The Hydra Treble Booster is an adaptation of the Catalinbread Naga Viper, itself based on the Dallas Rangemaster, but with an NPN silicon transistor instead of the PNP germanium of the original.
Although it’s referred to as a treble booster, there’s nothing clean about it. It’s very much in the overdrive territory, not quite full-on fuzz but in the same tradition.
The Naga Viper adds versatility to the one-knob Rangemaster design by including an input capacitor blend (labeled “Range”) to go between treble boost and full-frequency boost. Fully clockwise is the same as the stock Rangemaster.
There is also an added gain/saturation control (labeled “Heat”) to allow the transistor gain to be dialed back from the fixed full-gain setting of the original. As with the Range control, when set fully clockwise, it’s the same setup as the stock Rangemaster.
Despite the two additions, it remains a very low parts-count circuit and great for beginners chasing some of the classic sounds of the 1960s.
The Hydra project is a direct adaptation of the Naga Viper with no modifications or changes.