RO OpATube 2-Channel Preamp PUBLIC

Richter Original "OpATube" 2-Channel Preamp for Guitar

Richter Original "OpATube" 2-channel preamp for electric guitar. Channel 1 uses op-amps chosen for clean operation at all controls settings while Channel 2 uses a pentode designed for a +12VDC supply-voltage on plate AND heater (originally a car battery). The channels can be enabled separately, and both have optional shunt-diode fuzz. Controls Include: Input Level, Ch 1 enable switch, OA Gain, OA Tone (Bass, Mid-Center, Treble), OA Level, Fuzz 1 enable switch, Fuzz 1 symmetry switches, Fuzz 1 Depth, Ch 2 enable switch, Fuzz 2 enable switch, Tube Phase switch, Tube Tone, Tube Level, and master Blend. Frequency Range extends into subsonic and supersonic (< 10 Hz to > 20 kHz) with both channels ON. Maximum Possible Gains: Ch 1 = 33 dBV = Voltage Gain of 44.7. Ch 2 = 39.6 dBV = Voltage Gain of 95. Note that Ch 2 can potentially drown out Ch 1 with all controls at the same settings. This circuit gives the guitarist the choice of solid-state or tube sounds, or both. Solid-state in Ch 1 involves a higher slew-rate, for highlighting pick attack and note definition, while the tube in Ch 2 emphasizes even-order harmonics and gives a more mellow tonality. When enabled simultaneously, both aspects can be blended according to the user's preference. Power-supply not shown. Example Supply: 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 . The IC is available from most electronics supply houses (DigiKey, Mouser, etc.). Note: Untested design. No simulation. Breadboard test before committing to a soldered build. House in a grounded metal enclosure.