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6SN7 + 6DN7 Vacuum Tube Pre-Amplifier

            This is a vacuum tube audio pre-amplifier using 6SN7 + 6DN7 as its active device. A strong bass control effect is the characteristics of 6SN7. Each tube contains 2 active device. In this circuit, 2 of this device had been used in parallel on the input stage. So this amplifier can fully match for any input signal. 6DN7 also contains 2 device inside but with different specification. The little one is for increase voltage gain and the bigger one is for current buffer and output stage. Although I am using a speaker with just a pair of 6 inches bass units ( B&W CDM-1NT ), it still have a gigantic low frequency effect inside a 200 square feet listening room. Because of the disposition of vacuum tube, this circuit also provide warm mid-range and clear high frequency. I am using some silver wire for all of the signal path. It can help for clear treble effect. Metal film resistors and high quality capacitors are also be used for pure sound and reduce thermal noise. Independent regulated power supply for each channels and dual mono design can produce wide sound effect. The feedback components value had been modified for suitable to my style. This circuit was came from a local HiFi magazine for ten years ago. I want to make it for a very long time but cause I am very busy for any other thing. And now, I am so satisfaction that I can turn it on when I was listened to my favorable song.

Appearance 1

Appearance 2

Left Hand Side Amplifier PCB	Right Hand Side Amplifier PCB

Left Hand Side Power Supply PCB	Right Hand Side Power Supply PCB

Pair of Amplifier	Pair of Power Supply

Amplifier in Box	Power Supply in Box

Transformer Unit	Transformer with Shielding Case

EMI Filter	Tone Control

Volume Control	Power Control

Front Panel	Back Panel

6SN7 Vacuum Tube	6DN7 Vacuum Tube

Grounding	Assembly

PCB in the Box

Work with my Audio Space KT88 Power Amplifier

    Schematic Diagram in PDF Format

    Left Hand Side Amplifier PCB Layout in PDF Format

    Right Hand Side Amplifier PCB Layout in PDF Format

    Left Hand Side Power Supply PCB Layout in PDF Format

    Right Hand Side Power Supply PCB Layout in PDF Format

    6SN7 + 6DN7 Vacuum Tube Pre-Amplifier from Magazine in Chinese PDF Format

    6DN7 Data sheet in PDF Format

    6SN7-GT Data sheet in PDF Format