300B Amplifier, Input 6SN77, first stage cascode, white follower, Output 300B 5L7 Rectifier, Edcor 25W 5K input, 8 ohm output transformers, Edcor 430v/Dual 5v power transformer, Edcor 1.5 henry power supply input choke.
People that know me are very aware of my love for music. At 8 years old my father and I built a Stereo FM Tuner.
Although tedious, I really enjoyed the challenge of identifying components,
resistor color codes, etc and soldering them together. Unfortunately neither
of our soldering skills were adequate, and the unit needed to be taken in
to a local TV repair shop.
After swapping a couple of resistors, and re-melting countless cold joints,
it came back working perfectly!
Fast forward to now, I still enjoy listening, being fortunate to acquire a pair of
Apogee Duetta Signatures, nearly 30 years ago.
These are fairly demanding load and finding suitable electronics to drive them was a challenge
until I discovered Schiit Audio (yes, it's pronounced like it's spelled).
Duetta Sigs with Schiit Freya S Preamp, Mjolnir Headphone amp, Yggdrasil DAC, Dual Mono Vidar Power amplifiers on floor and Chip
I frequent a Schiit Audio forum where Jason Stoddard, one of the founders,
describes the challenges of starting and running a business, where cost
effective components, can actually be made here in the US. There I met Tom (@Palidan97)
who was gracious enough to loan me his own design Headphone Amplifier, the Incubus.
It had been years since I listened to tubes, and let me tell you, I was very much hooked.
I decided to build my own tube based speaker amp, based on the Western Electric 300B. First made in 1938, this storied device was first used to power telephone exchanges, undersea cables and movie theater sound systems.
The 300B Power Amplifier tube is capable of 7-8 Watts of power output, in a single ended configuration
(A push-Pull configuration will be good for 20 Watts). This may not sound like much, but with the correct speakers,
it can be more than enough. These tubes were considered so reliable, they were put into service powering telephone
exchanges, and under sea communications cable. My particular amp is based on a classic JC Morrison Design, but with
several important changes that result in much better performance.
On the bench, power supply is a choke input, with 1.5 henry inductor. Each side of the stereo amp then has individual supplies