Early Q2 this year, ALO Audio – a company best known for their portable DAC, amplifiers and upgrade cables, announced their flagship portable DAC/AMP – called the Continental Dual Mono. The ALO Audio Continental Dual Mono is definitely the best portable device they have to date, and today we are going to share to you our review of this amazing audio gear. The ALO CDM (for short) is actually the result of collaboration between the company and Vinnie Rossi of Red Wine Audio. It aims to bring the magic of tube amplifiers into a portable setup. The body of the CDM somehow looks like the ALO Rx we previously reviewed, but a bit larger and with more beef inside. It’s also currently the company’s most expensive portable DAC/AMP retailing at $1,495. Well, is it worth it? Does it sound great? Find out in our review below.
ALO Audio Continental Dual Mono Review
The ALO Audio Continental Dual Mono is currently the best and top of the line portable DAC/Amplifier the company has to offer. While I was reading the features and specifications of the ALO CDM, I think the company carefully designed and spent serious time on R&D with this device. This proves that they want to create something amazing for audiophiles who are into portable setup and tubes.
For starters, the Continental Dual Mono features 6111 vacuum tubes paired with Wolfson’s flagship DAC chip – the WM8741 digital to analog converter. Aside from high resolution PCM formats, the CDM also supports DSD formats up to DSD 2.64.
In terms of power, there are no DC-DC converters for the tubes and there are no transformers as well. A separate linear voltage regulation is used for analog and digital sections, which minimizes the sharing of differing internal voltages across each stage of amplification and the DAC.
The CDM is not purely a tube amplifier, but it is a tube/solid state hybrid amplifier. The combination of the tube and solid state amplification results in low output impedance, tighter bass, better sonic precision, rich midrange, expanded soundstage and better imaging. On top of that, users can also replace the stock tubes, a.k.a tube rolling (which will be discussed later).
ALO Audio decided to go with the Wolfson WM8741 DAC because it has an exceptional signal to noise ratio and extended dynamic range. It also provides low noise, low distortion and superior linearity. The combination of the WM8741 DAC and tube/solid state hybrid amp is what makes this portable device unique from other portable DAC/AMPs.
The ALO CDM has both high and low gain settings, single ended and balanced headphone outputs and line level inputs (aside from the USB input). The CDM is powered with a Panasonic 18650 Li-Ion battery that is combined into a 3-cell pack.
Finally, the Continental Dual Mono is made in USA. Check out more of the CDM’s specifications below and then will proceed and take a closer look at it.
ALO Audio CDM Specifications
- Colors: Silver and Black
- Dimensions: 145mm x 25mm x 82mm / 5.75″ x 1″ x 3.25″
- RMS per channel, both channels driven:
- Single Ended:
80mW into 32 ohms
95mW into 50 ohms
75mW into 150 ohms
60mW into 300 ohms
125mW into 32 ohms
145mW into 50 ohms
110mW into 150 ohms
95mW into 300 ohms
- Single Ended:
- Input impedance SE: 10k
- Input impedance BAL: 50k
- Output impedance SE and BAL: < 1 Ohm
Packaging and Closer Look
The ALO Audio Continental Dual Mono comes in a simple brown box. Very simple and plain actually, with only the name of the product and the company’s logo on top. Opening the box reveals the CDM together with its accessories. As you can see the CDM is cradled on a thick foam protecting it from all sides. There’s also a top cover foam which was not included in the picture above.
The package includes a 110-240V/12.6V/1.5A wall charger with LED indicator, socket adapters, amp straps, a CDM guide and a carrying pouch (which unfortunately is not for the CDM).
Above you see the front and rear view of the ALO CDM. At the front are the following: 3.5mm single ended headphone output; 5 LED sample rate indicator for DSD64 (white), 88.2kHz/96kHz (blue), 176.4kHz/192kHz (green) and 44.1/48kHz (red); a volume potentiometer (also serves as on/off switch); power LED indicator; high and low gain switch and 2.5mm balanced headphone output.
At the rear section of the CDM: 3.5mm fixed 2Vrms analog output signal (straight from DAC); power/charging connection; micro USB digital input; input switch allowing you to choose from digital or analog input sources; a 2.5mm balanced input; and a 3.5mm single ended input. You might be wondering where the battery charging indicator is. There is no indicator for battery charging on the CDM itself, instead the LED indicator is on the wall charger. The LED on the wall charger turns red indicating that it is still recharging the battery, and turns yellow/green when the battery is fully charged.
The Continental Dual Mono measures 5.75″ x 1″ x 3.25″ inches which is still pretty much portable, but definitely not pocket-able. The enclosure is a 4-piece billet aluminum 100% CNC machined. ALO used a special type of glass for the viewing window, it’s a Corning Gorilla glass. The upper half portion where you can see the vacuum tubes is where all most of the components are located. The lower hidden portion is mostly occupied by the 3-cell Li-Ion battery.
There are venting holes on each side of the ALO CDM, as the device gets hot specially during long periods of usage. This is normal actually since the tube/SS hybrid amp section does produce heat. It’s also important that the vent holes are not obstructed or covered to ensure heat is exhausted and fresh air can pass through.
On the next page let’s disassemble the CDM and take a closer look inside.