Built to be Epic!
we started working on our newest generation Continental wanted to do
something amazing. We examined each element of the amplifier – 6111
tubes, Wolfson DAC, Power Supply, Volume Potentiometer, Battery,
Capacitors – to find the best sounding component. As we put them all
together we ended up with The Continental Dual Mono.
stage of the CDM has its own dedicated linear voltage regulator. This
means the internal voltage of each stage is independent. This minimizes
the sharing of differing internal voltages across each stage of
amplification and the digital to analog converter.
voltage regulators are used because they produce a cleaner voltage rail
than typical switching regulators. Because they do not use a switching
waveform, linear regulators have lower output noise. Lower output
noise is better for clean amplification. And in high fidelity
amplification it is critical.
voltage regulators to each stage of amplification provides optimally
clean power. Less crosstalk between the stages and better isolation of
the analog and digital sections.
The Touch of Tubes
the center of The Continental Dual Mono are a pair of New-Old Stock
6111 Vacuum Tubes. Each tube is individually soldered to a custom PCB.
This provides mechanical isolation of each tube, insulating them from
unwanted microphonics. It also provides a quick and easy solution for
Directly following the volume
potentiometer, the dual 6111 vacuum tubes provide the current gain (ie
tube “buffer”) to the amplification. This provides a clean, strong and
dynamic signal to the headphone output stage at a lower output
Running in Class A, the Dual Mono
implementation of the vacuum tubes provides improved stereo separation
and an expanded soundstage. This is because of lower levels of
crosstalk achieved between Right and Left channels. The tubes are
auto-biased so there is no need for any time consuming manual biasing.
are a unique challenge when introducing vacuum tubes to a portable
amplifier. The design of the tube circuit in The Continental Dual Mono
minimizes the inherent microphonic tendencies of the tubes. Utilizing
the tubes as a buffer, handling the current gain and not the voltage
gain reduces microphonics. Mechanical isolation of each tube and the
component layout of the PCB further assist eliminating any distracting
While the tubes are user replaceable,
the vacuum tubes as implemented can easily be expected to provide 5+
years of reliable operation.
Supremely Solid (State)
Continental Dual Mono is a “tube/SS hybrid” amplifier. It delivers the
low output impedance, tight bass and sonic precision of a solid-stage
amp, but with the added midrange richness, expanded soundstage and
spaciousness of a tube amp.
The Class AB solid-state
output stage is designed laid out with short path lengths and a low part
count. Only the highest quality components are used in The Continental
Dual Mono. The voltage regulators, decoupling capacitors and resistors
all have tight specifications. Rated to operate at wider temperature
ranges and for extended cycle life.
Wolfson WM8741 DAC chip occupies the heart of The Continental Dual
Mono’s digital section. We selected this chip after extensive
examination of all available reference DAC chips. The WM8741 has
exceptional signal to noise ratio and extended dynamic range. It also
provides low noise, low distortion and superior linearity. The Wolfson
provides high resolution DSD and PCM playback and offers musically
compelling digital filters.
WM8741’s minimal phase
digital filter is more natural sounding because it has no ‘pre-ringing’
of its impulse response. Just as a piano doesn’t produce sound before a
key is pressed, the minimal phase filter doesn’t ‘pre-ring’ its impulse
The power feed to the digital section is
turned OFF when the USB cable is unplugged. When the DAC is active, the
internal Li-Ion battery and linear voltage regulators provide the
power. The noisy 5V rail from the USB is not used for any part of the
power. This means less grain to the sound and no digital harshness.
lowest amounts of jitter and cleanest digital to analog conversion we
used a high quality clock IC in The Continental Dual Mono. For both PC
and MAC computers, PCM 16/24 bit – with these sample rates (kHz) of
44.1, 48, 88.2, 96, 176.4, 192, as well as DSD64 are all supported.
MACs require the driver provided for DSD playback. PCs require a
driver for both PCM and DSD playback.
also play well with The Continental Dual Mono. Most Android devices can
pair with the DAC using a micro USB OTG cable and the ALSA driver.
Please note: Apple iDevices can in general
pair with the DAC using an Apple Camera Connection Kit and micro-USB to
USB-A cable. iPads work consistently. iPhones with iOS 9.02 appear to
work well. iPhones with iOS 9.1+ have mixed results, depending on
track, music App, etc.
The front panel lights provide
you with quick access to the DAC’s sample rate. Red = 44.1 / 48kHz,
Green = 88.2 / 96kHz, Blue = 176.4 / 192kHz, White = DSD64
Big Beautiful Battery
Panasonic 18650 batteries are combined into a 3 cell pack to provide
clean, reliable power to The Continental Dual Mono. The 3-cells are in
series to deliver the voltage the tubes demand.
selected the this battery because it has a high cycle life,
approximately 1000 cycles. It also provides short circuit and
overcharge protection. It is also safely user replaceable. So when you
reach the end of the batteries life, you can swap in a new one and keep
the music going.
Using a high quality battery to
power The Continental Dual Mono makes the music come alive. Beyond the
low noise floor you’ll discover tight controlled bass, natural midrange
and a grain-free extended top-end. The clean power is immediately
appreciable in the dynamic sound from the amplifier.
Audio Line Out
Continental Dual Mono has a true “Line Out” on the rear panel. This is
a fixed 2Vrms analog output signal. This signal is from the output of
the DAC’s analog output stage. It is tapped before going through the
volume control or headphone output stage.
this feature to showcase this exceptional DAC. It is intended to drive
a preamp, integrated amp, another headphone amp, such as our Studio Six
headphone amplifier. Please note that the Line Out is not intended to
drive headphones directly, but instead offers you flexibility in using
the DAC with your other components.
Awesome by Design
new enclosure design is inspired by our daily use of our products.
Machined markings resist wear and the minimal icons keep you focused on
the music. The Gorilla Glass window lets the tubes shine without
exposing them to the elements. Expanded vents running along the sides
of the CNC’d aluminum enclosure keep The Continental Dual Mono breathing
as the tubes heat the interior.
Designed and Assembled in the USA
amplifier is hand assembled and tested in our Portland, Oregon
workshop. Each one is carefully inspected to assure you years of