Accessing amp gain with which pedal?

[hawkins.bp]

Is the purpose of an "overdrive" pedal to acheive access to the "gain" control of an amplifier without have to turn the knobs on the amplifier? It seems logical to me. From what I've heard from pedal videos on Youtube, the sounds of overdrive pedals are pretty much similar to turning up the "gain" knob on the amp.

[mandroid]

Generic "amp" is too broad .. not covering all the circuit design possibilities used over the decades..

Outboard pedal overdrive Distortion, can be just an attempt to make a overdriven tube sound at a volume that is not at the max.
it adds another plus/minus level control, that you can use with your foot.

but to move the gain pot, on the amp , if you don't turn it manually, then you need a servo-motor set to do that.. in the Amp,
a pedal is not going to do that.

Alternatively, amp needs to be designed to have a effects loop, to run the signal out thru the pedal and back in ..

OR if the signal is as the pedal manufacturer anticipates is matching, [electric guitar] put it in the signal chain before the amp.

[Chip Booth]

The term "gain" is often missued. In layman's terms, it refers basically to volume. But, guitarists use it every day to describe the amount of distortion. For example: "This is a "high gain" amp".

"Real" tube distortion happens when an amp's volume is pushed past the limits of the tubes ability to provide clean power and clipping of the signal occurs. This changes the shape of the waveform, and the resulting "squared" edges create a distorted sound. An amp has multiple tubes and you can overload the inputs of any one of them to create some distortion. You can do this by turning the amp's volume up, which pushes the limits of the later tubes in the chain. You can also overload the input tube with a boosted guitar signal.

Effects pedals such as overdrives or distortions are usually transistor based distortion devices. They use various methods to essentially do the same thing as overdriven tubes: reshape the sound wave into "squared" distortion. There is no need for additional volume gain though, so the output of the pedal can be the same as the guitar's signal. However, a pedal often has additional volume available so you can boost the signal and overdrive the inoput of a tube amp if you choose.

For the most part amps create the best sounding tube distortion at high volume levels. Using an overdrive pedal before the amp allows you create a unique distortion sound of your choosing at any volume level. Also, various methods of creating distorion have distinctly different sounds. You can easily and cost effectively have more than one distortion device to create an array of tonalities and levels of distortion.

Do solid state overdrive pedals sound as good as tube amp distortion? Most people would say no, and I generally agree with that. However, I am a part time pedal builder (http://www.chuckmoose.com/moosetonefx) so I obviously I love pedal effects. I have created overdrives that I think sound nearly as good as vintage tube amps, and some that sound completly different than tube distortion while still being just as pleasing and useful. The truth is that the average musician can't carry around four amplifiers to give you a wide range of tones and distortion. I use great amp and about 12 pedals to give me a huge variety of tonal possilities as well as amazing control of dynamics and other special effects.

[Christian McKee]

In addition to all the above being true, I'd hasten to add that a large number of amps use a footswitch to perform the function you describe, hawkins. My main amp, the Fender Hot Rod is a perfect example. It has (essentially) three channels: clean, drive, more drive; and those channels can be selected via the footswitch. The settings for each channel are controlled by twiddling knobs on the amp, but once those are dialed to where you like them, it's a hands free way to move between three different gain settings on your amp. It's worth noting that not all amp's footswitches work in this way, some of the classics are for engaging or defeating reverb or tremelo, and not all amps have footswitches in the first place.

Confusing enough? Good luck!

Christian