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TANCHJIM OLA II Hybrid IEMs Review

A hybrid in-ear monitor pairing a 10mm DMT5 dynamic driver with a Pure Hi balanced armature, listed from $75.20 with 3.5mm, 4.4mm or Type-C terminations. The Type-C version adds DSP and an 8-band PEQ, per the page.

3.4Editorial rating: 3.4 out of 5Editorial rating · research-basedUpdated October 28, 2026
From $75.20Price checked October 28, 2026
Check price at HiFiGO

Our verdict

This hybrid IEM from $75.20 fits buyers who want a choice of 3.5mm, 4.4mm or a Type-C version with DSP and an 8-band PEQ. Look elsewhere if you need impedance or sensitivity figures, a microphone with the 4.4mm version or EQ support beyond the Android app the page names. The main caveat is that the page text carries no specification list, so every figure is the store's own.

Best for
Buyers who want a hybrid IEM with a choice of 3.5mm, 4.4mm or a Type-C DSP version.
Skip if
You need impedance and sensitivity figures or a microphone on the 4.4mm version.

Why 3.4/5: No specification list in the page text and the store's own contradictory terms hold the rating back, as does the fact that no independent test was checked for this review.

Tanchjim's OLA II is the successor to the OLA, and the page lists it from $75.20 as a hybrid: a 10mm DMT5 dual-magnetic, dual-cavity dynamic driver paired with a Pure Hi balanced armature in a coaxial arrangement. The cable is detachable on 0.78mm 2-pin connectors and comes with a 3.5mm, 4.4mm or Type-C termination. The page text carries no impedance, sensitivity or frequency figures.

Specifications

SpecPage says
Dynamic driver10mm DMT5, dual-magnetic circuit, dual-cavity
Balanced armaturePure Hi ultra-high frequency BA driver
Driver layoutCoaxial hybrid
SimulationFEA-optimized diaphragm movement and sound path tubes
FaceplatesCNC-machined aluminum alloy
Inner cavityTransparent PC material
Pressure reliefExternal air-pressure relief design
Ear shape dataOver 3000 human ear shapes
Cable connectorDetachable, 0.78mm 2-pin
Terminations3.5mm, 4.4mm or Type-C
Type-C DSP32Bit/384kHz processing, 8-band PEQ
MicrophoneMEMS in-line, 3.5mm and Type-C versions

Options and pricing

Three terminations are listed, all orderable when the page was read: OLA 2 3.5mm at $75.20, OLA 2 4.4mm at $76.50 and OLA 2 Type C at $79.20. The option field is labelled Color, but the names differ by termination. Per the page, the Type-C version adds DSP functions with an 8-band PEQ and 32Bit/384kHz processing through the Tanchjim app on Android, and the 3.5mm and Type-C versions carry a MEMS in-line microphone; the page text names no microphone for the 4.4mm version.

How it compares

Among the siblings, the TWISTURA Sigma 1DD+1BA Hybrid Driver In-Ear Earphone is another hybrid, from $65.90, and the Pula Audio Unicrom 10mm Single Dynamic Driver IEMs are a single dynamic model at $74.99. For a planar alternative, the FiiO FP3 14.5mm Planar Driver In-Ear Earphone is $89.99. The OLA II suits buyers who want a hybrid with a choice of 3.5mm, 4.4mm or Type-C DSP; the sibling summaries here say nothing about their plugs, so check those pages.

Shipping, returns and warranty

HiFiGO sells from hifigo.com and says every order leaves its warehouse in China, usually 1-3 business days after it is placed, and says its delivery times are estimates, not promises. Its shipping policy gives the United States 1-2 weeks (about 10 days on average) by Priority and 6-10 days by Premium, both with duties and taxes prepaid by the store; Canada 2-3 weeks; the United Kingdom 1-2 weeks; and Australia 10-15 days. Express couriers (DHL, UPS, FedEx) take 3-7 days, but then the buyer pays any duties and taxes. No shipping page names New Zealand, PO boxes are not accepted, and the free-shipping thresholds differ between the store's own pages, so check the cart. One of its two shipping pages adds that a lost parcel on an order above $50 gets only a 50% refund. A US buyer reported a $40 tariff charge in August 2025, after which HiFiGO said it had added a customs notice at checkout.

Read the return terms before you order. The homepage advertises 7-day returns. Both of HiFiGO's policy pages offer a 7-day dead-on-arrival cover (a replacement or a full refund, with the return postage refunded) and also describe 30-day returns, but a request made 7 to 30 days after delivery loses 30% of the MSRP as a restocking fee (10% more if the packaging is incomplete), plus shipping both ways and duties, and the FAQ on the same pages says there is no refund or exchange once 7 days have passed. One version recommends reselling an opened product locally. Custom IEMs and custom cables cannot be returned, no return address is published, and buyers describe sending items back to China.

HiFiGO's warranty runs one year from the order date for parts and labor; its policy names desktop DACs and amps, IEMs and dongles at one year and gives cables and adapters three months. HiFiGO decides between repair and replacement, the buyer pays the shipping, and faulty items go back for service, not for a refund. Claims go to [email protected], the only contact the store lists: its pages name no company, street address or phone, and its terms are governed by the laws of China.

On Trustpilot, HiFiGO had 4.6 out of 5 from 378 reviews when we checked on 2026-10-28 (91% five-star, 5% one-star), and it had replied to about 75% of negative reviews; Trustpilot notes the store has not invited customers to review recently. The one-star reviews mostly concern the short return window and the deductions on returns, items listed in stock that turned out back-ordered, slow email support and a tariff charge on a US delivery in 2025. HiFiGO says its products are genuine and come in the brands' retail packaging; it does not claim to be an authorized dealer.

What we liked

  • Hybrid pair: a 10mm DMT5 dynamic driver and a Pure Hi balanced armature, per the page
  • Three terminations: 3.5mm, 4.4mm balanced or Type-C
  • Type-C version lists DSP, an 8-band PEQ and 32Bit/384kHz processing
  • Detachable cable on 0.78mm 2-pin connectors
  • MEMS in-line microphone on the 3.5mm and Type-C versions

Worth noting

  • Impedance, sensitivity and frequency response are all missing from the page text
  • The page text names no microphone for the 4.4mm version
  • DSP and PEQ are tied to the Tanchjim app on Android; the page text names no other platform
  • The Type-C DSP figure is given but no DAC chip or output figure is named

Questions before you buy

What drivers does the OLA II use?

The page describes one 10mm DMT5 dual-magnetic, dual-cavity dynamic driver and one Pure Hi balanced armature driver for the ultra-high frequencies, arranged coaxially. The page text gives no impedance or sensitivity figure.

What does the Type-C version add?

Per the page, DSP functions with a built-in 8-band PEQ and 32Bit/384kHz audio processing, used through the Tanchjim app on Android. It is $79.20, against $75.20 for the 3.5mm version and $76.50 for the 4.4mm.

Which versions have a microphone?

The page says the Type-C and 3.5mm versions have a MEMS in-line microphone, and it names none for the 4.4mm version. No sensitivity or SNR figure is given for the microphone.

Where does HiFiGO ship from, and how long does it take?

From its warehouse in China, usually 1-3 business days after the order. The shipping policy gives 1-2 weeks to the US by Priority (6-10 days by Premium), both with duties and taxes prepaid, 2-3 weeks to Canada, 1-2 weeks to the UK and 10-15 days to Australia. Express couriers take 3-7 days, but the buyer pays any duties.

Can I send it back if I change my mind?

HiFiGO gives 7 days to report an item that arrives dead, damaged or wrong. Its policy also describes 30-day returns, but requests 7 to 30 days after delivery lose 30% of the MSRP plus shipping both ways and duties, and the FAQ on the same page says no refund or exchange after 7 days. Ask [email protected] before you open the box.

What warranty does HiFiGO give?

One year from the order date for parts and labor, for faults in build or materials (the policy names desktop DACs and amps, IEMs and dongles; cables and adapters get three months). HiFiGO chooses repair or replacement, the buyer pays the shipping, and a faulty item is serviced rather than refunded. Claims go to [email protected].

Sources & verification

What this review is based on and the day we last read it. Specs and claims from the maker are the maker’s own; the verdict and the rating are ours.

From the store

  • Tanchjim OLA II / OLA 2 10mm DMT5 DD + Pure Hi BA Hybrid IEMs product page: specs, options and priceSpecs, options and the listed priceRead October 28, 2026
  • HiFiGO shipping policyShips from China in 1-3 business days; US 1-2 weeks by Priority or 6-10 days by Premium, duties prepaid; Express buyers pay dutiesRead October 28, 2026
  • HiFiGO shipping and order tracking pageA second shipping text: Premium also for Canada and Australia, Canada free shipping from $99.99, lost-parcel rulesRead October 28, 2026
  • HiFiGO refund policy7-day dead-on-arrival cover; 30-day returns minus a 30% restocking fee; its FAQ says no refund after 7 daysRead October 28, 2026
  • HiFiGO warranty and refund policyWarranty by product class (1 year; cables and adapters 3 months); 30% fee for resealing an opened productRead October 28, 2026
  • HiFiGO terms of serviceOperator named only as HiFiGo; governed by the laws of China; contact [email protected]Read October 28, 2026

Independent

  • HiFiGO reviews on Trustpilot4.6 of 5 from 378 reviews (91% five-star, 5% one-star); the store has not invited reviews recentlyRead October 28, 2026

What we couldn’t verify

  • The page text gives no impedance, sensitivity or frequency response; the 32Bit/384kHz figure is for the Type-C version's DSP processing, and no DAC chip or output figure is named.
  • Build claims (aerospace-grade aluminum) and high SNR for the microphone come with no standard or number; sound claims (seamless resolution, punchy lower end, airiness) are the page's wording.
  • HiFiGO's policy pages contradict each other: 30-day returns with a 30% restocking fee in one place, no refund or exchange after 7 days in the FAQ.
  • HiFiGO's pages name no company, street address or phone number; the only contact given is [email protected].

Spotted an error or something out of date? Tell us and we’ll fix it and update the date.

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