It’s no secret that you can increase the size of your compressor by adding another extension tube, but with so many types to choose from there can be some confusion over what kind of compressor gain is best for your particular application. The most common compressor gain, found in many of today’s larger compressors, is the bipolar unit, and these tubes are in fact two equal amps of pressure applied at the same time. The reason they’re called “bipolar” is because they act as a single unit, unlike the more common single mono tube. Another common choice, the low pass filter, moves the sound around within the soundboard of the amplifier before reaching the ears, again acting as a single amp of pressure applied to a different input.
More commonly used for special purpose applications or as a frequency-shifting low pass filter, or even a regular hum buster, are condenser and solid state amplifiers. An electrostatic tube amplifier, or ETA, has one or more large coils of wire placed around a graphite core. These tend to have a higher distortion and frequency response than others, but are less expensive, being made from cheaper materials like copper or aluminum. Depending on your application, it may be a good idea to keep costs down, if you can, and look for a component to cut costs that fits your application needs better.
For other amplifier options, the first place to look would be online for some more information on amplifier gain. There are an incredible number of online resources that can help you figure out which units would work best for your application. Regardless of what type of equipment you have, or even if you’re trying to find new equipment for your shop, make sure you do your homework before you buy! There’s nothing worse than buying a piece of equipment, only to realize that it doesn’t match your requirements for many years after you buy it.