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Matrix Audio HPA-3B Balanced Headphone Amp Review

amirm

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#1
This is a review and detailed measurements of the Matrix Audio HPA-3B Balanced (input and output) headphone amplifier. It is on kind loan from a member. Even though the HPA-3B still a current product, I can't find a reliable price for it. Seems to have gone for less than US $500 and came out in 2017 I think. [edit: it came out in 2015]

Like the HPA-3U, the HPA-3B comes in a beefy and very deep enclosure:
Matrix Audio HPA-3B Balaneced Headphone Amplifier Review.jpg

The volume control is a bit stiff and slippery for my taste.

The gain control is in the back unfortunately:
Matrix Audio HPA-3B Balaneced Headphone Back Connectors Amplifier Review.jpg

Inclusion of AC mains power supply though is very nice in the way it declutters your desk.

Note that unlike the HPA-3U, there is no DAC in this unit. Nor is there any RCA inputs. The latter can be easily solved though with an XLR to RCA cable while giving you most of the benefits of balanced input and its mains noise immunity.

Headphone Amplifier Measurements
Here is our usual dashboard:
Matrix Audio HPA-3B XLR In TRS Out Audio Measurements.png


Distortion is vanishingly small. THD+N and hence SINAD score is dominated by the power supply/mains noise at multiples of 60 Hz. Since our hearing sensitivity is poor in low frequencies, the SINAD score underestimates the good performance of HPA-3B. Rules are rules though and we have to go with the number we have in our rankings:

Best Headphone Amplifier Review 2019.png


Signal to noise ratio as well is impacted by the power supply noise:

Matrix Audio HPA-3B XLR In TRS Out SNR Audio Measurements.png


Most quiet headphone amplifier.png


Frequency response is a bit less extended than I like:
Matrix Audio HPA-3B XLR In TRS Out Frequency Response Audio Measurements.png


Power into 300 and 33 ohm loads show the HPA-3B to have very strong drive, capable of driving just about any headphone:

Matrix Audio HPA-3B XLR In TRS Out Power into 300 Ohm Audio Measurements.png


Matrix Audio HPA-3B XLR In TRS Out Power into 33 Ohm Audio Measurements.png


As good as these numbers are, when you use the XLR "balanced" headphone output, you get lot more power still:

Matrix Audio HPA-3B XLR In TRS Out Power into 50 Ohm balanced Audio Measurements.png


I have revised the channel balance measurement with two cut off points:
Matrix Audio HPA-3B XLR In XLR Out Channel Balance Audio Measurements.png


So depending how much attenuation you need, you may or may not experience channel balance issues.

Output impedance is comfortably low at 1.2 ohm:
Lowest Headphone Output Impedance.png



Listening Tests
Sorry, did not have a balanced DAC handy to test the HPA-3B. I suspect it will perform very well though given its power and similarity to HPA-3U.

Conclusions
The world of headphone amplifiers has been turned upside down with a number of superlative units in the last 12 to 16 months. Prior to that, the HPA-3B would have been the king. Still, what is there has extremely low distortion and lots of power. Assuming you get it for a better price than $500, it makes a good option. As such, I can recommend it.

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

Have you heard of pink panthers skiing? Me neither. It is snowing at the summit near us and panther saw that on TV and want to go and try it! Even renting the gear for them will be expensive let alone classes they need to take. So I implore you to open your wallet and donate generously account using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Amir
 
Last edited:

maxxevv

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#3
Would a proper functioning mains filter have helped in overall noise readings ?

That is a tremendous amount of power.

I have the unit. The only grouse I have with it really is the heat it generates. Its almost like a tube amp in how much heat it emits after about an hour of use. Other than that, the power is just so addictively effortless.

Thanks for the review. Its definitely a keeper !
 

amirm

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#4
No, mains conditioning cannot help. Power is generated at 60 Hz. You surely don't want to filter that out as you have no power then. :) This is likely internally induced from the power supply. External switching power supply is a hassle but usually doesn't have this problem.
 

maxxevv

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#5
Just to add, the Amp can run with a non-XLR input. They included XLR > RCA adaptors.

I run it with my Khadas Tone Board just fine.


There have been subjective reviews of the HPA-3B saying some shielding of the toroidal transformer with Nu-metal or similar EMF absorbtion plates from the rest of the close-by circuitry helps. That of course is completely subjective, I have not seen measurements that actually show the differences. But certainly would like to explore them if I can.
 

trl

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#7
No, mains conditioning cannot help. Power is generated at 60 Hz. You surely don't want to filter that out as you have no power then. :) This is likely internally induced from the power supply. External switching power supply is a hassle but usually doesn't have this problem.
Like @bunkbail already stated, shielding the trafo will remove entire mains hum.
As for the "Frequency response is a bit less extended than I like", the low-pass filter can be easily adjusted by replacing the 4 SMD resistors with higher values ones.
I also recommend swapping the 4 x 2.2uF input caps with 4 x 4.7uF caps, to get the freq. response line perfectly flat. :)
BTW, this headamp comes with two RCA-XLR connectors, so we can connect it to a non-balanced DAC with ease.
 

trl

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#8
Worth adding that swapping the default LME49860 with OPA1652 the background noise will decrease a bit. Just double check opamp temperatures and, if needed, use some thermal double-tape and stick couple of heat-sinks on top.
 

dmac6419

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#11
This is a review and detailed measurements of the Matrix Audio HPA-3B Balanced (input and output) headphone amplifier. It is on kind loan from a member. Even though the HPA-3B still a current product, I can't find a reliable price for it. Seems to have gone for less than US $500 and came out in 2017 I think.

Like the HPA-3U, the HPA-3B comes in a beefy and very deep enclosure:

The volume control is a bit stiff and slippery for my taste.

The gain control is in the back unfortunately:

Inclusion of AC mains power supply though is very nice in the way it declutters your desk.

Note that unlike the HPA-3U, there is no DAC in this unit. Nor is there any RCA inputs. The latter can be easily solved though with an XLR to RCA cable while giving you most of the benefits of balanced input and its mains noise immunity.

Headphone Amplifier Measurements
Here is our usual dashboard:
View attachment 41338

Distortion is vanishingly small. THD+N and hence SINAD score is dominated by the power supply/mains noise at multiples of 60 Hz. Since our hearing sensitivity is poor in low frequencies, the SINAD score underestimates the good performance of HPA-3B. Rules are rules though and we have to go with the number we have in our rankings:

View attachment 41339

Signal to noise ratio as well is impacted by the power supply noise:

View attachment 41340

View attachment 41341

Frequency response is a bit less extended than I like:
View attachment 41342

Power into 300 and 33 ohm loads show the HPA-3B to have very strong drive, capable of driving just about any headphone:

View attachment 41343

View attachment 41344

As good as these numbers are, when you use the XLR "balanced" headphone output, you get lot more power still:

View attachment 41345

I have revised the channel balance measurement with two cut off points:
View attachment 41346

So depending how much attenuation you need, you may or may not experience channel balance issues.

Output impedance is comfortably low at 1.2 ohm:
View attachment 41347


Listening Tests
Sorry, did not have a balanced DAC handy to test the HPA-3B. I suspect it will perform very well though given its power and similarity to HPA-3U.

Conclusions
The world of headphone amplifiers has been turned upside down with a number of superlative units in the last 12 to 16 months. Prior to that, the HPA-3B would have been the king. Still, what is there has extremely low distortion and lots of power. Assuming you get it for a better price than $500, it makes a good option. As such, I can recommend it.

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

Have you heard of pink panthers skiing? Me neither. It is snowing at the summit near us and panther saw that on TV and want to go and try it! Even renting the gear for them will be expensive let alone classes they need to take. So I implore you to open your wallet and donate generously account using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Amir
https://apos.audio/products/matrix-...JJxyIpayAo04tatGrpsf6FtiGee1VFNUaAl77EALw_wcB
 

abvolt

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#12
I was once interested in the matrix x sabre dac a number of years ago and could never get my hands on one here in the US, same thing with the HPA-3B I've looked guess they don't want to sell much of their gear..
 

Tks

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#15
Look how small this thing is, and look at the insane power output. Matrix was killing it even back in 2015.
 

maxxevv

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#16
Look how small this thing is, and look at the insane power output. Matrix was killing it even back in 2015.
It actually has a pretty big footprint on the desk as its quite long (depth wise, which the picts here don't quite show). Not the easiest of components to place nicely in a stack either. Especially when you consider how much heat it ejects after an hour or more of use.
 

trl

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#17
I am waiting for @MatrixAudio to get a new HPA-3B on market, but a bit modified, if possible:
- between transformer and analogue XLR traces there needs to be a shield placed (GOSS or Mu Metal) to lower the mains hum;
- low pass filter should be less restrictive (4 resistors values should get modified);
- high pass filter should be less restrictive too (the 4 input caps should be increased to 4.7uF);
- voltage rails should get lowered to 2x15V, to decrease internal temps and to limit output power as well (or swap SMD components to THT, like the Deckard version, at least the 16 transistors and the 8 output resistors that gets brownies when pushing the amp to the limit);
- use shielded cable from XLR to the ALPS pot instead of PCB traces (or do a ground plane around these traces).

By doing the above will lower the hum and background noise, hence SINAD will get even higher.

Thank you!
 
Last edited:

MatrixAudio

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#18
I am waiting for @MatrixAudio to get a new HPA-3B on market, but a bit modified, if possible:
- between transformer and analogue XLR traces there needs to be a shield placed (GOSS or Mu Metal) to lower the mains hum;
- low pass filter should be less restrictive (4 resistors values should get modified);
- high pass filter should be less restrictive too (the 4 input caps should be increased to 4.7uF);
- voltage rails should get lowered to 2x15V, to decrease internal temps and to limit output power as well (or swap SMD components to THT, like the Deckard version, at least the 16 transistors and the 8 output resistors that gets brownies when pushing the amp to the limit);
- use shielded cable from XLR to the ALPA pot instead of PCB traces (or do a ground plane around these traces).

By doing the above will lower the hum and background noise, hence SINAD will get even higher.

Thank you!
Got it, if we will do new headphones amp, we will consider you advises.
Thank you!
 

Tks

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#19
It actually has a pretty big footprint on the desk as its quite long (depth wise, which the picts here don't quite show). Not the easiest of components to place nicely in a stack either. Especially when you consider how much heat it ejects after an hour or more of use.
Bu but.. It's winter here, that's perfect! :p
 

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