ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review

ddHiFi TC35Pro – EYE2 and MOUNTAIN2 Review

ddHiFi TC35Pro – EYE2 and MOUNTAIN2 Review

The ddHiFi TC35Pro Eye2 and Mountain2 are two small dongle DACs. Equipped with the CS43131 decoding chip and the ES9603Q independent amplifier chip, the TC35Pro E2/M2 presents a significant boost in output power compared to its predecessor. This enhanced power capability is ample for driving a wide range of headsets.

The TC35Pro E2 and TC35Pro M2 showcase a pro-grade shell crafted from aluminum alloy. The titanium color’s wavy surface captures a refined aesthetic. This design reflects the dedication to quality that defines the Pro series.

ddHiFi TC35Pro
EYE2 (left) – MOUNTAIN2 (right)

Despite being marginally larger than the TC35C, the TC35Pro versions are still designed fairly small. Having only the 3.5mm single-ended output, as opposed to the 4.4mm Pentaconn port found in the TC44 series, ddHiFi managed to trim a few more millimeters from the shell. In terms of size, the Mountain2 now measures 28.5 x 17 x 19.4mm, while the Eye2 comes in at 35 x 14 x 12mm (cable excluded). Nonetheless, in daily use, I consistently perceived the latter as smaller, attributed to its slender form.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review

Like all other gear from the brand, these dongle DACs continue to convey an impressively premium feel, a sentiment that is even more pronounced with this new generation. It boasts a clean design, featuring a main aluminum body and a superb braided cable on the Eye2.

ddHiFi being themselves, they also added a small lanyard hole on top of the Mountain2. Once again, ddHiFi checks all the right boxes, presenting a new dongle that is simply exquisite in every aspect.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review
TC35Pro M2 vs TC44Pro

Thick, solid metal, everywhere you can touch and see, and even the geeky lanyard hole of the Mountain2 appears unbreakable, even if there’s an almost-zero chance of me intending to use it for its designated purpose.

The wing-like design, directly inherited from the TC44Pro, might seem strange at first with its dual-side concept, but once plugged into your phone, the flat bottom immediately makes sense allowing you to leave the phone in a downright position, free of any hassle.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review (8)
EYE2 has the TC07S cable attached, which sells for $35.99 alone.

As for the Eye2, it caught my eye right out of the box. With a CNC-milled shell that somewhat resembles a small construct, perfectly beveled angles, impeccable delineation at the center, and a superb cable with a two-tone plug, it currently stands as one of my favorite designs.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review

Last but not least, no screws, no gaps, even upon close inspection, as the brand has ensured every part is tightly sealed.

What’s in the box


Much like the TC44A, the ddHiFi TC35Pro comes with a Cirrus-Logic DAC, the aforementioned CS43131 more precisely, found in plentiful devices nowadays. No dual-dac here, but considering the price point and single-ended output, this is a non-issue.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review

A very popular chip, issued from the MasterHiFi series and advertised as a “low power audio DAC with a high-fidelity headphone amplifier to provide a superior system-level audio performance”.

This chip is more of a SOC than a simple DAC, embedding all kinds of features like an advanced 32-bit oversampled multi-bit modulator with mismatch shaping technology, or an Integrated GND-centered, Class H headphone driver, helping brands to create all-in-one devices, with smaller PCB.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review

SNR is rated at 125dB, THD below 0.0004%, and power output should reach 65mW@32ohm, for each channel with a 32ohms load. Not the best nor the most impressive numbers you’ll see around here, but seeing how small and light the TC44Pro is, that remains impressive.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review

Finally, at the end of the line, ddHiFi chose the ESS ES9603Q chip as the headphone amp. An “industry-leading chip with the highest performance standalone for audiophile-grade portable applications” based on ESS assumption which does sound promising on paper.


  • Model: ddHiFi TC35Pro Eye2/Mountain2
  • Type: DAC/Amp
  • DAC: Cirrus-Logic CS43131
  • AMP: ESS ES9604Q
  • Up to 32bits / 384kHz PCM decoding support + up to DSD256
  • Output Load: 16 – 150 Ohm (adaptive)
  • Output power: 65mW per Channel (32ohm) Balanced
  • SNR: > 125dB
  • THD: < 0.0004%
  • Dynamic Range: > 120dB
  • Auto-impedance sense function
  • Dimensions (excl plug): 35mm x 14mm x 12mm (Eye2) / 28,5 x 17 x 10,4mm (Mountain 2)
  • Weight: 8.5g
  • Price: $75.99  (Eye2) / $65.99 (Moutain2)

 I would like to thank ddHiFi for providing me with the review samples of  EYE2 and MOUNTAIN2.


The TC35Pro is a transparent, clean, and resolving dongle DAC. It does a great job of conveying the sound signatures of the in-ear monitors or headphones you pair it with and does not saturate or color them. Which is exactly what you should expect from a good-quality DAC. It offers a neutral signature.

TC35C 1

While the stage width doesn’t quite match the TC44Pro, when pitted against the TC44A, the Eye2/Mountain2 nearly mirrors it in that aspect, occasionally outshining the TC35C. It also feels more natural, with deeper lows and sharper mids, underscoring the brand’s steady progress, fine-tuning every aspect of its sound signature over each generation of products. 

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review

Lows are fast and powerful. The bass is impressive, even if not as impressive as the TC44Pro. Usually, this is where a small DAC falls short, but this wasn’t the case here, and I could push the volume way higher than I thought. It’s fast and powerful, and with good headphones, you’ll be rewarded with deep, tight, toe-tapping bass. Plus side, it never oversteps on the other frequencies.

Mids have good layering and great spaciousness. The mids blend perfectly with the rest of the spectrum. The soundstage is splendid, sometimes astounding even at the highest level of volume. Compared to the TC35C the mids don’t tend to fall behind the highs and lows, and everything sounds much more even now.

Highs are clean and straight. Compared to the TC35C, the TC35Pro raises the bar and achieves a superb job there, with sharp, harsh-less trebles, and excellent layering. With the right headphones, you’ll get a level of power and accuracy.

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review
Yes, there is a status LED light coming out from the cable of EYE2, like magic.

Pan effects are great, voices are well-articulated, and the TC35Pro gave me clean, authoritative bass, something that I would have not expected for a single CS43131-powered DAC. 

ddHiFi TC35Pro - EYE2 and MOUNTAIN2 Review


The ddHiFi TC35Pro models E2 and M2 are the same dongle DACs in different forms. Personally, I prefer the M2 style. The build quality is superb like in all ddHiFi products for both, performance is much better than many 3.5mm audio outputs on our gears. I wish to see hardware volume controls on the next models though. The competition in the dongle DAC market is getting tougher day by day.