Ichos

Reviewer at hxosplus
Precision meets enjoyment
Pros: - Neutral and transparent
- Musical and entertaining
- Powerful with three gain settings
- Dead silent
- Excellent timing
- Resolving but not analytical
- Suitable for sensitive iems
- Full aluminium enclosure
- Great build quality
- Fully balanced design
- Balanced pre - amplifier
- Both 4 - pin XLR and 4.4mm outputs
- Budget friendly
Cons: - A touch lean
- Not forgiving
- Slightly lacking in dynamics and holography
The HO200 was kindly provided by Aoshida Audio free of charge.
They never asked for a favorable review and this is my honest and subjective evaluation of it.
All links below are not affiliated and I don't get commission by clicking on them.
The HO200 price is $399 and it is available by the Aoshida Audio store.

Introduction

SMSL

SMSL is by now, a well known and established brand from China focusing mostly on headphone amplifiers, DACs and Class D stereo amplifiers.
The company is committed to producing value for money products with a rich set of features, excellent performance and top notch measurements.
They have been learning from the past and are attentively listening to customer feedback in order to keep improving.
And this is true because for the past five years that i have been following the brand there is an obvious development regarding craftsmanship and sound quality.

Aoshida Audio

Aoshida Audio is one of the leading e - commerce platforms from China which specializes in providing audio products with excellent service and striving to make continuous improvement.
They offer an authenticity guarantee for everything they sell, lowest price and 2 year warranty plus a 50-day return policy on all the products.
You can visit them here.

The SMSL xO200 series

The SMSL xO200 series is an exclusive collaboration between the brand and Aoshida Audio to produce some unique and value for money audio products on specifications set after carefully considering the needs of the market.
The first product of the series was the AO200, a small Class D integrated amplifier that I have already reviewed here.
The HO200 headphone amplifier is the second installment of the series to be followed by it's partnering DAC, the DO200. (review)

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SMSL HO200 design and technical specifications

The SMSL HO200 is a compact but powerful headphone amplifier and preamplifier with an output stage capable of delivering up to 6Wx2 under 16Ω or 3Wx2/32Ω from the balanced output, suitable for desktop use with headphones and active speakers.
It is a fully balanced audio circuit that incorporates 4 ultra-low distortion linear feedback loops (an exclusive topology of SMSL) based on the OPA564 and is powered by an ultra low noise power supply design.

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The distortion rate of the HO200 thus reaches 0.00006% / 0.000005% A-WTD, or -126dB, which is an impressive performance capable of revealing all the qualities of the audio signal.
A high quality relay system can completely avoid all pop noises caused by on/off action, and input/ output changes during playback, to suppress any noise that may disturb the listening experience and protect the connected headphones.
As per usual SMSL practice all components to be found inside the circuit are genuinely branded and of the highest quality.

I/O and user interface

At the front of the HO200 is a balanced headphone output on an XLR-4 pole connector, a balanced output on a 4.4mm jack connector as well as a single ended output on a 6.35mm jack connector.
So it is possible to work natively with various headphone cables without the need to use an adapter.
At the center there is an aluminum volume control knob with excellent user feedback and a smooth, scratch free and tight rotation for doing fine adjustments.
The potentiometer is a special design to offer low channel imbalance and good tracking from the lowest setting.
At the right side there are four aluminium, classic style toggle switches for choosing between XLR and RCA input, headphone or preamplifier operation, three gain settings (low, medium and high) and ON/OFF.
At the back there is a power AC switch, power AC input, XLR and RCA pre-outputs and finally the XLR balanced and RCA unbalanced inputs.

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Build quality

The device is housed inside a durable, full aluminum CNC machined chassis of medium thickness, which also acts as a shield to block outside any kind of electromagnetic interference.
The craftsmanship and finish are top notch and the device has a minimalistic simplicity with an elegantly beautiful appearance.
Thumbs up here for the design and the build quality.
The AO200, HO200 and DO200 share the exact same appearance so they can be stacked together to make a beautiful and minimalistic sound system to cover both headphones and speakers.

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Listening set-up and power output

As per usual practice and prior to critical listening tests, the amplifier was left burning for about 100 hours.
At the beginning the sound was a touch harsh but then it gradually improved, evolving into a smooth sounding amplifier.
The amplifier was paired with the SMSL DO200 DAC (review to follow) and the Denafrips Ares II, kindly loaned by www.denafrips.eu.
Transport duties were handled by the Allo DigiOne Signature alternating with the ZEN Stream and everything was plugged into an iFi Power station.
Various headphones were used like the Sennheiser HD660S/HD650, HiFiMan Sundara, Focal Clear Mg and many others both from the balanced and single ended outputs.
All headphones were driven with a great sense of authority and extra headroom while the only time I found the need to reach high gain was to drive the HEDDphone although mid gain was already sufficient at about ¾ of the available volume.
Furthermore the low gain is specially optimized for sensitive iems and truly the amplifier was dead silent with everything I have used.

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Listening impressions

I don't have the means to perform measurements but I bet that the HO200 should prove to be a perfectly measuring amplifier.
And the certainty was born during the listening tests since the amplifier proved to be extremely transparent, precise and linear, demonstrating the highest level of fidelity.
The background is pitch black, there is no sign of distortion and as that the sound is crystal clear and resolving, exhibiting a great depth of inner detail but without venturing into a synthetic analysis.
If you hear noise then there must be something wrong with your DAC or the power supply that you should immediately check.

Sometimes people get scared reading about transparency, fidelity, linearity and measurements thinking that the amplifier in discussion should be clinical and not emotional.
Well, there is a chance that they could be right but not this time because the HO200 is the exact opposite since I found it to sound engaging and musical with a great sense of involvement.
There is plenty of harmonic wealth, natural timbre and textural quality to draw a convincing picture of the music.
It is not the last word in timbral saturation and can't reach the scale and grandeur or the organic timbe some of the best discrete solid state and tube amplifiers can do but the HO200 still fares well and sometimes far better than the competition be it discrete or not.

The bass is extended without rolling off and sounds tight, controlled, fast and precise with great timing while the overall presentation is on the leaner side, slightly lacking in body and fullness but this helps a lot with layering and definition when the bass line gets full and busy.
Vocalists and instruments of the mid - range sound convincing with a rounded, excellent phrasing, a realistic projection and some natural texture and timbre.
The treble extension is infinite, high pitched instruments sound agile and full of energy, notes are finely articulated with a crystalline quality to them, slightly skinny and rushed, while the overall character is luminous, venturing into the realm of brightness but thankfully not overly so as to become harsh and fatiguing.
It is not about tonality deviation but rather more about the honesty of the presentation, the user should not expect the HO200 to smooth things out and paint the blanks with some appealing pastel colors.
The amplifier is not forgiving at all and it is the chain "recording - source - headphone" that will determine the final results that will reach your ears so some clever matching will yield the best results.
The soundstage, especially from the balanced output, is spacious and wide, only slightly lacking in overall depth and holography but still everything is presented with a realistic manner, accurate positioning and a good sense of time and space.

As a final note I should say that I am very happy with the SMSL - Aoshida series and all three products pair well together and can form a great value for money combination system to successfully cover headphone and speaker listening alike.

At the end

The SMSL HO200 easily ticks most of the boxes in my checklist and counts as a winner and an instant recommendation.
With excellent craftsmanship and superb sound quality it will appeal to all fans of transparency and fidelity without sacrificing much in musicality and entertainment.
With power to spare and a very friendly price tag it should easily count as an end game headphone amplifier and pre - amplifier for a lot of people that need something reliable and good sounding without breaking the bank.

Test playlist

Copyright - Laskis Petros 2021
Last edited:
fortunate son
fortunate son
Really like this review. You make it very clear why you like the amp. I only wish I experienced what you do.
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Ichos
Ichos
If you agree with my review then you should have decided to keep it from the beginning!
Anyway, maybe because this is a fast and agile amp with enough voltage swing, it pairs well with your HD600.
fortunate son
fortunate son
This thing is versatile. Mucho power and "gain". Works with everything: iems, dynamics and even finicky planars like the HE6SE.

Too bad about its sound on most every headphone I've tried it with. Mark Levinson hits the nail on the head in his Daniel Hertz youtube talks about using science properly to evaluate hi-fi sound. Measurements along don't cut it. This amp measures great but listening to music through it is definitely not at all like experiencing the sound of live classical or popular music to me.

Save up and get a Sparkos Gemini for your headphones and buy a separate pre-amp of your liking.
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