What’s the difference between the Helios fuzz and Tube Drive pedals?
The drive character of both pedals is completely different as clipping is performed by germanium point contact diodes in the Helios fuzz and by driving tubes into their non-linear region in the Tube Drive. There is some first order low-pass filtering in the Tube Drive to tame the higher order harmonics to give it a smoother, more musical tone. There is also some high frequency premphasis before the first clipping stage. With the Helios there is similar premphasis but no capacitive low-pass filtering. The Tube Drive has an active Baxandall tone control which can reinstate the high-end so can sound crunchy and bight as well as devastatingly smooth and creamy.