As the '70s emerged, germanium-based boosters were still being used, but now for a new rock sound that was much harder and employed greater levels of distortion. Well-known players such as Tony Iommi of Black Sabbath and Brian May of Queen however now were using customized boosters that were designed with fuller ranges of sweep, but also tended to accentuate some of the midrange frequencies. This added a darker complexity and a thicker sound that also added additional overdrive gain when used in front of their amplifiers.

The '70s also brought about the wide adoption of silicon transistors, that replaced early germanium transistors in virtually all music devices. Silicon was superior in its ability to provide a cleaner and stronger audio signal, which was great for preamps, but not so great if you wanted a booster that offered its smooth and unique flavor into the mix!

Into the '80s, the notion and widespread use of "clean-boosting" began and this was often done through the use of overdrive pedals working in reverse. One would set the level control full up and the overdrive to a minimum setting. The result would be more overdrive while retaining the basic characteristics of the amp. Stevie Ray Vaughan employed the famous Ibanez TS-808 Tube Screamer for this effect, but hard rock and heavy metal artists often used some type of overdrive floor box set for boost to run the front end of their Marshall or other amplifier as well to get the "hot-rodded metal" sound. While many musicians chased this high-overdrive/distortion sound by having their amplifiers modified, many of the top pros relied on stock amplifiers and simply kicked in their overdrive boxes set for some clean boost when needed and this was the ticket for some really hot sounds. E.q. boxes were often used for the same effect and overall the e.q. and overdrive boxes worked very well for the desired effect, though some of course were better than others whether offering lower noise or less coloration of the signal. While using an overdrive box in reverse certainly provided a boosted effect, extra coloration did occur from the overdrive boxes and this was certainly just a compromise of the effect itself.

Today, many musicians looking to boost their amplifiers are interested in doing so as transparently as possible. They want the tone they already have, but with the ability to add more to it by overdriving and producing a hotter signal that allows their notes and chords to scream with rich sustain. Keep in mind that the BEST application for any booster is when used in a live or band rehearsal type volume. This is where any good tube amp wants to be played for maximum tone and the Time Machine Boost is designed to work in conjunction with those amps. You won't get the full benefits of working with the Time Machine Boost if it's used strictly as a bedroom-level device. 

Your further questions about applications and recommendations for the Time Machine Boost can be address to david@legendarytones.com.