RO OpATube III 2-Channel Preamp PUBLIC

Richter Original "OpATube III" 2-Channel Guitar Preamp

Richter Original "OpATube III" 2-channel guitar preamp. Largely the same as the first RO OpATube version but with a different tube and an extra volume pot. Here, the 12U7 dual triode is used (not a 12AU7), which is designed to work using a single +12VDC supply-voltage on the plates AND the heaters (originally from a car battery). [Do not use any other tube, including a 12AU7.] Controls Include: Input Level, Ch 1 Enable switch, OA Gain, OA Tone (Bass, Mid-Center, Treble), Fuzz 1 enable switch, Fuzz 1 symmetry switches, Fuzz 1 Depth, OA Level, Ch 2 Enable switch, Tube Drive, Tube Phase switch, Tube Level, and master Blend. Specs for the op-amp section are the same as with the first version, but those for the tube section involve much higher possible maximum gain (up to 52 dBV). Example Supply (not shown): 12V DC 1000 mA Regulated Switching Power Adapter, Product ID: 798. $8.95 each. From the AdaFruit website. https://www.adafruit.com . The tube is available from The Tube Store. https://www.thetubestore.com . Experimental circuitry. Untested design. Thoroughly breadboard test before committing to a soldered build.