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Sabaj A10h Review (Headphone Amplifier)

amirm

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This is a review and detailed measurements of the Sabaj A10h headphone amplifier. It was sent to me by the company and cots US $120 on Amazon including Prime shipping.

Note: without asking, the company made a generous donation to the forum prior to this review. As you can imagine, such can't change the nature of my testing as most are objective and identical to others. It did however made me guilty to finally test this amplifier after it was sitting for some two months here. :) But if you like to read some form of bias into this review, you are welcome to do so.

The A10h distinguishes itself from others in its price range in two ways starting with a digital display of the volume:

Sabaj A10h Review Headphone Amplifier.jpg


And secondly by stepped relay volume control which should translate into great channel matching. Usually such volume controls are reserved for higher priced amplifiers.

While I appreciate the channel matching such controls provide, I don't like the slow operation in some and especially when they cause glitches as they change volume. Neither was the case here! Volume control is fast and I could not detect much if any glitching. So all the benefits of analog volume control without its drawbacks.

Edit: forgot to mention that digital volume control means that you can also use a remote which comes with the A10h making it nice for controlling a main stereo system.

Changing gain and whether the headphone is on or off is done by pushing the volume control in and rotating. This is a bit slower than having flip switches but it is implemented well enough that it is pretty fast to use. No indication however on the current setting.

Power is provided as usual by a medium sized external switching power supply:

Sabaj A10h Review back panel Headphone Amplifier.jpg


A figure 8 power cord is provided.

As you see, there is only unbalanced RCA in and 1/4 unbalanced headphone out. Makes my work a lot easier but you could be subject to ground loops as compared to a higher end unit with XLR balanced inputs. More on this in a bit.

Sabaj A10h Measurements
As usual we start with our dashboard. For unbalanced devices, I feed them 2 volts and use the lowest gain that allows 2 volts out. In this case, that was the "h1" gain setting (there is Low, H1 and H2):

Sabaj A10h Measurements Headphone Amplifier.png


Company shows 120+ dB SINAD but that is with 5 volts out which I could also match. But again, to create a level playing field, I only go to 2 volts on unbalanced headphone amplifiers.

Performance here ranks near top of the class:

Best headphone amplifier tested 2021.png


I have seen member Wolf measuring this amplifier and scoffing at lower SINAD he got as a result of mains noise and harmonics. When I first measured the A10h, I saw the same thing but as is always my procedure, I play with various grounding modes to see if it is specific to my setup or nature of the device itself. The unbalanced Audio Precision outputs and inputs are "floating" meaning they are not ground referenced. This is normally good in that it reduces the chances of ground loops but sometimes, it works the other way around, causing such interference. Such was the case here. As soon as I connected the AP ground to the RCA shield, it substantially reduces mains interference resulting in the above measurement.

Note also that I use my new Neurochrome HP-LOAD headphone amplifier load which always runs in differential mode even when measuring non-balanced loads as is the case here. So don't be alarmed or confused when you see "Analog Balanced" at the bottom of the dashboard.

The A10h as measured easily clears threshold of hearing as far as noise and distortion so transparency is guaranteed.

Next up is signal to noise ratio/dynamic range both at unity gain (2 volts in/out) and 50 mv out:

Sabaj A10h Dynamic Range Measurements Headphone Amplifier.png


We are just a few dBs short of class leading gear but still, very good results:

Most quiet headphone amplifier for IEMs.png


Frequency response was ruler flat which is excellent:

Sabaj A10h Frequency Response Measurements Headphone Amplifier.png


Multitone shows exceptionally low distortion:

Sabaj A10h Measurements Multitone Headphone Amplifier.png


Seems that the unit is designed to accept more than 2 volt input as with this being the limit, it never clips:

Sabaj A10h Measurements Power into 300 ohm Headphone Amplifier.png


Sabaj A10h Measurements Power into 32 ohm Headphone Amplifier.png


It is so even as I push the load way down to speaker levels!

Sabaj A10h Measurements Power versus distortion Headphone Amplifier.png


As expected, channel matching is perfect:

Sabaj A10h Measurements channel matching Headphone Amplifier.png


So if you are an IEM listener or one with sensitive headphones, you will enjoy perfect matching to as low a volume as you want to listen.

Sabaj A10h Listening Tests
I started listening with my Sennheiser HD650 headphones using H2 gain level. There was incredible amount of power available with deep bass notes easily rattling my ears in the second or two that I pushed the volume near max. Normal listening levels showed plenty of headroom. Detail, clarity, etc. was all top class as expected. I could detect no limitations or aberrations attributable to the A10h.

Switching to Drop Ether CX headphones, I had to push the volume near max for very loud listening but otherwise, I again could not detect any rise in distortion, etc. The sound was as clean as the headphone could deliver.

As I noted in the intro, it was a delight to be able to change the volume quickly and without annoying glitches.

Conclusions
The Sabaj A10h not only delivers top marks as far as performance, but innovates in bringing a very responsive stepped relay in this super low price category. Subjective performance both from sound and usability is quite good winning me over as a fan.

I am happy to recommend the Sabaj A10h headphone amplifier.

-----------
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/
 
Last edited:

enricoclaudio

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Nice review, @amirm as always. I think you forgot to mention that it comes with an IR remote ;)
 
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amirm

amirm

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enricoclaudio

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jtwrace

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It did however made me guilty to finally test this amplifier after it was sitting for some two months here.
I thought it sitting there was required for break in!?! :p
 

Matias

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Wow impressive, specially the stepped relay volume control in this price category.
 

vkvedam

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Brilliant! Kudos to Sabaj on making a generous donation as well irrespective of the outcome :)
 

Aperiodic

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Output impedance (or did I miss it)? I see the specs above but... "Trust but verify".
Donation by the company is a nice gesture. People should consider doing likewise when they send things in. Why should Amir have to pay to review our equipment? This reminds me to send a donation today to defray return shipping for my Beyer Amiron headphones which are (according to USPS anyway) out there in the queue somewhere, awaiting testing.
 
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amirm

amirm

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119mw @300 Ohm kind of low?
My requirement is 100 milliwatts which it provides. From experience, this is plenty of power for likes of Sennheiser HD650 and such as subjective testing showed. Of course, more is available in other products but they cost more as well.
 
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amirm

amirm

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Output impedance (or did I miss it)? I see the specs above but... "Trust but verify".
It is rare these days to find a high impedance headphone amp so I don't always measure it if there is plenty of power at 32 ohm. If impedance is high, that power gets lost internally.
 
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