I have played guitar for quite a few years now, but I never much bothered to get into the technical side of it. I have an amp setting that I’m used to, so I just stick with it. So perhaps it is a bit late to ask these questions, but:
What exactly is “gain?”
What is the difference between “high gain” and “low gain?”
What is “trim?”
What is the difference between the “high” and “low” input jacks found on many amplifiers?
Can the above things be explained without using lots of technical terms? I mean, really dumb it down for me here. I barely even understand what a Herz is. That’s another good question.
“Gain” controls the amplitude of the signal. If the amplitude is higher than the input threshold (“volume” knob) the guitar will distort, allowing the user to rock accordingly.
Hmm. Are “high gain” and “low gain” two different knobs on your amp?
Trim. Ya got me. I’ll try to look it up.
hertz is a unit of frequency. Amplifiers can be classified by the sinal frequency range they’re designed to handle.
As a physics major, I can handle a couple of these, but the rest will have to wait until I become a rock goddess.
Gain is the amount of amplification that the amp is doing, like a voltage change. This isn’t quite the same as volume though, for reasons that I’m not entirely clear on. The only amps I’ve ever dealt with have been in physics labs.
Maybe just a high vs low voltage change?
A Hertz is just a unit of frequency equivalent to 1/seconds. So a tone with a frequency of 770 hz has 770 wave peaks per second (since sound is just a wave, after all). Let me know if you want this cranked down or up more.
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How much louder the signal will get after passing through the amp. Sorta like the amount of magnification on a zoom lens.
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On an amp, usualy the end result is that it will be louder if plugged into the high gain jack. Some guitars are hotter than others, and you get a differant sound depending out which you use. For more technically inclined, look here http://www.torresengineering.com/latvinguitar.html
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Generally, its a way to adjust the input signal so that it doesnt overdrive the preamp. Sort of a volume control
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depends on the amp, but often its for lower freq. stuff like bass.
However, now I’m really confused. What, then, is the difference between volume and gain? And if “trim” is also “kind of like a volume control,” then how is it different from the other two?
Gain vs Volume. Volume, obviously controls the volume while gain controls how much signal is sent to the amp circuts. Basically, IIRC, when you turn up the gain you are sending so much signal to the amplifer circuts that the amplifer cannot really deal with it and you end up with the signal being distorted. Gain allows angry young men and women to make alot of noise and piss off parents worldwide. Turning up the gain probably affects the volume somewhat but it is probably a really small amount.
Trim: I’ve never heard of this before (and I’ve been playing for 20 years) but I’ll take a guess and bet that it is a compressor-limiter type of control. If my guess is correct then trim limits the amount of input coming straight from the guitar.
Hot guitars: This relates to pickups and different guitar bodies. Hot guitars pickup more signal from the strings. You can play with this on your own guitar pretty easily by raising or lowering your pickups. The closer to the strings the hotter the pickups are going to be. Also, the pickups, the body style of the guitar and the wood it is made out of affect how hot a guitar is.
Everyone is describing gain as it relates to volume. Could you maybe start out by defining “volume” instead? I realize it is how loud or soft the sound is, but then how does that differ from how much signal is sent. What specifically does the volume knob control?
Ok, this is how it works. Volume is created by the speakers. It’s a pressure thing, the more air a speaker moves creates more sound pressure which is louder. Now, the amplifier controls how much current is sent to the speakers which you control with the volume knob. More current equals more speaker movement.
Now, about signal. Let’s start at the begining. When you hit a string on your guitar the string vibrates. The vibrations of the string cause the magnets in the pickups to vibrate. The magnets in the pickups are surrounded by copper coiling (hence the name single coil pickup, humbuckers are two magnets and coils in one that ‘buck the hum’ single coil pickups have. Hence the name humbuckers). When you vibrate a magnet surrounded by copper it creates current in the copper. That current is sent down the cord to the amp. That is the original signal coming from your guitar. The signal then goes into your amp. Here things get a little tricky. The signal then goes to the preamp. The preamp are the circuts that allow you to shape the tone. The treble, bass, gain and reverb controls are part of the preamp (BTW, I might have this somewhat wrong as I always hated Electrical Engineering. Someone correct me if I am mistaken). Anyway, the preamp takes the signal from your guitar and modifies it. The modified signal is then sent to the amplifier which just takes the signal and, well, amplifies it by controling how much current is sent to the speakers.
In other words the volume knob-amplifier simply takes the signal handed to it by other things and then makes the signal louder.
Different amp makers use different terms (unless the term is scientifically based, like watts or something) so there is no set definition.
Slee is on the right track - gain is how much you are overdriving the amp, volume is the actual loudness coming out of the speaker. High gain but low volume would sound very distorted but you might be able to play at night in your dorm; low gain but high volume would sound clean be very loud, depending on the power of your amp.
High Gain vs. Low Gain - specific to your amp, but probably the level of distortion available. If your amp has two channels, there is typically a Rhythm channel - i.e., the signal can only be distorted so much - mostly for clean work to hard rock levels of distortion. the Lead channel’s gain typically starts out higher and gets even more gnarly as you increase gain levels. Why? Well, for lead work rockers use gain (or overdrive, if you will) to increase the sustain (how long the note sounds) of single notes as they play leads.
Trim - specific to your amp - could be a tone link control cutting highs - not much different that a regulat tone. Or it could be a form of compression - circuitry that limits the dynamics of the amp so that the difference in loudness between a soft pluck or a Pete Townshend windmill on the strings isn’t nearly as dramatic. For someone like Eddie Van Halen, who does a technique called tapping where he taps the fret of a string 12 frets above where he is making a chord on the neck to emphasize the harmonic more than the actual string sound (this technique sounds cool but is very very soft and would get lost in the middle of a rock song if kept at normal volume) compression ensures that his softer sounds get a boost to even them out volume-wise. You need to play with the control at 0 and at 10 and listen for differences in tone or volume dynamics, etc. Or go to rec.music.maker.guitar in Google groups and state the name of your amp and ask what trim is - some tech geek will know.
Hertz - the freqency of sound. Humans typically can hear sounds between 400 - 4,000 Hertz or so. However most audio systems are expected to deliver between 0 - 20,000 Hertz because a lot of what humans like in a tone is harmonics above and below the normal range.
Ok, GAIN, does not mean distortion. Distorion is a result of more gain than the amp can handle. In guitar amps, this is desirable, but gain does not mean distortion, too much gain(or enough gain, depending on how you look at it) results in distortion.
Trim is usually found on mixers, its to fine tune the input level so that the signal doesnt distort(or does, again, depending on what you are going after). Compression/limiting is a totally differant thing (and is way way overused in todays music, IMHO…but thats a differant topic altogeather).
Hot means a higher voltage coming out of the pickups, which in turn will overdrive the amp easier.
It differs in terminology from amp to amp, but for the most part, the signal comes in to the amp from the guitar. This signal is very low level. The trim control fine tunes the level of this signal, how loud it is to the amp. Then the gain control tells the amp how much louder to make the signal. the volume control tells the amp how loud you want the signal to be when it goes to the speakers. The higher the voltage, the farther out the speaker moves when it gets the signal, so the louder it sounds when it gets to your ear, and the hearing loss you get and and the frequency of the men in blue showing up at your door is proportional to that.
So why do we have so many knobs that seem to do the same thing? Most amps sound better when they are really working hard, and when they have a louder signal going in. By changeing the level of the signal at various stages of the amplification, you get differant sounds.
For instance, a Guitar player I wasrecording in my studio the other day plays through a 64 blonde fender bassman that has no master volume control…All we had was gain to work with. IT sounded great, but it was unbelievalbly loud, especially in my small live room. Luckily, I have an isolation/vocal booth that is
pretty sound proof, so we stuck the cabinet in there, sealed it off, and recorded with him listening to the feed from the mics through my monitors, but if he had a master volume control, like your talking about, we could have turned it down a bit, and still got that nice tube distortion. I try and talk gtr players I record into using my Pod Pro(amp sim) for this reason. In fact, my own gtr player in my band, and my bass player both play through pods. NOw if I could just get my drummer to switch to v drums, things would be great.
People use the term “gain” to mean different things. In a tube amp with a master volume control, you can overdrive a pre amp tube to get distortion. “Gain” in this instance descibes the amount of signal that’s going to that pre amp tube. The more gain, the more overdrive. Since its a pre amp tube it doesn’t much effect the overall volume.
The term is used similarly on overdrive and distortion pedals. You got your volume knob, your tone knob and your gain knob. The gain knob would control the amount of overdrive or distortion.
High gain amps are the modern Mesa / Boogie type amps that have lots of overdrive and can have several gain stages (i.e. more than one pre amp tube that can be overdriven). You want to use this for Heavy Metal, etc. Low gain would be only a little bit of overdrive.
Now, what’s the difference between overdrive and distortion you ask?
