How to make a 5670 tube preamp // DIY HiFi single tube linestage

Scratch building a 5670 / 2C51 / 396A single tube preamp (linestage) for a 2 channel HiFi stereo system. Single amplification stage through a high quality Output Transformer. This will also drive a high impedance headphones. (i.e. AKG K240 600ohm)

A portion of this circuit was inspired from the Valve Magazine Volume 4 Number 5 1998.
The Original article can be found at: https://forum.bottlehead.com/index.php

This topology is known are Parallel Feed and it requires a high quality capacitor and an unique output transformer to function properly.

Specs:
600ohm output
~5-6 db of gain (depending on bias)
1-5670 vacuum tube (1 tube for both channel)
Two (2) 15k Pri - 600ohm Sec output transformer Magnequest B7 (or Edcor XSM 15k-600)
One 250vac ~25-45ma power transformer (i.e. Hammond 261C6)
CRCRC Power Supply

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Preamp Schematic: https://drive.google.com/file/d/1VYthQ8fd00zplAuREBW8OF6KySc4gt77/view?usp=sharing

Basic Layout:
https://drive.google.com/file/d/1xopN3sXNcI9DhpYGQkMyLawYmtaW7Vk2/view?usp=sharing

Parts List: https://drive.google.com/file/d/1KzsnJJDG8y757HWni9hQ5dw1XX9iuE_-/view?usp=sharing

Goldpoint Level Controls: https://www.goldpt.com/

Output transformer: https://edcorusa.com/en-ca/products/xsm-series-2-1-2w-balanced-or-unbalanced-line-matching-transformers?variant=41246090035387

CCS Worksheet: https://drive.google.com/file/d/1GY2-F9jNgyu_LSgFs-WKbbBMdKsrYXAY/view?usp=sharing
For more information regarding Constant Current: diyAudio Tube Constant Current Source Board Project: https://www.diyaudio.com/community/attachments/diyaudio-ccs-beta2_-zip.249066/

Alternate Filament supplies: https://drive.google.com/file/d/1oo-jQPHp9MJe6O-CILmuAxbsJR1Z5ix2/view?usp=sharing

5670 Tube Data Sheet: https://www.tubesandmore.com/sites/default/files/associated_files/5670.pdf

Tubes: https://www.thetubestore.com/jan-ge-5670-2c51
https://www.tubesandmore.com/products/vacuum-tube-5670-2c51w-triode-dual

IU Chassis: https://leeselectronic.com/en/product/10290-enclosure-instrument-case-lg-1983-483x62x204mm.html

WARNING: Tube amplifiers contain very high and potentially lethal voltages!
Drain all filter caps and check voltages before commencing work.

Hakko Solder Station: https://amzn.to/3PvQaD7
Kester Solder: https://amzn.to/3aJKNBI

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