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Topping L50 Review (Headphone Amp)

amirm

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This is a review and detailed measurements of the new Topping L50 balanced (input) headphone amplifier. It was sent to me by the company and costs US $229. It will be announced shortly.

The industrial design of the L50 is different than older models with a plexiglass front:

Topping L50 Review Balanced Headphone Amplifier.jpg


While I like the red accent on the volume control knob, the contrast is low on the labels to read them easily. There is a plastic cover that has duplicate labels on it which are more legible. Fortunately there is not a whole lot here to remember as to need the labels.

The back side and power supply show more of a departure:
Topping L50 Review back panel Balanced Headphone Amplifier.jpg


Instead of the usual switching power supply we now have a beefy AC transformer. As I have noted before, AC input makes it easier to generate positive and negative rails for the amplifier so I can see the motivation. Then again, the transformer is inefficient and quite large.

Up on top you see a connector you don't normally see on a pure analog amplifier: the USB-C for firmware upgrades! A supervisory processor handles protection which can be reprogrammed as needed. Indeed, during testing I pushed the unit hard with 12 ohm load well into clipping and it shut down with a sequence of LED lights. Once it cooled a bit, it enabled the device to function again.

The other change which we have seen recently from Topping is use of 1/4 inch input for balanced interconnections. They take up a lot less space than XLR so you can have the same rich set of connectivity including pre-amp in this small enclosure. 1/4 balanced is extremely popular in pro audio so there is plenty of cables and adapters for it if you are not situated currently to use them. And I believe a set of adapters come with the unit.

Topping L50 Measurements
There are many combinations here to test so I limited the input to balanced but measured both balanced and unbalanced headphone output. Let's start with balanced input:

Topping L50 Measurements Balanced Headphone Amplifier.png


And now RCA In:

Topping L50 Measurements Unbalanced Headphone Amplifier.png


Exceptional performance yet again, almost in the top position of our rankings for SINAD:

best headphone amp reviewed balanced.png


Here are our noise specs which are stellar:

Topping L50 Measurements Balanced SNR Headphone Amplifier.png


This is what great SINAD does for you at the top of the class: incredibly low noise where you need it with sensitive IEMs:

most quiet headpone amp reviewed.png


Anyone who says SINAD is not important doesn't understand this dynamic, pun intended.

Frequency response is flat of course to beyond what we need:

Topping L50 Measurements Frequency Response Balanced Headphone Amplifier.png


The main business of a headphone amp is producing power though to drive more difficult headphones. So let's test that with 300 ohm load:
Topping L50 Measurements Power into 300 ohm Balanced Headphone Amplifier.png


My standard for power output is 100 milliwatts and the L50 sails way past that which is great.

Let's switch to other extreme with 32 ohm load, emphasizing current delivery as opposed to voltage:

Topping L50 Measurements Power into 32 ohm Balanced Headphone Amplifier.png


This is a ton of power coming out of this little box.

Sweeping the load and measuring power we get:
Topping L50 Measurements distortion vs power vs impedance Balanced Headphone Amplifier.png


The main difference here compared to bigger brothers is that it clips with higher impedances whereas they don't. Up to nearly 7 volts there is no load dependency.

Finally here is our channel matching which is excellent for an analog control:
Topping L50 Measurements Channel Matching Headphone Amplifier.png


As usual your mileage may vary.

Listening Tests
Surprise, surprise, the L50 aces my subjective tests. What can I say. Whether I used the Sennheiser HD650 or Drop Ether CX, there was incredibly clarity, detail, authoritative bass, etc. My ears would scream before the amplifier even got barely unhappy as far as volume.

Conclusions
Hit after hit is the expression that always comes to mind when testing Topping products. Engineering done properly would be another saying. Compare this to many high-end products which barely get verified at all to see if they are what they think they are (transparent and well engineered). We do have some departure in form factor and functionality most of which are positive in my view. You get more choices and more to decide. :)

It is my pleasure to recommend the Topping L50.

Note: I have no commercial connection of any sort of shape with Topping or any other company for that matter. Don't spread rumors otherwise or I will personally show up and whack you in the back of the head! :) Many companies send me products and when they perform this well, they get my accolades.

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LearningToSmile

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Stellar measurements, but I have some questions about functionality - can the pass through be turned off in any way or is it always on? And if it's always on is it in line out mode at full volume, or in pre-out mode controlled by the volume knob?
 
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amirm

amirm

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There is no switch to turn off the pre outs so they are pass-through. The manual has a typo but I think the pass through goes off when you turn off the L50.
 

keebz28

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@amirm Wow what a stupendous performer. Btw i love the last sentence of the review where you're laying down the law about rumor mongers!
 

L-Train

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This looks incredible! The feature set looks identical to that of the A30Pro but at a more reasonable price. I was eyeing the A30Pro for a while now but I'm very tempted to buy this over it.

Interesting about the increase in noise going from XLR in -> 1/4" out. I wonder what could be the cause of that. I assume medium gain on the L50 is unity and the AP was outputting 2Vrms over XLR? In comparison, the A30Pro going from XLR in -> 1/4" out doesn't show an increase in noise, though that was tested with 4V instead of 2V.
 
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amirm

amirm

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Interesting about the increase in noise going from XLR in -> 1/4" out. I wonder what could be the cause of that.
It is the benefit of differential output. Voltage doubles but noise scales half as much.
 

L-Train

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It is the benefit of differential output. Voltage doubles but noise scales half as much.
Interesting, the A90 also has differential output but doesn't show an increase in noise from XLR in -> 1/4" out. The L50 must have different approach/implementation to this, but is understandable given the form factor. At any rate, this thing looks like a winner!
 

usern

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Is there any noise coming from the unit if power is plugged in, but front switch is at off position? A30pro has faint buzz in this condition which can be heard in a very quiet room.
 
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amirm

amirm

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Interesting, the A90 also has differential output but doesn't show an increase in noise from XLR in -> 1/4" out.
That was a more complicated and corner case in that volume had to be adjusted for balance out and that added a bit of noise. What I show here is the rule.
 
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amirm

amirm

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Is there any noise coming from the unit if power is plugged in, but front switch is at off position? A30pro has faint buzz in this condition which can be heard in a very quiet room.
I can't think of anything making noise in this device seeing how the transformer is external. But it is not something I checked. When I back at my bench, I will test.
 

sarumbear

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Is there any noise coming from the unit if power is plugged in, but front switch is at off position? A30pro has faint buzz in this condition which can be heard in a very quiet room.
Could it be possible that the switch opens the output circuit and with no termination your amplifier is magnifying parasitic noise? Similar to plugging in an unterminated cable.
 

Chilli

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I saw they were going to release these when I saw a FB post the other day. Such a pity they measure so damn well. I just bought a Sabaj a10h!
Well done again Topping. Balanced in and out in such a compact vessel. Good work.
Wish you would consider the AV market as well, but I can see that can be quite a big step, with things like hdmi and fees etc. But have you seen the gap in the market when you have Apple TV with only an hdmi output but limited to 48k
 

keebz28

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They just keep “Topping” the ASR Charts for performance and value.

Badam Tish. I think your job is done here for the night sir. See yourself out. (laughing).:)
 

Jimster480

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Wow, what an amazing value! This even beats the THX 789 and its only $229. Then again I bought my THX 789 years ago for like $275 in super early bird so I cannot complain.

Overall it seems that while other things go down the tubes; Topping is still kicking butt and taking names.
 
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