Chanel imbalance issue
"Had one of tubes fail; upon inspection... they were not a matching pair to begin with...my only complaint is for QC / Xduoo to test and match the tubes!"















The MT-02 is a desktop hybrid tube headphone amplifier that combines dual 6J1 vacuum tubes with a transistor-based Class-A output stage for a tube-forward presentation of warmth, detail, and driving power. Designed for a wide range of headphones, it features both 4.4mm balanced and 6.35mm headphone outputs, adjustable gain, pre-out functionality, premium audio components, and a compact aluminum chassis with transparent acrylic panels that reveal the amplifier's internal architecture.
The MT-02 uses a hybrid amplifier topology that pairs dual 6J1 tubes in the voltage gain stage with a transistor-based Class-A output stage. This design delivers the smooth tonal character and rich midrange associated with vacuum tubes while providing the current delivery and control needed to drive demanding headphones.
Two 6J1 vacuum tubes work in the preamplification stage, contributing warmth, natural vocals, and smooth high frequencies. The tube stage helps preserve musical detail while creating a relaxed, fatigue-free listening character that complements both modern and classic recordings.
The transistor-based Class-A amplification stage provides up to 1,500mW into a 32Ω load, giving the MT-02 the ability to power everything from efficient portable headphones to higher-impedance designs. High current delivery, fast transient response, and controlled bass help maintain clarity across dynamic passages.
Front-panel 4.4mm balanced and 6.35mm single-ended headphone outputs provide compatibility with today's most common headphone connections. A selectable high and low gain switch makes it easier to match output levels with different headphone sensitivities.
The integrated pre-out allows the MT-02 to function as a tube preamplifier for external amplifiers or powered speakers. Volume remains synchronized through the front-panel control, making it easy to integrate the amplifier into a desktop or two-channel listening system.
ELNA audio coupling capacitors and Rubycon filter capacitors are used throughout the analog circuit to support low noise, stable performance, and consistent signal quality. The amplifier also incorporates an external ground terminal that helps reduce hum caused by grounding issues in connected equipment.
An intelligent relay protection system introduces a 30-second startup delay that allows the tubes to warm before audio playback begins. The circuit also minimizes power-on and power-off pop noise while providing overload and short-circuit protection for both the amplifier and connected headphones.
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Overall rating: 4.0 / 5 from 3 reviews.
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"Had one of tubes fail; upon inspection... they were not a matching pair to begin with...my only complaint is for QC / Xduoo to test and match the tubes!"
"I didn't buy mine from Apos but own it and love the guys here and always buy from Apos when I can for the impeccable post purchase support and advice. As much as I love my Gremlin (with RCA Long 17mm Black Plates, White block text/logo, angled square getter late 50s 12au7 upgraded tubes) , I have to say, this triode-strapped pentode tube config. (pentodes wired as "fake triodes") in it's unbalanced output design (the 4.4 here is NOT A REAL Bal. connection, but simply essentially a 4.4 to 3.5 UNbalanced "internal adapter" that just pushes more power into it), it sounds better than my Gremlin (with upgraded 50s black plate Vintage NOS 6ak5/ef95/xyz upgraded tubes). Probably has to do with the fact that the Gremlin is geared towards a very low noise fully balanced system with good crosstalk #s etc) AND because the MT-02 pushes the triode-strapped pentodes pretty hard in a "noiser" SE config. HOWEVER ***ALL OF THIS NEXT TEXT IS WITH THE MT-02 ON --LOW GAIN--*** THERE IS 1 MASSIVE ISSUE for sensitive headphones like my Meze 105-AER or Aune Ar5000 and especially for IEMs , even my hardest to drive Mega5-EST IEMs have this issue: there is pretty bad channel imbalance (one side louder than the other ear) between 7 and 9 o'clock on the Volume pot. BUT the pot shoots up from 0 to 100 so fast that at 8 or 9 o'clock EVEN WITH A -15dB Pre-Gain EQ settings, a humble 2Vrms DAC feeding the mt02 makes the IEMs and easier to drive headphones SUPER SUPER LOUD. you end up having to kill the windows/audio program volume to low amounts to compensate which reduces the bit-depth and dynamic range... the iFi IEMatch+ or IEMatch4.4 are 100% NECESSARY for this amp to function properly for IEMs (do not use this device with headphones you will make them sound bad I won't get into the electrical details. ALSO- do not just buy a cheap impedance adapter off of AliExpress it will destroy the freq. response of your IEMs. it needs to be an L-Pad attenuator voltage divider array to not mess up the tuning. For slightly harder to drive Headphones (think 60 ohms 105 sens) and harder it is just fine. for IEMs and super easy to drive Headphones like my Meze 105-AER and Aune Ar5000 MK1 it is a DEFINITELY a big problem... if you are gonna use the mt02 with such devices, for IEMs you NEED the IEMatch and for easy to drive headphones you'll need to apply a pre gain -dB filter as well as turn audio program and windows volume down to get you to that 11-ish o'clock position where there is no imbalance. IF THEY JUST made the volume pot less of an exponential curve and gave more headroom down low on the knob it would be an 11/10 with rolled premium tubes. AND THANKFULLY 6j1 and its brother variants like 6ak5 etc. are CHEEEEEAAAP even for the premium ones which is a massive plus."
"Just excellent."