading channels in old PA amps.

http://www.rru.com/~meo/Guitar/Amps/PA2Guitar/

I only burned up an OT once, don't know the cause. The amp was a 40 year old ebay Silvertone 1484 which had problems. It always made a bunch of noise - I rigged a 3-prong plug for it and it quieted down a lot. I was playing it and it started sounding real good, then it started sounding even better and smelling kind of funny, a minute or so later it sounded better yet and there was a flash of light and a puff of smoke. I have a OT from Bogen CHB 50 that I'll try to put in it one day. I've changed a bunch of electrolytic caps in it - need to finish it up. The Bogen OT has 4, 8, and 16 ohm taps which will be nice.

 

[seanm]

Bill, I would also recommend cutting the bass. But also try boasting the gain and lowering the volume.

 

[62bass]

It sounds to me like you're both driving the speaker past it's limit with the bass boost and the amp too for the same reason. I heard that Peavey cabinet driven by a 1000 watt amp one time in a club. It was very loud but the bassist wasn't able to use any bass boost. But with the rather thinner settings he used it really stood out and was just on the verge of sounding distorted.

Try the settings Fdeck suggested. You may have to live with the less fat sound you'll get by cutting back the bass. Or else upgrade considerably.

 

[billfitzmaurice]

You might find this interesting. It goes into cascading channels in old PA amps.
I only burned up an OT once, don't know the cause. The amp was a 40 year old ebay Silvertone 1484 which had problems. .

Some of the Silvertones were pretty good amps, relabeled Corals, which were Dan Armstrong (DanElectro) creations. I saw Steve Stills using a 68-70 vintage Silvertone 6x10 a couple of years back. The 'Airline' amps sold by Montgomery Ward back then were real pieces of junk, though.

Those Bogen PAs were horrible creations, with gosh awful response and distortion. I did rewire one once with a WE front end, similar to a Fender pre, and it made a tolerably good guitar rig.

 

[A9X]

While it's true that people often use the word saturation to describe clipping a signal into tubes, it's still just clipping.

Technically true but they can have very different harmonic spectra and behaviour in the time domain, hence different sonics.

 

[A9X]

The liklihood of damaging an output transformer in that fashion is just as remote as that of damaging a woofer.

Very true. I've never had an amp on my bench with a failed output transformer from overdriving it, it's always been from a fault condition, or a badly designed component.

 

[Hookus]

Technically true but they can have very different harmonic spectra and behaviour in the time domain, hence different sonics.

Clipping is the effect on the sine wave. This means the tops of the sine waves are clipped off. With solid state, it clips them evenly. With tubes, it compresses the peaks until they are flat, rather than cutting them off. That is why they sound different.

Saturation is what happens to the component, whether be it a transistor or a tube, when an increase in input current fails to produce an increase in current at its output.

Clipping and saturation are two very different things, technically.