Ceres – Hybrid Tube Amplifier for Raspberry Pi
Ceres is a High-Quality, Hybrid Tube Amplifier, Delivering Fantastic Audiophile Level Sound in a Beautiful and Easy to Use Package. Ceres is designed around a Classic Sound, single tube architecture. The Dual-Triode tube amplifies the incoming signal which is then routed to the Class-A Solid State buffer to provide the proper power to drive a wide variety of headphones. User selectable attenuation and output impedance insure the best sound possible. Ceres can also be used as a line amplifier/buffer between low drive power sources (such as smart phones, music players, LP record players, etc) and your existing stereo system. An important feature of Ceres is the two levels of selectable attenuation. High attenuation is ideal when using Ceres as a line amp or buffer for a smartphone or other low drive power source. Low attenuation insures Ceres delivers the proper level of output voltage (up to 6V RMS) needed for high impedance headphones. Having both options insures Ceres will be fully optimized to your listening environment.
A Raspberry Pi version of Ceres is available with a standard 40-Pin GPIO/I2S interface and TI PCM5102A 24-Bit, 192Khz DAC. Using the wildly popular Raspberry Pi (2 or 3), the 502HTA delivers the full, lush sound of a classic Dual Triode Tube Amp to all your favorite music. Turn your Pi into a wireless audio streaming music server. Place it on your night stand, or at your office desk, or anywhere you listen to your headphones. The selectable Attenuation Switch lets you also use the 502HTA to drive powered bookshelf speakers or your existing stereo system.
Individual Bias adjustments
The left and right halves of the Dual Triode in Ceres have their own individual Bias adjustment, which can be easily set by ear. This allows us to correctly set the bias for each side at the factory, while providing a mechanism for you to adjust to your liking. This is critical as tubes can be several dB’s out of balance between the two halves. Compared to some designs that force a fixed bias level, or use some form of auto bias, this achieves the lowest possible distortion level for each Ceres. This is essential for tube rolling.
High Input Impedance
The input impedance of Ceres is over 10,000 ohms. When driven by low drive power sources such as smartphones, this impedance allows the phone to operate at a much lower level of distortion. In essence, Ceres acts as a power buffer between your smartphone and your favorite headphones.
An important feature of Ceres is the two levels of selectable attenuation. High attenuation gain is ideal when using Ceres as a line amp or buffer for a smartphone or other low drive power source. Low attenuation insures Ceres can provide the proper level of output voltage needed for high impedance headphones. Having both insures Ceres will be fully optimized to your listening environment.
Volume Control and Knob
A high quality, low noise, ALPS Volume Control is used to adjust the signal level into Ceres to let you control the mood. The beautiful machined aluminum knob gives the volume control a solid, smooth feel.
Selectable Output Impedance
A three-position slide switch lets you choose the output impedance of Ceres for an optimal match to your headphone impedance. Selectable between 0, 47 and 100 ohms, this feature insures you can deliver the proper amount of power to virtually almost any headphone, without added distortion due to under or over driving.
Roll Your Own Tubes
Ceres includes a jumper to select between 6.3V and 12V tubes. Combined with the individual bias adjustments, this allows you to swap the factory included tube with virtually any dual triode tube to roll the sound to your preference. And since there is only one tube, rolling is inexpensive and easy.
Class-A Output Stage
While tubes are great at voltage amplification, they do not deliver enough current to meet most headphone requirements. A MOSFET based stage is added to provide this missing current. Operating with the most linear architecture (Class-A), this stage gives Ceres the “punch” to drive even notoriously difficult headphones with ease and clarity.
High Quality Components
Ceres is constructed of high quality components from top tier manufacturers such as Nichicon and Panasonic Audio Capacitors, Alps Volume Control, Bourns Precision Trimpots, C&K Switches and NEC relays. This insures great sound for years to come.
You can find more details about Ceres on Kickstarter. Early bird pledges starting from just $99 and shipping is expected to take place during December 2017.