Topping L70 Headphone Amp Review

[Veri]

@vintagelove Afaik, Topping spec input sensitivity only as a function of max output voltage and gain, e.g:
View attachment 248186
sqrt(600mW*600Ω)*10^(-19.8dB/20)≈1.9Vrms

So the max input voltage before the Amp clips at full gain.

It's possible that if you reduce the Amp's volume by, say, 30dB, you can input more voltage than what the specs say.
We don't know at what point the L70's input will clip. Only the output.

Always a source of good knowledge @staticV3

 

[vintagelove]

@vintagelove Afaik, Topping spec input sensitivity only as a function of max output voltage and gain, e.g:
View attachment 248186
sqrt(600mW*600Ω)*10^(-19.8dB/20)≈1.9Vrms

So the max input voltage before the Amp clips at full volume.

It's possible that if you reduce the Amp's volume by, say, 30dB, you can input more voltage than what the specs say.
Basically, we don't know at what point the L70's input will clip. Only the output.

I appreciate the response. Coming from the studio world, it just seems like such an odd measurement/spec to leave out.

Well, if anyone that has it could measure when the front end clips it would be much appreciated. Thanks again.

 

[solderdude]

Depending on the design (relay volume control directly before the amplifier) it may well not have a max. input voltage.
Only @JohnYang1997 can answer this one.
When the input is buffered it may well clip above 9.5V or so (+22dBu, +19.3dBV) assuming the power supply voltage of the buffer opamps is +/-15V.
There may well be a balanced -> unbalanced circuit directly on the input.

 

[Kevinfc]

Ho hum, another superb Topping review. No sarcasm intended, but I hardly need to read them any more. Good job guys.

 

[DRuszaT]

Agreed, and that's a valid reason to keep testing these. Now we can decide if we want the performance of the A90D for €700 or something almost as good for €400.

I bought both and paid a total of USD 858 for them. The A90D is a sleek dancer, while the L70 is a weightlifter, both do their job with ease. It's likely that Topping's next leap forward will be to combine the beauty of the A90D with the display features of the L70 in another perfect work of art...

 

[Badunn]

First, there's no such thing as "balanced" headphones. It's just differential.

Single Ended, Balanced & Differential - What it Means

One of the most common points of confusion, and questions raised, relates to the differences between, and meanings of, the terms “single ended”, “balanced” and “differential” operation. And, further to that, what the qualifier “fully” (as in “fully balanced”) means in relation to these terms...

forum.headphones.com

But because they often use the some jacks people conflate the two.

Second, no.

First, there's no such thing as "balanced" headphones. It's just differential.

Single Ended, Balanced & Differential - What it Means

One of the most common points of confusion, and questions raised, relates to the differences between, and meanings of, the terms “single ended”, “balanced” and “differential” operation. And, further to that, what the qualifier “fully” (as in “fully balanced”) means in relation to these terms...

forum.headphones.com

But because they often use the some jacks people conflate the two.

Second, no.

I’m only using the term stated. Manufacturers should be clearer if either one or the other.

 

[Badunn]

Answer is already given but here is a video I created to answer questions around balanced connections:

Great video! Totally get it now. Felt like you were talking to me directly as well …is that weird?!

 

[Robbo99999]

@amirm , in your conlusion you say "Even though the HD650 is deficient in bass you would not know it while driving it with L70" - isn't it a bit dangerous to say that, this is almost like those strange kind of "synergy" arguments that the subjective audio crowd often use. What I mean is that the amplifier is not changing the frequency response of the headphone, why would the amplifier change the perceived bass level of the headphone?

Nice review & nice headphone amp though!

 

[solderdude]

The louder one plays the more the bass levels become elevated, relatively that is due to equal loudness contours.
One could say at louder levels the lower bass 'snaps in place'.
In order to do so you need a lot of power.... well voltage actually, the HD650 is very efficient just not very sensitive.
As the L70 can supply a high voltage (like many other amps) and does so cleanly you can make the HD600/6XX/650 have plenty of low bass but.... it will be loud.

 

[kemmler3D]

So the A90 is currently selling for around $350 on eBay secondhand. This is $350 now. In a few years, what do you think will hold its value better? This one has a remote, after all...

 

[renaudrenaud]

So the A90 is currently selling for around $350 on eBay secondhand. This is $350 now. In a few years, what do you think will hold its value better? This one has a remote, after all...

Has a remote and a readable screen.

 

[kemmler3D]

Has a remote and a readable screen.

Yes, but as resale value is typically a fraction of retail, the real question is how fast do we think the A90 is depreciating? When will it hit $175 or so on eBay, your best guess?

 

[gmoney]

I think the defining feature of this is its select-able output. I hate having to switch headphones constantly between open/closed and this eliminates that process by letting you keep up to 3 plugged in with their own volume levels saved. I know the not another topping amp/dac thing keeps getting regurgitated but AFAIK this is a legitimate new and useful feature.

 

[renaudrenaud]

Yes, but as resale value is typically a fraction of retail, the real question is how fast do we think the A90 is depreciating? When will it hit $175 or so on eBay, your best guess?

Well resale value is not in completely in my equation. I bought plenty of gears and distribute them to the family.

I buy audio gear since 40 years. Now we have something with stellar performance and the cost is near nothing in comparison to the prices we used to pay. From my point of view, I just decided to enjoy!

 

[Urib]

This is a review and detailed measurements of Topping L70 balanced headphone amplifier. It was sent to me by the company and costs US $349.
View attachment 247901
The L70 has the beautiful white segmented display. It is the most visible/high contrast display I have seen on an audio product. Volume control is very responsive and is relay based to provide perfect channel matching. You get both unbalanced and balanced output with the latter providing substantially more power. A remote control is provided. Back panel shows some nice extra features:
View attachment 247902
You have 12 volt trigger to power it on or have its power switch power other gear. A ground lift is provided as well to help with ground loops. And my favorite feature which is an included power supply.

A microprocessor controls the conditions of the unit and shuts it off or limits output as needed. Different error messages in the form of "r-" are provided when this happens. I pushed the unit routinely and repeatedly into clipping and overload with no ill effect. But please note that both headphone and power amps are subject to failures due to varying load/usage so if you are risk averse, you may want to wait for others to test it before deciding on purchasing it.

Topping L70 Balanced Measurements
I hooked up the L70 using its XLR input and measured its XLR balanced headphone output. In the next section you will see unbalanced performance. Let's start with our dashboard:
View attachment 247903
I was amazed to see distortion at incredibly low -145 dB! This is some 30 dB better than our best case hearing threshold! SINAD which sums noise and distortion is noise limited to the tune of 120.4 which lands the L70 near the top of our rankings:
View attachment 247904
Speaking of noise, that is also excellent:
View attachment 247905
50 millivolt rating is excellent and the only thing keeping it from topping the charts completely is the fact that there is no negative gain setting:
View attachment 247906

Still, 93 dB is superb meaning that you almost get the dynamic range of the CD even though you are listening at just 0.05 volts!

Frequency response is as flat as we need:
View attachment 247907

The low distortion shows off again in multitone test:
View attachment 247908

After noise, power is everything in a headphone amp so let's see how the L70 does with its XLR output:
View attachment 247909
I like to see > 100 milliwatts and the L70 accomplishes that in Low Gain!!! In high gain, it blows the doors open with 1 watt of power. This should let it drive high impedance with ease.

The dynamics get even better with 32 ohm:
View attachment 247910

We get a stunning 7 watts in high gain now! Even in low gain we have nearly 2 watts. And it does this while keeping its composure and not even clipping.

Changing the load we get the same superb results:
View attachment 247911

Topping L70 Unbalanced Measurements
Changing the output to 1/4 inch gets us the same superb dashboard:
View attachment 247913

Power is naturally low but still very healthy:
View attachment 247914
View attachment 247915

Topping L70 Listening Tests
I started testing with my Dan Clark Expanse headphone using XLR connection. This is a low impedance and insensitive headphone which breaks the back of many headphone amplifiers. Not here. The L70 dominated it like nobody's business. In high gain, I did not dare to get anywhere near the max volume. There was so much power that it drove the right channel of the headphone into crackling with bass notes. Mind you, this was *at extremely* high volume level. Way past threshold of comfort. Yet, the L70 had more power left on the volume control! The sound and overall experience was exceptional with super detail and dynamics.

I then switched to Sennheiser HD650 which is easier to drive. The sound was yet again superb with some 30 dB of headroom left on L70. If I didn't have to finish the review by taking a picture of the L70, I would still be sitting there listening to this combo! Even though the HD650 is deficient in bass you would not know it while driving it with L70. The sound was superbly clean and enjoyable.

Conclusions
As much as Topping has made us expect superb engineering, I am still surprised when I unbox and measure/experience their newer offerings. The L70 innovates with wonderful new front panel and incredible power and low noise and distortion. It has level of performance that enables you to buy and enjoy any headphone regardless of insensitive or difficult it is to drive. Nice features like R2R relay control solves the problem of analog volume controls causing channel mismatch, giving you a perfect experience even with sensitive IEMs/headphones. I like to find something to complain about I just can't!

It is my pleasure to recommend Topping L70 headphone amplifier.

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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/

I still wait for their power amps to match the A90 preamp. Why the he'll they wait with this so much?

 

[solderdude]

I still wait for their power amps to match the A90 preamp. Why the he'll they wait with this so much?

LA90

 

[Robbo99999]

The louder one plays the more the bass levels become elevated, relatively that is due to equal loudness contours.
One could say at louder levels the lower bass 'snaps in place'.
In order to do so you need a lot of power.... well voltage actually, the HD650 is very efficient just not very sensitive.
As the L70 can supply a high voltage (like many other amps) and does so cleanly you can make the HD600/6XX/650 have plenty of low bass but.... it will be loud.

Yes, I had considered that, but then I thought you'd still be able to detect it was somewhat insufficient in bass, and certainly different to say a Stealth played at any volume, so it seemed a surprising statement to me. I also think most headphone amps reviewed on this site would be able to get the HD650 to loud enough levels that the whole Fletcher Munson Curve thing is overcome.

There's not much difference between 90dB and the louder levels, and you could probably make the same case for the 80dB curve or at least the curves between 80dB and 90dB that aren't pictured. Pretty much all headphone amps can drive an HD650 to 90dB I would think.

 

[theREALdotnet]

I gave it one for the OLED display alone,otherwise I would have given it fine (to give great must be proved reliable over time too)
(I'm in an open war with OLED displays,I like to be able to read a screen more than 1 or 2 years after i get it)

I prefer Nixie tubes, they have greater depth.

 

[Anthony T]

Would it really have been so much trouble to line the headphone sockets up horizontally?

 

[Sokel]

I prefer Nixie tubes, they have greater depth.

Why not neon signs?