Gain Staging and Distortion

One of the best ways to achieve distortion with an electric guitar is through gain stage overload. This is the concept behind the distortion from a Marshall amp with a master volume. The audio input signal is boosted to distortion with the initial gain stage, and high volume is achieved from the amplification of the second gain stage (controlled by the master volume knob). Of course at high volumes you will get some distortion from the second stage, often referred to as output tube distortion, but at low volume all your distortion is coming from the first stage overload. 

Many guitarist are picky about the distortion they want to hear out of their gear which is why there are a myriad of distortion producing boxes on the market from overdrives, to boosters, to fuzzes to what have you. The velocity with which this gear is produced is tremendous. All because you can fine tune your distortion by adding more gain stages to the mix. Some boxes add two or three additional gain stages to the two that are usually available in any decent amp. Lots of guitarist use multiple boxes to get even more gain stages and hence more finely tunable control over their distortion. Sure there are other signal shaping circuits on a lot of these boxes but the most important aspect of achieving good sounding distortion is being able to fine tune your gain staging and the subsequent overloads that can occur between stages.

I've heard it mentioned that Billy Gibbons of ZZ Top uses six expandora distortion boxes in a row for his recording setup. Why would anyone do that if it wasn't from the fine grain control you can get from all those gain stages? If you have more than a few distortion boxes around try hooking up as many as you can and keep the output settings of each box relatively low. After some tweaking you will likely come up with a sound that has extremely long sustain, with highly sensitive and dynamic responsiveness to your picking technique along with a very thick or chunky tone depending on your tweaks and what your going for.

The point is, the more gain stages that you can control and fine tune, the more you can take advantage of the properties of multiple gain staging. Also, the more boxes you use the more careful you have to be in turning them up or you will soon end up sounding like nothing but mud. In the end it is the ability to cleanly and precisely control all your gain stages that will yeild the most benefit to your sound. This is where the quality of the design and build of the hardware you use will really pay off. Don't skimp on gear you use and you will be better off than with the cheapo stuff.

If you have anything to say or add to this go ahead and leave a comment but please remember this is intended to be a pretty basic primer on the subject and a more technical exploration is in order.

Thanks for reading!

Dave At DCXSound

Comments

[garrett]

research swirl, and output tube distortion combo, has to do with the cathode bias of the preamp stage, also low gain preamp stage? early breakup power tubes? that is what I am currently looking for- any suggestions?