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Topping L30 Headphone Amplifier Review

JohnYang1997

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What does this mean? if another amp does not have distortion, this is why Im worried.
Different output jack, different plug, different cabling. 4pin XLR vs 6.35mm TRS. It's basically a different test setup. Of course there will be different effects.
 

Veri

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What does this mean? if another amp does not have distortion, this is why Im worried.
He's talking about the way the measurement machine is wired. Over on the SBAF side. Pic above shows how JohnYang wired it. This is why you can't compare measurements in an apples to apples kind of way..
 

solderdude

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Again.... there IS no higher distortion. It is an 'illusion' of higher distortion caused by resistance of the amp output + ground and back EMF from the headphone. It does NOT represent the amps performance. They just believe it is a HUGE issue. It's a huge misinterpretation of measurements though.

For balanced there are only 2 amps, the ground is not connected so can have no part.
The balanced amp used has higher distortion by itself than the L30 so while the Schiit appears to have lower distortion in reality it doesn't and even has a poorer harmonics spread. The output resistance of the Schiit will also be somewhat lower.

Forget that thread they are what Marv would call 'borked measurements' but in this case most likely due to ignorance and intended to serve as proof that Topping and ASR are 'bad' and don't understand measurements where ironically he is the one not understanding what he measures but thought it might make good material for 'propaganda'.
 
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filipduarte

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Forget that thread they are what Marv would call 'borked measurements' but in this ase most likely due to ignorance and intended to serve as proof that Topping and ASR are 'bad' and don't understand measurements where ironically he is the one not understanding what he measures but thought it might make good material for 'propaganda'.

I stand for what you are saying.
I went through that rabbit hole and man... :facepalm:
I only see hatred, childish claims, and conspiracy theories.
They are angry that their expensive US/European-made equipment is showing bad results and missing the point.
If they like how their equipment sounds, fine, just stick with you like, that's all.
I prefer to have a clear amplifier and adjust to my preferences through EQ.
If you prefer to play with synergy and experiment with equipment to find the perfect fit, it's ok too.
 

shoto

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Again.... there IS no higher distortion. It is an 'illusion' of higher distortion caused by resistance of the amp output + ground and back EMF from the headphone. It does NOT represent the amps performance.

For balanced there are only 2 amps, the ground is not connected.
The balanced amp has higher distortion than the L30 so while the Schiit appears to have lower distortion in reality it doesn't and even has a poorer harmonics spread. The output resistance of the Schiit will also be somewhat lower.

Forget that thread they are what Marv would call 'borked measurements' but in this case most likely due to ignorance and intended to serve as proof that Topping and ASR are 'bad' and don't understand measurements where ironically he is the one not understanding what he measures but thought it might make good material for 'propaganda'.
Ok it is not the L30, but does it mean there will be less distortion somewhere if you use a balanced amplifier or the distortion only shows in measurements instead of listening?
 

solderdude

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Distortion profile of balanced is different. 2nd harm will be less (headphones have higher 2nd harm) and 3rd harm will be slightly higher because 2x 2nd harmonic 'cancel' and effectively become symmetric (3rd).

The only advantage of a balanced output is the common wire in SE is no longer common and it is easier to create a higher output voltage from a given DC power supply voltage (think low voltage gear such as portable equipment)
 

JohnYang1997

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Ok it is not the L30, but does it mean there will be less distortion somewhere if you use a balanced amplifier or the distortion only shows in measurements instead of listening?
The distortion does not belong to the amplifier. The amplifier itself didn't generate it.

In practical real world listening. The headphones have much higher distortion than the amplifier.
Eventually, what it means is that the amplifier is designed so well that you can be certain the amplifier doesn't add anything. For power hungry cans and extremely sensitive iems it could still be an issue, but not here. Only one thing potentially is you may not get enough loudness due to the gain is only +9.5dB.
 
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amirm

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Hi

I would also like to ask about the SBAF thread for Topping L30.
We went through this three years ago. Benchmark had published a paper saying this is an issue. Turns out it is not for all the reasons that are mentioned.

See: https://www.audiosciencereview.com/...ments-of-rme-adi-2-dac.2582/page-5#post-74064

index.php


And some follow ups by excluding noise: https://www.audiosciencereview.com/...measurements-of-rme-adi-2-dac.2582/post-75128

index.php


So their observations are nothing new.

At the end, it became clear that we were measuring the headphone, not the amp. Just making noise by the headphone impacts this test as the headphone acts like a microphone. As noted by John and Solderdude, how you tap the output makes a big difference as well due to impedances involved.

Nothing about this test is "real world" anyway as one doesn't listen to the input of a headphone but the output! Measuring the input there just gives you false results as they are experiencing.
 

shoto

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We went through this three years ago. Benchmark had published a paper saying this is an issue. Turns out it is not for all the reasons that are mentioned.

See: https://www.audiosciencereview.com/...ments-of-rme-adi-2-dac.2582/page-5#post-74064

index.php


And some follow ups by excluding noise: https://www.audiosciencereview.com/...measurements-of-rme-adi-2-dac.2582/post-75128

index.php


So their observations are nothing new.

At the end, it became clear that we were measuring the headphone, not the amp. Just making noise by the headphone impacts this test as the headphone acts like a microphone. As noted by John and Solderdude, how you tap the output makes a big difference as well due to impedances involved.

Nothing about this test is "real world" anyway as one doesn't listen to the input of a headphone but the output! Measuring the input there just gives you false results as they are experiencing.
It seems from your test that some amplifiers, in that case Benchmark amplifier, do not have this distortion.
If this distortion is from the headphone how can the Benchmark amp not have it when tested in the same way?
 
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amirm

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It seems from your test that some amplifiers, in that case Benchmark amplifier, do not have this distortion.
That was the kicker: later on I got the benchmark amp and it too had the same distortion in the same test setup!
 

shoto

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What is the name of benchmark amp or can you link the follow up test? thanks
 
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amirm

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What is the name of benchmark amp or can you link the follow up test? thanks
Here you go: https://www.audiosciencereview.com/...ents-of-benchmark-dac3.3545/page-2#post-85580

Dummy load:

index.php


With Sony headphone as the load:

index.php


I should note that multiple designers objected to this type of testing including Andrew Mason of THX and Mathias of RME. They were right. :)

To be clear, if you build a low impedance kelvin type fixture to sample the output and then the problem would not exist. And then if you compare the same setup with a high impedance headphone amp, it would. This is what the original Benchmark paper showed. We (and SBAF) ran foul of building the wrong version of this fixture and thinking that two low very low impedance headphone amps would have the same problem. They do not. This is why I stopped using this setup back in 2018.
 

solderdude

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Again... what is 'measured' is not distortion that supposedly is increased by the amplifier.
It is attenuated back EMF that is added to the test signal.

The proof for that is really easy. Just flip on the measurement device but do not start the test and put the headphone against a speaker making the sweep. You will see the 'distortion'.

It really isn't that hard to figure out the 'distortion' isn't coming from or caused by the amp. It is voltage division of back EMF.
The lower the output R the lower the 'added signals' are.

The reason Marv cannot replicate what JohnYang measured is the test setup (as JohnY already mentioned).
JohnY was smart enough to use the splitter directly at the L30 (and even that adds small resistance). Marv uses a cable that adds output resistance basically and splits after a cable and thus Z2 (in my previous post) is higher so the 'effect' is bigger.

If only he used a speaker amp (a real one with really low output R) and repeated the same measurement but splitted directly at the speaker terminals and then repeat the measurements with small resistors (of different values) between the speaker terminal and the splitting point it would be really easy to verify the cause.

This is basic ohms law stuff with 2 signal generators both 'injecting' their own signals which combine and is what is measured. There is no mystery here. One just has to experiment a bit and stop looking through certain glasses.
 
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amirm

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John was smart enough to use the splitter directly at the L30 (and even that adds small resistance). Marv uses a cable that adds output resistance basically and thus Z2 (in my previous post) is bigger so the 'effect' is bigger.
That was the issue in my original dummy load/test fixture as well.
 

shoto

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Here you go: https://www.audiosciencereview.com/...ents-of-benchmark-dac3.3545/page-2#post-85580

Dummy load:

index.php


With Sony headphone as the load:

index.php


I should note that multiple designers objected to this type of testing including Andrew Mason of THX and Mathias of RME. They were right. :)

To be clear, if you build a low impedance kelvin type fixture to sample the output and then the problem would not exist. And then if you compare the same setup with a high impedance headphone amp, it would. This is what the original Benchmark paper showed. We (and SBAF) ran foul of building the wrong version of this fixture and thinking that two low very low impedance headphone amps would have the same problem. They do not. This is why I stopped using this setup back in 2018.
You say in this test it is Benchmark DAC3 when Benchmark's measurement graphs were for DAC1. Can you give more details about similar claims for DAC3? Did it also have the new measurements graphs showing the effect for DAC3?
If not I don't think that it is fair comparison, but if they have same graphs for DAC3 it will show they are dishonest about the measurements.
 

dmac6419

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Basically, the test setup and the person who performs the test are not good enough for precision analogue measurements.
Marvey trying to make a name for himself,owner on his slong and vice versa,they wanna be big boys,but I have to wonder why they can't hang on their own laurels
 

confucius_zero

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With planar the big difference was in bass, less impactful/loose with quicker roll-off, better amping brought tight/well extended bass.
I felt the same with my L30 I bought within months of interval to make sure I got another batch... that bass rolloff is felt everytime. I wonder if there's an objective measurement that can highlight this glaring deficiency or are the headphones to blame.
 
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