Presented preamplifier is one of my line preamplifier with low gain (up to ~10x) designed to be used with ECC82 and 6N30P tubes. First stage is responsible for voltage amplification (VAS) and is based on SRPP topology. Second stage is White cathode follower which isolates VAS from output load and provide less than 100R output impedance. This combination gives us wide frequency response and can easily drive any load even 300R headphones.
Parameters:
- Frequency response: 2Hz – 1.35MHz to 47k load (2.2uF output capacitor)
- Amplification factor: base 10V/V (20dB) without cathode capacitor
- Anode supply: 300V 60mA
- Heater supply: 6,3V 2300mA
- Output impedance: ~50R
Additional features:
- input resistor divider for gain reduction to desired one
- place for bypass capacitor on cathode resistor of SRPP circuit to increase gain
- muting relay at the output
- possibility to change heater style from ECC82 like tubes to ECC88 like tubes in SRPP circuit
MuzgDIY 
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