Continental Dual Mono
When 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.
Continental Dual Mono - Manual
This is where we answer some basic questions about the Continental Dual Mono
If you don’t see the question or answer you are looking for you here use our contact form to ask us directly.
PC: What do I need to install for high-resolution audio playback?
DSD Driver Installation
- Install driver package DSD-1.06-(QT).zip
- Download all files, run the “setup.exe” please do not execute the installer located inside the .ZIp file
- Driver supports Windows XP/7/8/8.1
- Foobar 2000
- Install foobar2000 (http://www.foobar2000.org/)
- Install Foo_input_sacd (http://sourceforge.net/projects/sacddecoder/files/ foo_input_sacd/)
- Download foo_out_asio (http://www.foobar2000.org/components/view/foo_out_asio)
- Execute foobar2000
- (1) File -> Preference -> Components -> click “Install…”
- (2) Choose “foo_out_asio”, “foo_input_sacd”
- (3) Click “Apply”
- (4) File -> Preferences -> Playback -> Output -> ASIO -> double click “foo_dsd_asio”
- #1: ASIO Driver: choose “ASIO for USB Device”
- #2: DSD Playback Method: choose “ASIO Native”
- (5) File -> Preference -> Tools -> SACD -> Output Mode: choose “DSD”
- (6) Click “Apply”
- (7) File -> Preferences -> Playback -> Output -> Device: choose “ASIO: foo_dsd_asio”
- (8) Click “Apply”
- (9) Play DSD music to enjoy the sound
- Install JRiver (http://www.jriver.com/download.html)
- Execute JRiver
- (1) Tools-> Options -> Audio -> Audio Device -> choose “ASIO for USB Device [ASIO]”
- (2) Tools-> Options -> Audio -> Settings -> Bitstreaming -> choose “YES (DSD)”
- (3) Click “OK”
- (4) Play DSD music to enjoy the sound
- Driver Installation
- Download and Open CmediaDoPInstall.dmg
- Select file CmediaDoPInstall to begin installation wizard.
- Connect Continental Dual Mono to your Mac and enjoy DSD audio.
- Driver Installation
- Launch Audirvana
- Go to Preferences, Audio System, and under Preferred Audio Device select “Continental Dual Mono”
- Then under Active Audio Device be sure to select DSD over PCM standard 1.0
- Jriver and Foobar settings guide for Mac and PC Download HERE
- My CDM gets very hot, is this normal?
- The CDM uses two 6111 subminiature vacuum tubes that will each generate approx. 2W of heat when running normally. These tubes are the main source of heat you feel from the CDM’s enclosure. In addition to this, some IC’s on the CDM’s circuit board (PCB) will also generate heat. The design of the CDM uses the enclosure as a heat sink that transfers this heat safely away from the PCB and dissipates this heat into the enclosure, where it then radiates to the outside air. It isnormal for the enclosure to operate in the 90 – 130 F (32 – 55 C) range. All of the CDM’s components are rated for operating beyond these temperatures.
- When using its internal dac, the CDM will generate the most amount of heat – as we use linear voltage regulators to feed the DAC stages. Linear regulators are less efficient than switching regulators (DC-DC converters), but offer lower noise and better performance for high end audio applications such as the CDM.
- We recommend that you:
- – Take care when touching the CDM to note that it does get hot to the touch, especially when in DAC mode
- – Do NOT obstruct / cover and vent holes of the enclosure, especially when using the internal CDM dac.
- – Are mindful that the CDM is a tubed-based portable amplifier/dac, and it is normal for tubes to generate heat, as they contain “tube heaters” (filaments) that are required to heat the vacuum inside to tube to function. This, along with the use of linear voltage regulators (above) where chosen for what we believe is the best sound quality in the smallest sized enclosure. Doing so requires the enclosure to get warmer than most portable and transportable amplifiers – especially those that do not use tubes.
- I hear noise when my cell phone is near my CDM, why?
- Cell phones generate large amounts of electromagnetic energy that can cause popping, clicking and other noise in the amplifier. The CDM is a world class state of the art hifi device that uses vacuum tubes. We designed the CDM as a no compromise audiophile solution with the number one priority of the amp being audio performance. We could have implemented measures to have better isolation against cell and TDMA noise but the cost of this is compromise of the audio performance. Therefore we recommend that if you use a cell phone for your source and want to do critical listening please put your cell phone in airport mode. Or if you have cell phones located near the CDM please move them away from the amp.
- When should I recharge my battery?
- The battery used in the CDM is a high quality 3 cell Panasonic NCR18650B. It does not have a memory effect so we recommend you top off the battery charge often rather than letting it run down to 0.
- How do I know when my CDM is fully charged?
- The LED light on the charger will be green.
- What happens when I need to replace my battery?
- The CDM battery is easily replaced and we sell the batteries, no soldering is needed.
- Can I use the DAC with my iPhone and iPad?
- Yes, all you need is a Apple lightning to USB camera adapter cable. You can buy one HERE. or from any Apple store. Connect the Apple camera cable to your iPhone or iPad and the other end to the supplied USB cable, plus the USB cable into your CDM and make sure the selector input switch is toggled in the direction of the USB input on the back of your CDM.
CDM Tube Rolling from ALO Audio on Vimeo.
ESD and safe handling of PCBs http://www.circuitrework.com/guides/2-1.shtml
Windows 10 Driver
New - Windows 10 Driver for Continental Dual Mono
Manual to install Windows 10 Driver
When 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.
Each 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.
At 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 tube-rolling.
Supremely Solid (State)
The 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 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.
Built to be Epic!
When 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.
Each 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.
Linear 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.
Dedicated linear 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
At 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 tube-rolling.
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 impedance.
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.
Microphonics 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 microphonics.
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)
The 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.
The 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 response.
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.
For 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.
Mobile devices 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
The 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.
We 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
The 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.
We included 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
Our 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
Each amplifier is hand assembled and tested in our Portland, Oregon workshop. Each one is carefully inspected to assure you years of satisfied ownership.
“It takes three seconds to tell that ALO went to great lengths to get CDM right, not just good enough. It is a damn near-perfect valve amp/DAC.” “CDM is stable, powerful, wonderfully machined, beautifully branded, and a great match for everything from sensitive earphones to full-size headphones. Its brilliant DAC even nails native DSD decoding, adds spicy contrast, and a thoughtful low-pass filter.”
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