In the 90s there was a recollection. Grunge killed the dreams of the hairspray-metal bands and thus, also of the effect-industry. For cost reasons and also as a commercially statement many guitarists bought second hand pedals and were satisfied with two or three of them. The previous polished sound became rougher.
This supported a new kind of effect-industry: the first boutique-pedal-manufacturers repaired old pedals, modified them or produced clones of rare pedals. One of the first boutique-manufacturers was Analogman. He started to modify the Ibanez Tubescreamer and became a legend with his interpretation of the Fuzz Face, the Ross compressor and the EHX Chorus.
Fulltone also produced clones of famous pedals for the moment. These included the Fuzz Face, the Tone Bender and the Octave Fuzz. Later he added his own creations which were based on already known circuits.
And furthermore Electro Harmonix , at those days named Sovtek (they had to file insolvency because of the low demand for pedals in the 80s), started to produce pedals in the 90s. The russian Big Muff is one of the most wanted pedals.
Keeley Electronics became famous by their copies of the Ross compressor and their Tubscreamer-modifications.
All of the boutique- pedals included some kind of improvement, like the use of true-bypass-switchers instead of a buffered bypass-switching. Partially almost rare components were used, like for example certain germanium- transistors or clipping-diodes. The parts have been selected according to measured values, so the sound of a pedal could be tuned in a specific way. This was an important development which ennobled the sound and minimized besides-noise.
Since those days every boutique-manufacturer created his own interpretation of the legendary Tubescreamer. Either it could produce more gain or the new version got more bass than the original.
Boutique vs DIY
These days the boutique-pedal-sector is vanishing in a certain way. In the internet one can buy “boutique”-kits with an individual paintwork, sometimes even for its cost price. But the ones who have ever played a Fuzz Face -clone with matched transistors and adjusted bias (by adjusting the resistors), know that although a Fuzz Face is made of 10 parts, these have to be adjusted in a very special way.