Billieis hand built to the finest standards using the superb 6922/E88CC dual triode, which in our opinion one of the best noval preamp tubes available. We chose this tube due to its being the perfect preamp tube with an internal screen to ensure a noise-free environment. It gives the listener unparalleled tone quality and listening pleasure.
There are many 6922/E88C's, and equivalent models available, allowing the user to try out many different brands with varying characteristics of this classic preamp tube - also known as tube rolling - which can have a positive effect to the overall sound of this headphone amp.
Billie is shipped with a pair of factory new and matched gold pin 6922/E88CC's, or we can use client-supplied tubes. Please note that it will take time for these factory new 6922/E88CC's to settle in and mellow, typically requiring about 50-100hrs.
Billie uses a pair of E88CC dual triodes in a single stage amp circuit with a solid state CCS (Constant Current Source). This is a simple yet amazing sounding circuit that uses just a handful of components and has no feedback or coupling capacitors. We do not believe in over designing ANY circuit just for the heck of it - keep it simple and allow the tubes do their jobs! The output is fed into a pair of outstanding Lundahl LL2765 headphone amp output transformers.
Billie also offers the option to select two levels of headphone impedances, hi @ 600 OHMS or low @ 300 OHMS. This choice of impedances will cover pretty much all higher end headphones on the market today.
Standard is unbalanced RCA inputs and unbalanced 1/4" jack output.
Optional are balanced in and outputs. The unbalanced to balanced and vice versa circuits are handled by the excellent Texas Instruments INA134 and DRV134 chips.
Whilst the main amplification circuit of Billie is quite straightforward, it is quite another story for Billie's power supply. In order to ensure virtually no background noise and a hum-free headphone amplifier, the power supply is a very advanced design. To that end, it is all solid state with a regulated high voltage B+ and regulated DC filament supplies, both being extremely stable and clean. The result is a dead quiet headphone amplifier that will provide many hours of listening pleasure.
Only high quality components are used in the construction of Billie. Low noise, +/-1% variation Vishay CMF series metal film resistors are used throughout the signal circuit, as are high quality Panasonic metal oxide resistors in the power supply circuit. Nichicon electrolytic capacitors are used in the all-important power supply. A pair of first class Lundahl LL2765 output transformers will give unparalleled clarity and listening pleasure.
The printed circuit board is designed in house and manufactured to FR4-TG standards. It is double layer with full ground planes on both sides to ensure complete screening of the circuits. RCA and XLR sockets are high quality Nutrik.
Tubes are a factory new, quad set of matched gold pin 6922/E88CC's.
Amplifier output - 125mW
Frequency response is +/- 0.5dB 20Hz to 35KHz
Signal to noise -86dB
Chassis size: 8.5"W x 12"D x 8"H