DNA Donald North Sonett Balanced Headphone Amp NOS 6H30 Super tubes, Cardas

DNA Sonett vacuum tube headphone amplifier, balanced model Includes original 6H30 tube (zero hours), JJ GZ34 (brand new) and two 6H30P-DR Supertubes. These sell for $200 a piece at tubestore.com, have thousands of hours of life. One has approx 200 hours, the second is unused. Price includes tubes. Available extras are balanced 10 foot Cardas headphone cables for Sennheiser 650's and 800's; $175 each. Shipping only to 48 CONUS Design features include: • Purist class A single ended triode design featuring the 6H30 Supertube • Transformer loaded output - custom made to DNA's specifications in the USA • No coupling capacitors or cathode followers in the signal path • Selectable output impedance: 120 ohm (IEC setting) or 28 ohm (Low setting) via toggle switch Some headphones are designed to be voltage driven (low amplifier output impedance); others are meant to be current driven (high amplifier output impedance). Depending on the headphone, how you drive them can affect their tonal balance. Many high-end headphones are designed and tuned around the IEC 61938 specification for 120 ohm amplifier output impedance, yet virtually no headphone amplifiers offer this standard output. Using the Sonett, you can now hear your headphones as their designers intended. • Just the right amount of gain: 6dB w/IEC setting; 1dB w/Low setting Many headphone amplifiers have too much gain, thereby restricting the useable range of the volume control to the bottom of the potentiometer where the dual sections are imbalanced, causing one channel to play louder than other. Through the Sonett, you'll have plenty of volume control range with proper channel balancing at any setting. • Flat and extended frequency response with very low distortion • Zero feedback or other error correction trickery Triodes are naturally low distortion when operated into a high impedance load such as a transformer with proper specifications. They do not require feedback to attain low distortion. • 5AR4 tube rectified and choke filtered high voltage power supply The 5AR4 is an indirectly heated rectifier with natural slow-start function for prolonged 6H30 tube life. • Point-to-point hand wired audio circuitry using carefully selected audio-grade components • DC heated for black background - no noise