If you need a simple interface for solo instruments or talking head, there are numerous two-channel interfaces available for around $200. The Topping E2x2 OTG, released late in 2025, is a newcomer to the audio interface market but has carved out a niche in the two-Benjamin club. Do the features and audio quality measure up to the likes of MOTU and Scarlett?

E2x2 OTG in the Wild | Tiny Topping atop a Tascam.

I use audio interfaces for recording my classical guitar and ukulele on a Mac computer in my home studio. Oh, and the occasional video tutorial for YouTube. This review will contain no scientific measurements, colorful graphs, or singing. Just thoughts and observations on my experiences with the Topping E2x2 OTG.

Construction

The outer case of the Topping E2x2 OTG is made of two thin pieces of aluminum held together with hex bolts. It weighs a mere 530 g, so keep a firm grip on it when inserting or pulling cables. It's available in matte white and black finishes. I chose white for better visibility in my dim bedroom studio. Black audio gear is hard to see in low light. The E2x2 OTG is durable enough for desktop use but feels flimsy compared to the rolled steel case of my Tascam 208i interface. No plastic other than the feet, knobs, switches, and input/output jacks. The case design is conventional but handsome with a good fit and finish.

RFI Resistance

The metal case and internal circuit design provide excellent RFI shielding. Here in RFI-prone downtown Honolulu, no static, clicks, or rogue radio stations were heard on tracks recorded with the E2x2 OTG. I recorded within inches of my iPhone and detected no chirps or hiss. 

Controls

Major interface functions have physical controls on the front panel, and these controls are logically placed and clearly labeled. Some owners complain that the headphone gain and mix dial are too close, but they work fine for my medium-sized fingers. Maybe it helps to be a guitar player.

Switches, dials, outputs, and inputs have no play. Dials rotate smoothly but with some resistance, minimizing inadvertent adjustments. Switches illuminate with color-coded LEDs when engaged—great for dim studios.

Topping E2x2 OTG | Two XLR combo jacks | Image courtesy Topping

XLR Combo

Two XLR combo inputs adorn the front panel. XLR mics, high-impedance instruments, and line-level signals are compatible. These inputs may be used for stereo (two channels at once) or mono (one channel) recording.

Each XLR combo input has a gain dial and buttons for direct input monitor, phantom power, and instrument/mic mode. With individual controls for each channel, mics requiring different settings may be recorded simultaneously. For example, a condenser mic requiring phantom power and a ribbon mic that can be damaged by phantom power can be used together for stereo miking.

There is no line-level button, but line-level is the default for TRS input. For high impedance instrument signals—e.g., electric guitar or bass—press the INST button to change the input impedance for instrument pickups.

Meters

These meters are exceptional in this price class—clip LEDs or new age hippie colors on a gain dial are more typical—and actually useful for gain staging.

Power

Hallelujah, the E2x2 OTG has a power switch! It's a rear-mounted rocker switch, easy to find by feel and has a satisfying snap when flipped. I would have bought a different interface if the E2x2 OTG lacked a power switch.

Topping E2x2 OTG | Praise be, a power switch! | Image courtesy Topping

For computer use, the middle USB-C port transfers data and power to the E2x2 OTG. I plug the unit into a powered USB-C hub, and it works perfectly with my Mac Studio M4 Max. Yes, a direct connection to the computer is preferred, but I'm juggling four audio interfaces, three hubs, printer, scanner, a fleet of hard drives, and an Elgato Stream Deck!

For phones, tablets, and older computers that lack sufficient power for operation via USB-C, a second power-only USB-C port (far left) is used for auxiliary power.

Connectivity

Inputs

The E2x2 OTG, like the original E2x2, is a basic 2-in/2-out design. In other words, it has two input channels for mics or instruments and two output channels for stereo monitors. The star of the show are the two ultra-linear mic preamps with 58 dB of gain, 115 dB dynamic range, and -130.5 dBu EIN. I characterize them as ultra-clean and neutral and, along with the great headphone amp, one of the reasons I chose the E2x2 OTG. 

Most of the preamp gain adjustment range is smooth and even, but near 3 o'clock jumps to larger increments. You may not notice with condenser mics since they have modest gain requirements, but I tried a Shure SM57—a gain-hungry dynamic mic—and noticed the large gain jump near the end of the range.

Topping E2x2 OTG | Two XLR combo jacks | Image courtesy Topping

A mysterious third channel labeled OTC is found on the rear panel. OTG stands for USB On-The-Go, a technology allowing smartphones and tablets to host USB peripherals without a computer. For example, you may connect the E2x2 OTG to an iPhone to live stream audio to YouTube. I don't have any use for OTG, but network gamers and podcasters will like it. A specical USB OTG cable—not included—is required for this feature to work. 

Outputs

The primary audio outputs are the stereo headphone jack (1/4") and two TRS outputs on the rear. All the outputs you need for monitoring monophonic and stereo recordings. I have the 1L and 2R mains connected to KRK Rokit 5 monitors. Plenty of signal to drive these monitors at desk-rattling volume.

If you're a budding movie producer, know that surround sound monitoring is not feasible with only two outputs. You need an interface with at least eight outputs for 7.1 surround sound (seven monitors and a sub woofer).

Topping E2x2 OTG | Image courtesy Topping

The E2x2 OTG also has a mini-pin (3.5 mm) AUX stereo output to connect to consumer speakers or DJ gear, and an OPTICAL OUT (SPDIF) to transmit the mains as digital data for outboard processing.

Headphones

Home studio musicians spend most of their production time editing and mixing tracks, not recording. And much of this work is done with headphones, making the headphone amp the most used feature of an interface. 

The secret weapon of the E2x2 OTG is its great headphone amp, likely adapted from Topping's Wi-Fi designs, and besting performance of more expensive interfaces. Indeed, Topping's NFCA-LE headphone amplifier module sounds excellent and has ample gain—output of 580 MW x 2@RL=32 Ohm—to drive my 300 Ohms (Ω) Sennheiser HD650 and HD580 headphones. The E2x2 OTG has a front panel gain boost switch to add an additional 17 d Bu for the rare gain-hungry 600 Ohms cans.

Does the E2x2 OTG sound better than my iFi Zen Can headphone amp? Nope, but it's only a stone's throw away and better than most interfaces I've owned.

MIDI MIA

I'm an acoustic musician and don't use MIDI. However, if connecting MIDI controllers, drum machines, and synths is important to you, buy a different interface. The E2x2 OTG doesn't have MIDI. Fortunately, many music-focused interfaces in the same price range as the E2x2 OTG are equipped with MIDI: MOTU M2, Tascam US-2x2HR, Arthurian Mini Fuse 2, etc.

Topping E2x2 OTG | Illuminated buttons engaged during a mix session.

USB

The E2x2 OTG sports three USB-C ports, using them for power and connection to computers, tablets and phones. Two meter USB-C to USB-C and USB-C to USB-A cables are included in the box.

Software

Mac Drivers Not Needed

The E2x2 OTG is Core Audio compliant. In other words, plug-and-play on the Mac and requires no drivers. I'm running Sequoia 15.7.4 and all is well.

I’ve tracked with the E2x2 OTG on a Mac Studio M4 Max using TwistedWave, GarageBand, Adobe Audition, and Logic Pro X without problems. Power on the E2x2 OTG before opening the DAW, and it is immediately recognized. No restarts or cable pulls required.

Topping Professional Control Center

A humble application with a grandiose title—Topping Professional Control Center (Pro Control)—is the only software supplied. While optional for Macs, it is required for Windows. Pro Control is used to configure loopbacks, routing, digital gain, and some physical controls. Sample rate buffer settings are available for Windows but not for Macs. For Macs, buffer and sample rates are configured in the DAW.

XLR preamp gain for the IS not controllable with this app. However, Pro Control has 20 dB of digital gain available if needed for gain-hungry dynamic mics.

Pro Control | Input/output routing, digital gain, and firmware updates.

Streamers may find the three stereo channels of loopback from digital sources useful. For example, play a track from a DAW while talking to a phone guest during a live stream. The E2x2 OTG retains the last setting even if Pro Control is not open.

Latency

Latency refers to a delay in the transmission of audio data, i.e., sound. To synchronize playing with a multitrack recording, I monitor backing tracks with headphones. If there is a significant sound delay in the headphones, my playing will lag behind the beat. Thus, low latency is important for successful recordings. Most companies claim zero-latency monitoring, including the Topping E2x2 OTG. Is this claim real, useful, or marketing hype?

Zero Latency?

With a press of the MON switch, zero-latency direct monitoring is available on the E2x2 OTG. When engaged, you hear only your input, e.g., your playing or singing through channel 1 or 2. DAW tracks and metronome are muted. MON is useless for multitrack recording where one needs to synchronize with backing tracks. I sometimes use MON for a quick sound check—listen for sound bleed, outside noises, etc.—but that's it.

MON is also redundant because the Monitor Balance dial engages direct input monitoring by rotating it to the far left. Plus, Monitor Balance can mix DAW and input signals—an essential feature for multitrack recording.

Monitor Balance

I need to hear backing tracks when recording, so I manage latency by mixing input and DAW signals and by configuring gear and software for optimal speed.

I prefer the Monitor Balance mix at 10:00 to 11:00, i.e., with stronger input signal but with DAW playback still audible.

Optimize DAW Settings

Latency is affected by the configuration and speed of the audio interface, DAW, and computer. For example, latency may be reduced by increasing the sampling rate and/or reducing the buffer size. With Logic Pro X set to 48 kHz with an I/O buffer size of 32 samples, the system calculates round trip time as 7.6 ms. I don't know how accurate this time is, but it's fast enough for me to synchronize with the backing track. At 96 kHz and an I/O buffer size of 32 samples, round trip is estimated at 6.9 ms.

Higher sample rates and smaller I/O buffer sizes increase CPU demand. If pushed too far, recording dropouts may occur with slower CPUs. My Mac Studio M4 Max has no dropouts at any setting, but my MacBook Pro i5 didn’t fare as well.

Latency may be reduced by disabling DAW plugins during recording sessions.

Logic has a low latency recording mode, further reducing the lag of backing tracks over headphones. With most of the above measures in place, latency has not been an issue for multitrack recording on the E2x2 OTG.

Sound Quality

Instruments

I record multitrack and stereo recordings of classical guitar and ukulele, mostly demostrations for college courses I teach or for my YouTube channel. I mainly use Neumann KM 184 and TLM 102 condenser mics, which deliver a crystal-clear sound on the E2x2 OTG and need few EQ tweaks. Condenser mics require phantom power, so the 48v button was engaged.

Here's an example of how a Kremona Coco tenor ukulele sounds in a mix as a melodic instrument using two Neumann KM 184 condenser mics in a X/Y stereo configuration pointed at the bridge. Gain was at the 1:00 o'clock position. I used two octaves of Coco's range (up to the 12th fret) and managed a few natural harmonics in my original composition, Leeward Coast Redux:

Leeward Coast Redux | by Peter Kun Frary | Kremona Coco and Mari ukuleles, Hirade H8SS guitar and small percussion | Neumann KM 184 mics, E2x2 OTG, Logic Pro.

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The ritornello from Jesu, Joy of Man's Desiring was recorded using two Neumann KM 184 mics in a X/Y stereo configuration pointed at the bridge.

Jesu, Joy of Man's Desiring | Romero Creations Tiny Tenor 6 guilele | Neumann KM 184 mics (2X), E2x2 OTG and Logic Pro.

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The individual tracks of the Brazilian Lullaby were recorded in mono using a Neumann TLM 102 condenser mic aimed at the bridge of the ukulele. For finger picked ukulele, a close-mic’d Neumann TLM 102 needs gain at about the 2:00 o'clock position.

Brazilian Lullaby | Cordoba and Romero Creations ukuleles, Neumann TLM 102 mic, Topping E2x2 OTG and Logic Pro.

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The above tracks were mixed using Beyerdynamic DT 770 Pro X headphones and KRK Rokit 5 Gen 5 monitors plugged into the E2x2 OTG. The Topping DAC renders audio clearly and accurately—almost too much detail! I check the final mix with Sennheiser HD650 and Apple AirPods to make sure they translate to other sound systems.

Topping E2x2 OTG | The buttons—MON, 48C, STR, etc.—are white switched off but change color when engaged. | Image courtesy Topping

Spoken Word

For classical guitar and ukulele, I prefer the sensitivity and response of condenser mics. For spoken word, I reach for the more forgiving response of dynamic mics—mics that don't require phantom power. The gotcha of dynamic mics is that they require more preamp gain than condensers. Can the E2x2 OTG deliver enough gain for this soft-spoken music professor?

E2x2 OTG maximum preamp gain is 58 dB, a little low for dynamic mics. However, these preamps are clean when set to maximum, so extra gain may be added in post-production with excellent results. I usually do it in Logic Pro, but an additional 20 dB of digital gain is also available in Topping Pro Control.

Below are a couple short audio samples of spoken word. For the samples, I spoke 8 to 10 cm away from a Rode Podmic USB dynamic mic, a popular podcasting mic. The PodMic was mounted on a Elgato boom clamped to a desk in a partially treated room. I recorded into TwistedWave at 48 kHz and 24 bits. No processing was used other than normalization to equalize sample volume. A foam pop filter was installed. 

Rode X Streamer | The Streamer X interface boats ultra-low-noise, high-gain (76 dB gain and -131.5 dBV EIN) Revolution Preamps, ideal for dynamic mics.

Rode PodMic USB and Streamer X

XLR output of the PodMic USB was plugged into the Rode Streamer X with gain set to 63 dB, resulting in a -12 dB average. No processing was used. The Streamer X is designed with dynamic mics in mind and has an amazingly clean preamp with up to 76 dB of gain.

Rode PodMic USB and E2x2 OTG

XLR output of the PodMic USB was jacked into the Topping E2x2 OTG and gain set to maximum. I hoped to see an average of -12 dB but only managed about -18 dB. No processing was used other than normalization to match the Streamer X levels. Even with normalization, this sample is clean and noise-free.

Dynamic Mics and the E2x2 OTC

Back to my earlier question, “can the E2x2 OTG deliver enough gain for this soft-spoken music professor?” Well, sort of: it's good enough in a pinch with digital gain added. Levels were boosted 6 dB to hit the -12 dB average with the PodMic USB. The Shure SM57 and SM58 need even more, about a 10 dB boost. I don't own a SM7B to test, but it is known to have considerably less output than the Podmic USB, SM57, and SM58. For spoken word with dynamic mics, I'll stick with my Streamer X. The squeaky clean 76 dB gain preamp spares me from extra knob diddling in post-production. Wish I had a music interface with those preamps.

Musings

The E2x2 OTG is a wonderful piece of kit, and I enjoyed recording and mixing with it. Audio quality between the E2x2 OTG and twice as expensive Tascam 208i is very similar. As a solo musician, the E2x2 OTG gives me the audio quality and basic tools I need but without any extras or advanced features. However, the E2x2 OTG is not a game changer in a crowded market of similarly priced interfaces. Its main distinguishing characteristics over the Scarlett 2i2 and similar interfaces are a better headphone amp, calibrated meters, monitor mix control for input and DAW signals, and a power switch. 

Most interfaces in this price range ship with a DAW and plugins, and the E2x2 OTG, well, has nothing. Nada. That's okay with me, a hardened Logic Pro user, but a novice will need to find a DAW app before they can record. If you're a Mac user, a good entry-level DAW is on your computer: GarageBand. 

Who is this interface for?

The E2x2 OTG is ideal for a singer-songwriter or solo instrumentalist recording at home with condenser mics and/or electronic instruments. With the OTG and loopback features, it's also well suited for streamers unwilling to spring for a RodeCaster Pro.

Somebody who primarily uses low-output dynamic mics like the Shure SM7B should stay away from the E2x2 OTG. Well, unless you already own a Fethead preamp. It’s also not for those planning to record large ensembles, drum kits, or produce surround sound. These users should look for an interface with more input and output channels, ADAT expansion, MIDI, etc.

Alternatives

If you don't need OTG, AUX, or optical output features, the Topping E2x2 (white) or Topping E2x2 (black) is the same as the E2x2 OTG otherwise but for $40 USD less.

Final Blurb

The Topping E2x2 OTG is bare bones in terms of features and expandability, but is well made, attractive, plug-and-play on Macs, requires little desktop space, and records and plays back audio cleanly and accurately. It works each and every time I flip the on/off switch. No restarts, cable pulling, or drivers are needed for me. Such reliability allows me to stay in my happy place and concentrate on making music. 

Finally, please help support this website by purchasing the white Topping E2x2 OTG at Amazon. If you prefer black, buy this E2x2 OTG instead.

Crescent Moon at Ala Moana | ©Peter Kun Frary

Major Features and Specs

2 ultra-linear mic preamps with 58 dB of gain and 115 dB dynamic range

Individual 48 v phantom power switches for preamps

2 XLR/TRS combo inputs

2 balanced TRS mains out with 127 dB dynamic range

optical (SPDIF) output

3.5 mm TRS AUX output

6.35 mm (1/4") headphone output (NFCA-LE) at 580 mW x 2@RL=32 Ohm

3 USB-C 2.0 ports (computer, OTG and power)

Up to 192 kHz/24-bit WAV recording (44.1, 48, 88.2, 96, 176.4 and 192)

Frequency Response of 20 Hz–40 kHz (+/- 0.2 dB)

Zero-latency direct monitoring with MON switch engaged

Included accessories

USB-C to USB-C and USB-C to USB-A cables

3.5 mm stereo to 6.35 mm stereo adapter

Size and Weight

18.7 cm x 12.9 cm x 5.0 cm (W×H×D)

530 g

Country of Origin

People's Republic of China

Instruction Manual

Manual

Price

$199.00 USD

Website

Topping USA

03/03/2026

©Copyright 2026 by Peter Kun Frary | All Rights Reserved