Comfort and specifications
Daily use
As expected, the SMSL HO100 is extremely simple to use. Plug the power cable, connect your DAC or source through the RCA/XLR outputs, attach a headphone and you’re good to go!
You only get two headphone outputs here, contrary to the HiFiman EF-400 which offers no less than four different outputs, to avoid the use of an adapter. That said, the 6.35mm and 4.4mm should be enough for 90% of us, and if you ever need to use a different type of plugs, brands like ddHiFi offer a wide range of adapters/solutions.
Once paired with a good source, in my case the SMSL DO100, the HO100 behaved like any other headphone amp. You turn the volume up/down thanks to the potentiometer, and if you feel like you need more power, you just have to switch it into high-gain mode.
Once again, I really like the potentiometer and it was easy to find the right volume, even with complicated headphones like the Audeze LCD-X. It’s a smooth one, with a long travel course and no channel imbalance, a very nice surprise!
Power and drive
It comes as no surprise, the SMSL HO100 is, hand down, one of the most powerful amps available in this size and range.
I paired it with various headphones and IEMs, ranging from the mighty Sennheiser HD800S, my faithful Audeze LCD-X, or Meze’s mighty Empyrean. None gave the amp a hard time.
If you really need more power, you could take the HO200, but only do so if you want more sound than more power.
Specifications
Fully balanced design
SMSL promised us “ultra-compact design, high power output” and if you read the specs sheets, it looks like the SMSL HO100 delivers. Output power is rated at 3000mW with a 16ohm charge, 1500mW at 32ohm, and 100mW at 600ohm – so about half the HO200 power, which is more than enough on a regular basis.
But, what’s even more impressive are THD numbers. With a 32ohm Load, the SMSL HO100 harmonic distortion reaches an abysmal level (0.00006%) while maintaining a high signal-to-noise ratio (-134dB). Sure, that’s not as good as the HO200, topping at 140dB, but that’s plenty enough for anyone using 24bit/48khz files
Yet, the “piece of resistance” remains the fully-balanced circuitry. I didn’t open the amp, but from the official pics, you can easily see how clean the build is: blackboard, symmetrical op-amp, and Mosfet, perfectly aligned and ready to work.
With an ultra-low distortion precision linear feedback circuit, a custom ultra-low noise power supply, and Texas Instruments OP-Amp, the amp is advertised as “noiseless, or almost” with an output noise just shy of 1.3uV. For comparison, my Cayin iHA-6 should be three-time noisier, and I already have trouble hearing those artifacts.
Last but not least, SMSL gave us some measurements and if I couldn’t do the same, RMS Level and scope are always interesting to look at, from an objective point of view. A-Weighted, the HO100 reaches 4.9Vrms per channel, with 0.00006% THD+N ratio.
For the nerdiest one, here are the graphs and full technical data, for the rest, you can go to the next page already.
Technical Data
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- Model: SMSL HO100
- Type: Headphone Amp
- Outputs: Jack 6.35mm (single-ended) / 4.4mm Pentaconn (balanced)
- Inputs: RCA / XLR
- THD: 0.00006% (-123dB)
- SNR: > 134dB
- Output impedance: near 0 ohms
- Input impedance: 47kohms
- Gain: Low (-9.5dB) / Mid (0dB) / High (15.5dB)
- Output power: 3000mWx2 (16ohm) / 1500mWx2 (32ohm) / 200mWx2 (300ohm) / 100mWx2 (600ohm)
- Size : 150 x 128 x 39 mm
- Weight : 560g
- Power Consumption: 30W
- Price: $149
The review continues on Page Four, after the click HERE or by using the jump below.
