🔷 Topping A50s Headphone Amp

This is the official thread for the Topping A50s

This thread is for discussion and reviews.

  • 4.4mm and 1/4" outputs
  • 2 gain settings
  • 3500mW balanced output

:red_circle: https://apos.audio/products/topping-a50s-headphone-amplifier?sca_ref=36221.ouwJgZltO5

[Reviews]

Z Reviews



People should know that the output power of this amp is almost unachievable in real-life usage. Most DACs have the standard 2Vrms line out voltage but they’ve used way more than that to achieve those numbers.

For Topping L30, they used 9V in mid-gain and 3V in high gain (source). Show me a single dac that have 9V unbalanced. I’m just curious.

I’m not saying A50s is terrible although it’s kinda meh to me.

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I’m guessing this is another SMSL SP200, where it’s “balanced” in name, as there’s no balanced input?

I bought one of these on sale for Black Friday at $170 USD. Was looking for a solid state single ended amp as a secondary amp to connect to my SMSL M500 DAC. I wanted a small form factor, that I could put my Pro-Ject streamer on top of. The A50s is perfect and sounds excellent. Makes the Tin P1’s the best I have heard them.

My only complaint is the tiny volume knob which is too close to the 4.4 jack. Sound wise though this one’s a winner.

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INTRODUCTION

Apos Audio graciously sent me another round of review units, this time the Topping A50s headphone amplifier being one of them. Apos made no attempt to influence my opinion, asking only that I do a fair review. What you are about to read is therefore my opinion and mine alone. The A50s is Topping’s newest entry to their measurement-focused line of headphone amps. It’s causing quite a stir. Is the stir worth it? Read on to find out…

TL;DR

The A50s is a well-built (at least on the outside) amp with a minimal footprint. Despite having only single-ended inputs its balanced topology eliminates ground loop noise. It also has the power to drive most headphones from its balanced output. Yet, its sound is oversmoothed, the bass rolls off below 50 Hz, the soundstaging is flat compared to its similarly priced competition, and it generally falls behind its market rivals in subjective performance for the price.

WAIT, AREN’T WE MAD AT TOPPING?

Topping has been in the audio news lately – such as it is – for inauspicious reasons. I won’t go into details here but you can read about the issue further here. Apos assured me that they had assurances from Topping that the catastrophic, headphone-killing failure that afflicted the L30 is not possible on the A50s. Indeed, the A50s unit I had did not blow up any of my headphones. I also agree that Topping’s customer service has been less than stellar for those who did lose headphones and their ‘fix’ to the L30 isn’t entirely convincing. So I write this review as objectively as I can, with full acknowledgement that Topping should have done better and still has some PR cleanup to do, so that you as a prospective buyer go into potentially buying an A50s with full informed consent.

FEATURES & BUILD

The A50s is a balanced headphone amplifier built around the same circuit technology found in Topping’s flagship A90 amp. The A50s currently lists for $219.99, putting it very close to Schiit’s Magnius and Asgard 3 amps at $199 each (more on these later). The physical size of the A50s is rather shocking, actually, and not because it’s big. It’s precisely the opposite:

(that’s the matching D50s DAC on the left and top)

The outer chassis is all metal and quite rugged. You could probably drive over this thing with your car (disclaimer: don’t drive over an A50s or any amp or dac!) and it would be fine. You can see I got the silver finish version and it looks quite handsome, IMO. The back panel boasts the DC power input, and 2 pairs of RCA stereo analog connections for signal input and preamp output. Let me comment on further on the power supply, the input connections, and the preamp in the next paragraphs, because I think there are important points for each.

The included power cord is not great. It’s clearly intended as an internationally universal power cord because the plug portion is interchangeable. It’s also a bare-bones, fairly low-quality power supply that doesn’t match the build quality of the amp itself:

Flimsy power supplies are not new on amps in this price range and lower. Indeed, even the Monolith Liquid Platinum’s power supply, on an originally $799 unit, is on the chintzy side. The plug adapter that goes on the power cord here feels cheaper than most, though, and seems to me to be an easy fail point, not to mention a high risk of getting lost during a move or if you just drop the power cord accidentally and the adapter piece rolls under the fridge – who among us hasn’t lost something under the fridge?

The unbalanced RCA analog input initially puzzled me. At first it seemed like providing only unbalanced connections completely defeats the purpose of having a balanced amp, at least insofar as eliminating things like ground loop noise. And at this price point, eliminating ground loop noise is about the only advantage to having a balanced amp or DAC. However, credit where credit is due, the A50s still eliminates ground loop noise. My desktop computer has a rather annoying ground loop with USB DACs using unbalanced connections. I intentionally confirmed that a DAC was sending the ground loop noise out of is unbalanced output and ran it into the A50s. The A50s took it out. So, it does appear the A50s is in fact a fully balanced amp, with the lone true benefit of being balanced at this price, that uses single ended connectors for its inputs.

The preamp output and the headphone output switch automatically when a headphone is plugged in/out. I have grown to appreciate the feature of switching the headphone amp and preamp outputs – whether by a user-controlled toggle switch or an automatic switch – after using the Cayin HA-1AMK2 [link] tube amp that drove both the headphone amp and preamp at the same time, which could cause distortion. That’s not a worry here. However, the volume knob on the A50s is small, both in diameter and in how far it protrudes from the front faceplate and has a fair amount of resistance on it. I found it cumbersome to change the volume at times, and my fingers are smaller than average.

Back to the overall build quality…the front of the A50s sports the potentiometer knob, a 4.4mm pentacon balanced headphone output, and a 6.3mm (1/4 inch) unbalanced headphone output. There is also a button for power and gain level toggle. To turn the unit on and off, push and hold this button for about 2 seconds. To toggle between low gain (0 dB) and high gain (+6 dB), quick press this button. There are 2 white LEDs to indicate which gain level is selected. When the unit is powered on, one of these two LEDs will be lit. One more comment on the potentiometer, there is a low-level channel imbalance between about 6:30 and 8:00. This is another common problem for amplifiers with cheap pots, but for this price I think Topping could have used a higher quality pot.

Let’s talk about feet! There are 4 square rubber feet on the bottom of the A50s and they are some kind of sticky! The A50s isn’t heavy, but it’s also not light for its size. However, it’s light enough and small enough that a signal wire that hangs off a desk could slide it around but for these feet. Wow these things have some grip! I set up the A50s, its matching DAC (D50s), and a Schiit stack on a TV tray I commandeered to use as an end table next to the couch in my basement:

When I sat down the A50s was just outside of comfortable arm’s length to adjust the volume. So, I leaned over and grabbed the little Topping stack to slide it across the tabletop toward me. Nope! The whole darn table tipped over because those little feet are so darn sticky! These sticky feet were a smart addition, IMO. Because even bigger heavier amps like the Asgard 3 will slide around on a desktop when you try to push a headphone plug into it. I did not have that issue with the A50s.

Finally, power output. The A50s, from its balanced output, should have plenty of power for the vast majority of price-appropriate headphones. It’s rated at 3400mW per channel at 32Ω. And of course, it comes with all of the vanishing distortion numbers and sky-high SNR measurements for which Topping has earned a reputation and a following.

SOUND

The first thing I noticed about the A50s’ sound is what I didn’t hear. It has that utterly black sonic background that has become the expectation for the plethora of measurement-focused amps currently on the market. Once it starts amplifying an audio signal its sound is clean and smooth. These are the strengths of its sound: a virtually absent sonic background, and a clean, smooth sound.

Unfortunately, the A50s suffers from some of the same sonic issues that its cheaper sibling, L30, also suffered. The sound is too smooth – it’s oversmoothed to the point of sounding sluggish with poor separation between sounds for the price. The magnitude of that perceived sluggishness is not as much as the L30, but it’s present. That sluggishness also flattens the soundstage, dulls the imaging, and decreases detail retrieval. I have been listening to a lot of amps lately, including numerous amps under $200 [link to roundup here], and I’ve heard much better detail retrieval, spatial recreation, and general sense of life-like-ness than the A50s was giving me. The A50s also rolls off the bass below about 50 Hz, much like the L30 does. The magnitude of this roll-off is not as large the L30’s, but there is not as much deep-bass extension, punch, slam, quickness, or even bass quantity with A50s as with a number of even cheaper amps.

HEADPHONE PAIRINGS

The A50s appears to be most comfortable driving planar magnetic headphones. I got the best results with my Audeze LCD-2 prefazor. Some of that might be due to the fact that the LCD-2 has a magical ability to be relaxed and forgiving while also being detailed. My HiFiMan Edition X V2 sounded ok, but it’s a livelier headphone than the LCD-2 and that gap in liveliness wasn’t showing up much with the A50s. Ditto the last with the Massdrop + Sennheiser HD6XX. Especially at the price point the 6XX needs an amp with a little bit of sparkle and it’s not here. Strangely, the lack of sparkle and life on the 6XX made me think the Beyerdynamic DT880 600Ω - with that treble that some call “Mt. Beyer” - would be a good match, but alas, no. The DT880 was shrill and sharp on this amp – and that was using the balanced headphone amp on the A50s (my DT880 is balanced modded). When I first tried the A50s + DT880 pairing it was with the D50s DAC in the signal chain. I thought maybe most of that sharpness was due to the ESS chip implementation of the D50s. Switching to the Schiit Modius DAC helped, but did not come close to eliminating that sharp treble. Going all-Schiit with Modius and either Magnius or Asgard as amps brought that treble under much more control. The DT880 is also the spatial-performance reference point for <$200 headphones, IMO, and with the A50s the staging was flatter and the imaging more blended together than other budget amps can pull off.

COMPARISON WITH OTHER AMPS

When I listened to just the A50s for awhile, over time, my brain adjusted and I became less distracted by its deficiencies. I even tapped my toes and bobbed my head a few times. But as soon as I would switch back to another amp – even slightly cheaper ones like the Magnius and Asgard 3 – it’s like the world of music opened up again. The A50s, unfortunately, is simply behind its competition on detail retrieval, spatial re-creation, timbre, dynamics, and I think this picture is clear enough without belaboring the point further. It is true the A50s wins the measurement race at its price point, but that does not translate to sonic performance. Magnius is just behind it in the measurement game, and Asgard – while it’s not a measurement chaser – measures well beyond any threshold of concern. I can only recommend the A50s if 1) the buyer lives in a location where obtaining products made by Schiit, JDS Labs, Monolith, Geshelli Labs, or iFi is difficult/pricey; 2) desk space is top priority; and 3) there’s a ground loop issue in the system. And even if those things are true, the L30 amp and a $10 RCA ground-loop isolator is likely the better value, provided enough time passes that buying the L30 feels safe again.

FINAL THOUGHTS

May I level with you readers and say that this review was really difficult for me? My honest opinion on this product is at odds with many reviewers who are far more established than I. That’s an awkward position to be in as someone hoping to launch a reviewing ‘side hustle’ – for lack of better term, haha. Some may say that I’m simply not used to the ultra-clean sound that a measurement-champ-amp and I dislike it because I’m unfamiliar with it. It’s true that when given a choice I gravitate toward sound signatures more often associated with Class A, Class A/B, or tube amps (and let’s also be clear that there is lots of variation in sound signature within those amp types, too). But, it’s also unfair to say I’m unfamiliar with squeaky-clean, measurement chasing sound; I’ve owned the JDS Labs Atom and the SMSL SP200 and put hundreds of hours on both. I’ve also reviewed the Topping L30, Geshelli Labs Archel 2 GMR, and the Schiit Magnius – all amps that seek to minimize distortion measurements and drive up SNR and SINAD measurements. The available evidence shows Topping’s approach has been to maximize results on a certain subset of quantities that can be measured in an audio signal. For some product categories that translates to good-sounding results when music is playing. I have favorable opinions of their D10 and E30 DACs, for example. For amps though, the approach seems to be a bit too all-in on the measurement side. IMO, JDS Labs, Geshelli Labs, and Schiit have shown that chasing measurements doesn’t mean that sound quality during music playback also has to be sacrificed to the degree that my ears tell me with Topping amps. I don’t have all the answers as to why measurement excellence doesn’t always add up to excellent sound quality. However, it appears to me that there is a framing within the audiophile community that focuses more on what an amp (or DAC) does not do more than what an amp (or DAC) does do. To me, focusing on vanishing distortion and making sure SNR or SINAD measurements reach Everest-like heights is focusing on what an amp should not do – mess up the audio signal with excess noise or alter a waveform from what comes in. What gets lost when that becomes such a dominant focus seems to be what an amp should do – increase the amplitude of the audio waveform while making sure voices sound like voices, pianos sound like pianos, etc. and place those sounds in a sonic space that sounds convincing and real. Unfortunately, we don’t have a good way to measure timbre or soundstage and imaging beyond what we hear with our own ears. Some will still reply that our senses are imperfect and our ears and sonic memories cannot be trusted, therefore we need objective standards. I completely agree that our senses and memories are subject to all sorts of biases and flaws. I also respectfully disagree that that means they should be discounted. The science that the objective measurements being used in audio is based on owes its very existence to the careful application of human senses in observing natural phenomena. Our eyes and ears (and nerve endings and taste buds when appropriate – do not lick a circuit board!) and qualitative descriptions of what they tell us are central to our understanding of pretty much everything; we can’t just discount them.

The Topping A50s amp has a sturdily-built chassis and a thoughtful touch on the inclusion of sticky rubber feet that make it slide around a desktop very little. It also has a form factor that some will find attractive. It has plenty of power, a virtually absent sonic background, prodigious distortion and noise measurements, and a generally clean, smooth sound. However, at $220 it does not compete with its closest competition in overall sound quality and I cannot recommend it.

Thanks for reading, all, and as always, enjoy the music! :beers:

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Great review as always, its a shame that the topping stuff isn’t as good as the competition, the form factor and availability would make it so good if they could stand up to an A3/Magnius.

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Thanks, Kron!

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I’ve read through the specs of the A50s. It presented as an amp that puts out 3,5W @32 Ohm. So as a warning for those considering this because of the power:

  1. Thats only into balanced. SE peaks at 1,4 [email protected] (No surprise here)
  2. The power is only reached when the amp is connected to very strong DAC. At 2 Vrms (what most dacs in the price category AND also the matching D50s have) the amp will only have 1,95W @32 Ohm BE and 0,485W @32 Ohm SE.
    So when connected to a “normal” DAC it looses like half of the claimed power.

Correct me if I am wrong but this sound almost like a joke. Or is this a common thing with all amps?
I just wanted to put this out so people are not fooled by the advertismend because these infos are only found, when one diggs deeper into the specs.

In controlled settings, it is very possible to produce any number you want.

Single Ended being half the power of balanced is an artifact of lazy design, honestly.

Usually that’s common in fully balanced amp with balanced input 'cause the balanced line is stronger.

If the balance amp is symmetrical or it doesn’t attenuate the signal or change the gain when used in balanced actually the balanced out is 4 times more powerful than the se theoretically.

That sentence does not make any sense.

Let me reword that:

If the balanced amp is balanced, or changes gain


Cheaping out and tapping the single ended output on an amplifier off half the balanced is a common hack job. And in those cases, as voltage is halved, it results in half the power.
Power wise, correctly implemented single ended can deliver the same power as balanced. The path to get there is what is different.

One look at the Asgard 3 beeing proof.

it does

attenuation of a signal or reduction of the internal amplifier gain are different things

What is “correct” may vary

Hey guys

Any idea why screw on 6.35mm jack adapter would cause trouble with this headphone amp? There is cracking in sound and no bass and when i turn the volume up, amp just turn off, its like its sorting something and it has protection so it turns off. But why would it short something? When i use 6.35mm adapter that came with this amp, there is no problem.

I have Beyerdynamic headphones and that adapter that screws on was part of accessories.

It sounds like the screw on adapter is defective/broken. Also make sure there isn’t any debris in the adapter.

i tried compressed air now but its the same, i throw this away and just use that adapter that came with the amp, i dont want to destroy amp or headphones, maybe i buy new but i think screwable adapter is not necessary

strange thing that it worked until now, i thought that amp is dying but i tried different adapter and it is working

i have one more question, is there a way to increase / amplify 2 Vrms input without a DAC?
in some scenarios i can max the volume and i mean its loud but i could go louder, i have Beyer headphones with 250 ohm impedance and its power handling capacity is 100mW and im getting maybe 60mW or something with 2 Vrms input cuz output power is 52 mW [email protected]Ω with 2 Vrms

i didnt know what that 2 Vrms mean, only now i found out so im thinking about going back to A50 which has 160 mW [email protected]Ω with 2 Vrms (i gave it to my friend, so maybe i give/sell him A50s)

to me its strange that amp power is depended on audio signal voltage, even more so when 2 Vrms seems to be a standard… i thought that, when it has its own power from the wall to amplify then signal voltage plays no role in this

EDIT: or just tell me how to get this output from it - Jack 6.35mm: 2x 192mW @ 300Ω if its even possible

You could potentially use a preamp to increase signal strength, but increasing voltage/pre-gain can have a tendency to also raise the noise floor depending on how it’s done. Just something to be aware of. If you’re driving high impedance cans like the HD650/6XX at 300 ohms, that’s less likely to cause problems than something that’s more sensitive.

so what would you recommend? what device? i mean specific model, just it should not be very expensive cuz then it does not make sense
or is there an adapter 3.5mm jack to 4.4 balanced and it would work? so i would connect unbalanced headphones into balanced out

and yeah as i said, i have Beyerdynamic headphones with 250 ohm impedance

Apart from power concerns, are there other things you’d want to change about the amp?

Honestly, if the A50s isn’t giving you enough on the Beyers, it might be worth considering selling the A50s for something that is designed to run single ended headphones, which is more of an afterthought on most amps that offer a balanced output. In the $100 range, something like Liquid Spark, JDS Atom, or Magni 3+/Heresy. A couple of those can also act as a preamp. The Heresy and Atom would be more analytical leaning, while the Magni and Spark lean a bit warmer.