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ALO Audio The International+ Optical Edition Review – Portable DAC with Amplifier

Early this year, ALO Audio released their latest portable DAC with headphone amplifier – The International+ Optical Edition, in addition to their existing lineup. The International+ Optical Edition is somewhat similar to its predecessor, The International+, but it uses a 32bit Sabre32 ES9018K2M DAC chip instead of the 24-bit Cirrus Logic CS4398 DAC chip on The International+. Aside from the DAC chip, the Optical Edition has now an optical input on the rear portion and is using mini USB ports instead of micro USB ports. I haven’t tried its predecessors, so I am not going to compare the Optical Edition with the non-optical edition in this review. But this review will focus more on The International+ Optical Edition itself. Before we proceed with the review, I’d like to thank ALO Audio for providing the sample for the purpose of this review.

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ALO Audio The International+ Optical Edition Review

Last February, ALO Audio released a new variation of one of the company’s popular portable DAC with amplifier The International+; they call it The International+ Optical Edition. Obviously based on the name alone you already have an idea why they call it the “Optical Edition”. It features a 3.5mm Optical input via a TOSLINK cable. This would be a good portable DAC/AMP specially if your source can output via optical connection, like a desktop PC or some DAPs like the or Astell&Kern AK120 II or the new AK240 Stainless Steel. Some of you may already know the benefits of optical connection vs. a 3.5mm or USB connection. If not, a few searches from Google should provide you with a good answer.

ALO Audio also used a new processor in the heart of The International+ Optical edition. It now features a Sabre32 ES9018K2M DAC chip, while its predecessor (The International+) uses a Cirrus Logic CS4398 DAC. Here’s a little information about the said DAC Chip:

“The ES9018K2M SABRE³² Reference DAC is a high-performance 32-bit, 2-channel audio D/A converter targeted for audiophile-grade portable applications such as mobile phones and digital music players, consumer applications such as Blu-ray players, audio pre-amplifiers and A/V receivers, as well as professional applications such as recording systems, mixer consoles and digital audio workstations.

Using the critically acclaimed ESS patented 32-bit Hyperstream™ DAC architecture and Time Domain Jitter Eliminator, the ES9018K2M SABRE³² Reference DAC delivers a DNR of up to 127dB and THD+N of -120dB, a performance level that will satisfy the most demanding audio enthusiasts.

The ES9018K2M SABRE³² Reference DAC’s 32-bit Hyperstream™ architecture can handle up to 32-bit PCM data via I2S, 384kHz input sampling rates and mono mode for highest performance applications. Both synchronous and ASRC (asynchronous sample rate conversion) modes are supported.”

I’ll discuss more of The International+ Optical Edition’s features as we take a closer look on the product itself. You can also check out some of its technical specifications below.

The International+ Optical Edition Specifications

Frequency Response+ / - 1dB - 5Hz - 160 kHz (tested at 300 ohm)
Maximum Output10 V Peak to Peak
THD+N0.001% @ f = 1 kHz
Input Impedance50k Ω
Output Impedance<1 Ω
RMS power per channelboth channels driven
Output Power - Balanced80 mW into 32 ohms
105 mW into 50 ohms
210 mW into 300 ohms
80 mW into 600 ohms
Output Power - Unbalanced105 mW into 32 ohms
130 mW into 50 ohms
52 mW into 300 ohms
26 mW into 600 ohms
Battery3400 mAh Lithium-Ion (Sanyo UR18500F)
Battery Play TimeMin. 15 hours (Amplifier) / Min. 7 hours (Amplifier + DAC)
Battery Recharge Time3 hours

Packaging and Closer Look

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The packaging includes pretty much everything you need. The box includes a sturdy carrying pouch, Amp staps, right angle optical cable, straight optical cable, USB-A to miniUSB cable, a 110-240W wall charger and a reading material as well as a discount coupon. I’m not sure if the discount coupon is a regular or not, but it’s good that the company offers such discount. By the way, ALO Audio has opened their Warehouse Deals offering discounts to some of their inventory. You may view their latest deals here

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The carrying pouch can house everything and not just the DAC/AMP itself. Out of the box, The International+ Optical Edition is cradled inside its pouch, secured with rubber pads and an elastic strap. There is a flip cover that protects the device.

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The device measures 2.84″ x 3.33″ x .94″ and weighs around 8 oz. It feels a little bit heavy but very sturdy and solid. The aluminum casing has a glossy black finish and the paint job is really good. Unlike its predecessor, The International+, the Optical Edition only comes in one color.

In the front section you see a 3.5mm mini-jack output for your headphone or IEM; next is the mini balanced output; a 3.5mm mini-jack input, an output gain switch and a volume knob. There is a tiny orange/yellow LED power indicator located in between the gain switch and the volume knob. On the rear section, you see the optical input port, a mini USB charging port and a mini USB data input port. There’s also a tiny charging LED indicator right beside the mini USB charging port.

It may be a little difficult to set the gain switch specially if you have larger fingers and/or your 3.5mm input jack is larger. I would suggest that you set the gain switch before plugging the interconnect, if you are going to use the 3.5mm input jack. In my experience the Low and Mid gain settings are usually for IEMs and earphones, while Mid to High are usually for on-ear and over ear headphones.

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It’s very easy to open the ALO International+ Optical Edition. You only need to remove four small screws located on the rear portion. Above you see the top and bottom portion of the device’s main board. There are actually two PCBs inside the device; both are bind with a plastic transparent wrap. If I am not mistaken, the first PCB layer is for the DAC section, while the other one is for the AMP section. The large black thing you see in the middle is the 3400 mAh Lithium-Ion rechargeable battery. According to the company, ALO Audio is using a Sanyo UR18500F battery which is rated to last up to 7 hours if both the amplifier and DAC section is used. It requires at least 3 hours to fully charge the battery.

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As you can see from the angled shots above, both the 3.5mm input and output jack are gold plated. Meanwhile, at the rear section only the two mini USB ports are visible. The optical portion is hidden in between the two layers of PCB. Well, there is not much to see from the inside so let go ahead and put The International+ Optical Edition to the test.

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Peter Paul
Peter is a PC enthusiast and avid gamer with several years of hands-on experience in testing and reviewing PC components, audio equipment, and various tech devices. He offers a genuine, no-nonsense perspective, helping consumers make informed choices in the ever-changing world of technology.

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