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Burson Soloist 3XP Review (Headphone Amp)

Rate this headphone amplifier:

  • 1. Poor (headless panther)

    Votes: 150 65.5%
  • 2. Not terrible (postman panther)

    Votes: 65 28.4%
  • 3. Fine (happy panther

    Votes: 5 2.2%
  • 4. Great (golfing panther)

    Votes: 9 3.9%

  • Total voters
    229

amirm

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This is a review and detailed measurements of the Burson Soloist 3X Performance balanced headphone amplifier. It is on kind loan from a member and costs US $1,200.
Burson 3X Performance Review JRC5532 Opamp balanced 3XP Stereo Headphone Amplifier.jpg


The overall package feels heavy and solid but I am not a fan of lack alignment of all the connectors, holes, etc. Volume control is digital but controls a Muse IC volume control. The microprocessor managing it is very fast and responsive but alas, there is no acceleration. If the volume is too loud -- which can very well be with this powerful amp -- good luck in turning it down quickly! We are talking many turns to go from 99 to zero. Very strange how many companies miss implementing this useful feature.

Back to volume control, there is a glitch between volume level 35 and 36. It is a minor tick but otherwise it is silent as it adjusts its volume.

A switch on the right puts you in the menu. Navigating the few items in there is very difficult as now the volume control goes up and down in the list and pushing it selects the item. Well, as you push it, it can rotate a bit and change some other item. Worst part of this is that the gain setting is here and switching that from low to medium and high is very tedious. I really wish there was a button for this in the front panel. It is not like it would make it any more messy than it is now.

The rear connections are as you would expect:
Burson 3X Performance Review JRC5532 Vivid Opamp balanced 3XP Stereo Headphone Amplifier.jpg


I was yet disappointed to see no marking on of which channel is which with XLR connections.

As you see power is provided by a laptop sized switching supply pumping out 24 volts at 3 amps which means there is 75 watts on top here. Why does it need so much power? Because it is a small power amplifier:

Burson 3X Performance Review JRC5532 Vivid Opamp rolling teardown balanced 3XP Stereo Headphon...jpg


Companies is famous for encouraging "opamp rolling" meaning replacing a pair of op-amps with discrete ones. To have a baseline, I went to the non-glamorous JRC5532. Owner had shipped this with Sparkos and Vivid op-amps. What was supposed to be an easy process was a nightmare. The supplied sockets have large round holes that are too large for the flat pins of the JRC (and Vivid as owner told me). You have to mess with the pins to get them to insert while putting enough side pressure to the pins. If you don't do this, you get partial connection and an unhappy unit. Despite my best effort that took some half hour, I still don't like the results. If you are going to provide replaceability you better make sure the job is doable.

Swapping the opamps requires resetting DC offset using the 4 pots that are undocumented. Google search indicated such a functionality. I found one channel close to zero but the other with 45 mv of DC offset. I adjusted both channels to near zero.

Back to power, during the testing the unit got quite warm. Those output transistors dissipate a ton of power which they push into bottom of the unit. They must run very hot in order for the top to get warm as well.

Burson Soloist 3X Performance Measurements
I started testing the unit with the mix of Vivid and Sparkos discrete op-amps as I noted. I was seeing very odd results so decided to do my testing with the JRC opamp as I noted. Alas, the problems were independent of the opamp as you see shortly.

My standardized test for (balanced) headphone amplifiers is to feed them 4 volts over XLR input and use the lowest gain setting+volume control combination that produces the same 4 volts ("unity gain). Low gain was not enough so I went up to medium gain, only to find the performance very poor:

Burson 3X Performance Measurements JRC5532 Opamp Medium Gain balanced 3XP Stereo Headphone Amp...png


I tried the high-gain setting and then turn down the volume and surprisingly, got much better results:

Burson 3X Performance Measurements JRC5532 Opamp High Gain balanced 3XP Stereo Headphone Ampli...png


Cleary there is a problem in the way gain settings are implemented. If I have a more sensitive headphone, I like to take advantage of the lower noise of medium gain. Why penalize me with more distortion then?

Even with high gain, performance is not competitive:
Best balanced headphone amp review.png


Speaking of noise, here is the performance:
Burson 3X Performance Measurements JRC5532 Opamp SNR balanced 3XP Stereo Headphone Amplifier.png


As you see, there is clear penalty for high gain setting.

For 50 mv output, I selected low gain and story got even worse there:

Burson 3X Performance Measurements JRC5532 Opamp Low Gain balanced 3XP Stereo Headphone Amplif...png


I don't know why one channel is so much worse. Such performance squarely lands the 3XP in the poor category of all headphone amps tested:

most quite headphone amp review.png


So the unit is not going to be usable with sensitive IEMs and even headphones.

Oddness continued in frequency response:
Burson 3X Performance Measurements JRC5532 Opamp Frequency Response Medium Gain balanced 3XP S...png


It did the same thing with the other opamps so it is not related to this. Why is one channel response so different than the other?

Power testing using 32 and 300 ohm shows very early rise in distortion indicating low feedback or design error:

Burson 3X Performance Measurements JRC5532 Opamp Power into 32 ohm balanced 3XP Stereo Headpho...png



Burson 3X Performance Measurements JRC5532 Opamp Power into 300 ohm balanced 3XP Stereo Headph...png


The good news though is that you have tons and tons of power. This may be the most powerful headphone amplifier I have tested (above are all balanced output).

Here is the output voltage from which you can compute power at multiple impedances:
Burson 3X Performance Measurements JRC5532 Opamp Power vs load balanced 3XP Stereo Headphone A...png


The best part of the design is perfect channel match courtesy of the Muse volume control IC:
Burson 3X Performance Measurements JRC5532 Opamp Medium Gain Channel Balance balanced 3XP Ster...png


Edit: New measurement for fixed gain mode
Due to higher gain, I had to drop the input to 0.18 volt to get the same 4 volt output as variable gain mode:
Burson 3X Performance Review JRC5532 Opamp Fixed Gain balanced 3XP Stereo Headphone Amplifier.png


This is a 4 to 5 dB reduction in distortion which is nice to see. Noise however is still high:
Burson 3X Performance Review JRC5532 Opamp Fixed Gain SNR balanced 3XP Stereo Headphone Amplif...png


I was please to see the error in frequency disappear in this mode:

Burson 3X Performance Review JRC5532 Opamp Fixed Gain Frequency Response balanced 3XP Stereo H...png


Both power curves show improvements in distortion and overall accuracy:
Burson 3X Performance Review JRC5532 Opamp Fixed Gain Power 300 balanced 3XP Stereo Headphone ...png


Burson 3X Performance Review JRC5532 Opamp Fixed Gain Power 32 balanced 3XP Stereo Headphone A...png


So if you have the option of variable volume in your source/DAC, I highly recommend using that instead of what is built into the 3XP.

Listening Tests
I started testing with my most difficult to drive headphone, the Dan Clark Stealth. In high gain, there was plenty of volume available with loud listening not requiring levels above 75. I then switched to Sennheiser HD650. Naturally there was enough volume there (balanced) to drive you to hearing loss. I tested it in unbalanced mode and here, I could get the amp to distort but this was already way past the point of safe listening. Same was the case with the Drop Ether CX.

I could not put my finger on audible distortion at comfortable listening levels.

Op-amp Rolling
I will do more extensive testing on this later but for now, here is the performance of the unit as it arrived with mix of Sparkos and Vivid op-amps:

Burson 3X Performance Measurements High Gain balanced 3XP Stereo Headphone Amplifier.png


This is basically the same as using JRC op-amp. Sources of noise and distortion are elsewhere.

Conclusions
To borrow a phrase, Burson Soloist 3XP is all power and little fineness. Not objectively anyways. If you have very inefficient headphones, it can provide power that few headphone amplifiers in the market can provide. At anything lower, you can get far better performance for much less money.

I can't recommend the Burson Soloist 3X Performance unless you have a niche application of needing its power.

---------
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:

respice finem

Major Contributor
Joined
Feb 1, 2021
Messages
1,381
Likes
2,448
This is a review and detailed measurements of the Burson Soloist 3X Performance balanced headphone amplifier. It is on kind loan from a member and costs US $1,200.
View attachment 209176

The overall package feels heavy and solid but I am not a fan of lack alignment of all the connectors, holes, etc. Volume control is digital but controls a Muse IC volume control. The microprocessor managing it is very fast and responsive but alas, there is no acceleration. If the volume is too loud -- which can very well be with this powerful amp -- good luck in turning it down quickly! We are talking many turns to go from 99 to zero. Very strange how many companies miss implementing this useful feature.

Back to volume control, there is a glitch between volume level 35 and 36. It is a minor tick but otherwise it is silent as it adjusts its volume.

A switch on the right puts you in the menu. Navigating the few items in there is very difficult as now the volume control goes up and down in the list and pushing it selects the item. Well, as you push it, it can rotate a bit and change some other item. Worst part of this is that the gain setting is here and switching that from low to medium and high is very tedious. I really wish there was a button for this in the front panel. It is not like it would make it any more messy than it is now.

The rear connections are as you would expect:
View attachment 209177

I was yet disappointed to see no marking on of which channel is which with XLR connections.

As you see power is provided by a laptop sized switching supply pumping out 24 volts at 3 amps which means there is 75 watts on top here. Why does it need so much power? Because it is a small power amplifier:

View attachment 209178

Companies is famous for encouraging "opamp rolling" meaning replacing a pair of op-amps with discrete ones. To have a baseline, I went to the non-glamorous JRC5532. Owner had shipped this with Sparkos and Vivid op-amps. What was supposed to be an easy process was a nightmare. The supplied sockets have large round holes that are too large for the flat pins of the JRC (and Vivid as owner told me). You have to mess with the pins to get them to insert while putting enough side pressure to the pins. If you don't do this, you get partial connection and an unhappy unit. Despite my best effort that took some half hour, I still don't like the results. If you are going to provide replaceability you better make sure the job is doable.

Swapping the opamps requires resetting DC offset using the 4 pots that are undocumented. Google search indicated such a functionality. I found one channel close to zero but the other with 45 mv of DC offset. I adjusted both channels to near zero.

Back to power, during the testing the unit got quite warm. Those output transistors dissipate a ton of power which they push into bottom of the unit. They must run very hot in order for the top to get warm as well.

Burson Soloist 3X Performance Measurements
I started testing the unit with the mix of Vivid and Sparkos discrete op-amps as I noted. I was seeing very odd results so decided to do my testing with the JRC opamp as I noted. Alas, the problems were independent of the opamp as you see shortly.

My standardized test for (balanced) headphone amplifiers is to feed them 4 volts over XLR input and use the lowest gain setting+volume control combination that produces the same 4 volts ("unity gain). Low gain was not enough so I went up to medium gain, only to find the performance very poor:

View attachment 209179

I tried the high-gain setting and then turn down the volume and surprisingly, got much better results:

View attachment 209180

Cleary there is a problem in the way gain settings are implemented. If I have a more sensitive headphone, I like to take advantage of the lower noise of medium gain. Why penalize me with more distortion then?

Even with high gain, performance is not competitive:
View attachment 209182

Speaking of noise, here is the performance:
View attachment 209181

As you see, there is clear penalty for high gain setting.

For 50 mv output, I selected low gain and story got even worse there:

View attachment 209183

I don't know why one channel is so much worse. Such performance squarely lands the 3XP in the poor category of all headphone amps tested:

View attachment 209184

So the unit is not going to be usable with sensitive IEMs and even headphones.

Oddness continued in frequency response:
View attachment 209185

It did the same thing with the other opamps so it is not related to this. Why is one channel response so different than the other?

Power testing using 32 and 300 ohm shows very early rise in distortion indicating low feedback or design error:

View attachment 209186


View attachment 209187

The good news though is that you have tons and tons of power. This may be the most powerful headphone amplifier I have tested (above are all balanced output).

Here is the output voltage from which you can compute power at multiple impedances:
View attachment 209188

The best part of the design is perfect channel match courtesy of the Muse volume control IC:
View attachment 209189

Listening Tests
I started testing with my most difficult to drive headphone, the Dan Clark Stealth. In high gain, there was plenty of volume available with loud listening not requiring levels above 75. I then switched to Sennheiser HD650. Naturally there was enough volume there (balanced) to drive you to hearing loss. I tested it in unbalanced mode and here, I could get the amp to distort but this was already way past the point of safe listening. Same was the case with the Drop Ether CX.

I could not put my finger on audible distortion at comfortable listening levels.

Op-amp Rolling
I will do more extensive testing on this later but for now, here is the performance of the unit as it arrived with mix of Sparkos and Vivid op-amps:

View attachment 209190

This is basically the same as using JRC op-amp. Sources of noise and distortion are elsewhere.

Conclusions
To borrow a phrase, Burson Soloist 3XP is all power and little fineness. Not objectively anyways. If you have very inefficient headphones, it can provide power that few headphone amplifiers in the market can provide. At anything lower, you can get far better performance for much less money.

I can't recommend the Burson Soloist 3X Performance unless you have a niche application of needing its power.

---------
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/
Parts graveyards have no luck with measurements, somehow...
Then, the price...
Headless...
 

Funnyjelo

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I have one and I knew the figures must be bad. You can hear the noise with IEM's. Ultimately I was a little.dissapointed because cost wise I felt like it didn't do enough to warrant the price. I have a topping a30 and use it way more now for its cleaner delivery.
Also it's menu and UI is just bad. Really hard to change outputs and gain. Just silly.
 

bobster

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Mis-aligned connectors and no xlr labels on a $1,200 box? Absurd. :rolleyes:
 

Rja4000

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If power is the issue, I wonder if we wouldn't get a better result by using a Topping LA90 instead, wiring the headphones to the speaker outputs... ?
 

Garrincha

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I have one and I knew the figures must be bad. You can hear the noise with IEM's. Ultimately I was a little.dissapointed because cost wise I felt like it didn't do enough to warrant the price. I have a topping a30 and use it way more now for its cleaner delivery.
Also it's menu and UI is just bad. Really hard to change outputs and gain. Just silly.
It looks almost like a paradigm. The more a brand is respected in certain circles and the more the price is up, the harder it fails on the measurements.
 

iamsms

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Always perplexing to see the fixation with class-A amplification which turns the thing into a space heater, yet it has worse performance than a flea-market class-AB car stereo amplifier. I’m pretty sure I have one in the junk pile that would do better.
I wonder if people would have similar level of fixation if it was called class G or something instead of A.
 

ROOSKIE

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I wonder if people would have similar level of fixation if it was called class G or something instead of A.
You mean class POS?

Well, maybe not quite that class but geez it seems awfully close. Due to power, I'm going with not terrible or as I think I will nickname it "naught t"

Oh well, doesn't look cool either.
 

solderdude

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Too bad the input circuit causes such high distortion. Volume control IC ?
Burson-Soloist-3XP-S2.jpg

This is not the type of distortion one would expect from opamps (be them discrete or not).
The output stage distortion is as can be expected from a discrete opamp (with limited open loop gain).
It is very 'tube like' in distortion profile which is generally what audiophools spending over $1k like to see. That and oozes of (generally never used) power reserve.

People buying this should be punished by poor performance at higher listening levels so they have to turn down the volume... :)
 
Last edited:

Tks

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or something from Topping etc., for 1/3 of the price, if you don't need the added functionality of the ADI2.
And better measured performance out of it, if you're still looking for that sort of thing at this point.
 
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