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SMSL SH-8S Review (headphone amplifier)

amirm

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This is a review and detailed measurements of the SMSL SH-8S. It was kindly drop shipped to me from SMSL by ShenzhenAudio. Unfortunately I do not have price or availability. As soon as I find out, I will update the review.

EDIT: the price for this will be US $229.99 and ship date is June 10th, 2021.

I don't know how many colors the SH-8S comes in. The silver one looks fine but made it hard to read the labels:

SMSL SH-8S review headphone amplifier balanced.jpg


As you will see later in the measurements, the XLR output is for convenience and does not produce more power. There are balanced inputs however which I like:

SMSL SH-8S review headphone amplifier balanced input.jpg


Inclusion of mains power supply is a nice touch as it eliminates desk clutter.

Good to see regulatory certification on the back.

Note that you only have low and high gains. No medium.

SMSL SH-8S Measurements
I configured my unit with XLR input and tested with both 1/4 and XLR outputs. Results were identical. Here is the XLR one:

SMSL SH-8S Measurements XLR.png


This is exceptional performance and lands the SH-8S at the top of the chart with its competitors:
best headphone amp review 2021.png


This is one quiet unit with superb dynamic range:

Most quiet headphone amp.png


As such it should very much be suitable to ultra sensitive IEMs.

Frequency response is ruler flat well beyond what we need for audio:

SMSL SH-8S frequency response Measurements XLR.png


Performance as stated is exceptional in low gain mode but high gives up a bit of that:
SMSL SH-8S Measurements XLR Balanced 300 ohm power.png


Still, plenty of power available at 300 ohm. To show that there is no difference between output headphone jacks, here is the comparison:

SMSL SH-8S Measurements XLR unbalanced Balanced 300 ohm power.png


Low gain remains excellent at 32 ohm but high gain slides a bit more competitively:

SMSL SH-8S Measurements XLR Balanced 32 ohm power.png


There is essentially no load dependency other than drop in output voltage as impedance get lower:

SMSL SH-8S SNR Measurements XLR Distortion vs Power vs Impedance.png


Channel balance is excellent for an analog volume control but the unit you buy may be very different:
SMSL SH-8S Measurements XLR headphone amp channel balance.png


SMSL SH-8S Headphone Listening Tests
I will make this short: with both my Sennheiser HD-650 and Ether CX headphone, there was a ton of power available even in low gain mode. High gain had ample headroom well beyond what I would dare to play. There was no distortion I could attribute to the amplifier. Excellent performance all around.

Conclusions
We had a DAC race start a couple of years ago to get perfection. We are now well into headphone amplifier perfection gain, with one instrument grade amplifier after another. Each has a different form factor, pricing, and availability though so having options is good. Such is the story of SH-8S. Superb measured and subjective performance.

It is my pleasure to put the SMSL SH-8S on my recommended list.

Note: this is a brand new product. Some headphone amps have had teething issues when released. If you are worried about such things, let others go before you and get some data on reliability.

------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
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Loathecliff

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Vovgan

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I will make this short... Excellent performance all around.

Please try spending more time on products promising this level of performance. It will surely make your life much easier (no need to argue with diehards whether this or that slight imperfection is audible / significant / relevant etc), and it is ultimately the kind of product reviews we the audience crave to see to go and buy new stuff with confidence. Spectacular failures by hyped brands is surely another exciting category but everything in between not so much already.

Looking forward to see Trinnov tested and would really love to see your take on some most promising subs (RELs, SVSs of the world etc).

Thanks!
 

xema

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phoenixsong

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Looks like a direct A30pro competitor with *slightly (edit: much) less max power on high gain. Curious to see the gain values like solderdude, especially since it only has 2 gain settings
 

liu

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Looks like a direct A30pro competitor with *slightly (edit: much) less max power on high gain. Curious to see the gain values like solderdude, especially since it only has 2 gain settings
extra power isn't very useful/practical. you rarely need that much power in real world scenarios. Topping's high number is just for show purposes.
having that much power not only wastes energy (because of quiescent current) and cause global warming, but also makes normal listening difficult --- one need to adjust knob to super low, so very small range of knob is actually used (could cause channel imbalance as well). You only know this when you actually own one of topping's devices such as the A30Pro --- it runs very warm, and volume adjustment in high gain is cumbersome. reading the numbers actually tell nothing about user experience.
 

phoenixsong

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extra power isn't very useful/practical. you rarely need that much power in real world scenarios. Topping's high number is just for show purposes.
having that much power not only wastes energy (because of quiescent current) and cause global warming, but also makes normal listening difficult --- one need to adjust knob to super low, so very small range of knob is actually used (could cause channel imbalance as well). You only know this when you actually own one of topping's device --- it runs very warm, and volume adjustment is cumbersome.
I didn't comment on whether it's useful/critical or otherwise though :p
The gain settings (and price) may be a deciding factor for me since I tend to listen at low volume levels and have sensitive stuff to drive
 

Jimbob54

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Naughty teasing issues at the end of the review.
 

solderdude

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Topping's high number is just for show purposes.

Nope, the idea behind the A30Pro is not about more power and waisting energy at all. It is about having enough output voltage available for certain high impedance headphones that will only work with TRS plugs such as the Beyerdynamic 600 Ohm series in order to drive it so 120dBSPL peaks can be reached.
The higher gain (+14dB) can even be beneficial when applying EQ.

I would agree in practice 800mW in 300ohm will never be used nor do I know of high impedance headphones rated that high in continuous power.

The SMSL seems like a viable option when high gain is indeed high gain. I would expect at least 15dB gain difference based on the measurements.
 
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liu

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I didn't comment on whether it's useful/critical or otherwise though :p
The gain settings (and price) may be a deciding factor for me since I tend to listen at low volume levels and have sensitive stuff to drive
amir may be able to tell the number. based on whats available here the performance sounds very like topping a90 so I guess it's a 0db for low gain and 9.5db for high gain. I may be wrong though.

yes for IEMs topping's low gain on A90 Pro and A30 Pro clearly wins
 

respice finem

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SOT: A standard option to mount headphone amps, DACs and such under the desk (or under the top shelf of a sideboard) would be nice to have. Any DIY mount is mostly useless when changing the gear. Another nice thing would be, the headphone amp would not have to be held in place when plugging/unplugging the headphone jack.
 
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amirm

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How much gain is there in each setting ?
I only know the low gain which is 0 dB. I will measure high gain tomorrow and report back.
 
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amirm

amirm

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Glad to see SMSL learned Topping's design (a tear down could easily reveal that) and make even better products.
though it's a pity that this one does not include relay based volume control.
Relay based volume would probably double its price.
 

Nango

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Unfortunately I do not have price or availability. As soon as I find out, I will update the review.

Needless to say, it's price will depend on the outcome of this review. It's logical. Thanks ASR, won't be cheap. I guess at the lower 400's $ range/around 400 €.
 
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solderdude

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I only know the low gain which is 0 dB. I will measure high gain tomorrow and report back.

Given the 16dB reduction in measured S/N ratio I would expect high gain to be in the +14 to +15dB range.
 

Koeitje

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The connector on the front isn't straight, it triggers me. Hopefully they will have better QC.
 
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